• Title, Summary, Keyword: {\Phi}-Divergence$

Search Result 10, Processing Time 0.04 seconds

SOME INEQUALITIES FOR THE $CSISZ{\acute{A}}R\;{\Phi}-DIVERGENCE$

  • Dragomir, S.S.
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.7 no.1
    • /
    • pp.63-77
    • /
    • 2003
  • Some inequalities for the $Csisz{\acute{a}}r\;{\Phi}-divergence$ and applications for the Kullback-Leibler, $R{\acute{e}}nyi$, Hellinger and Bhattacharyya distances in Information Theory are given.

  • PDF

Local Sensitivity Analysis using Divergence Measures under Weighted Distribution

  • Chung, Younshik;Dey, Dipak K.
    • Journal of the Korean Statistical Society
    • /
    • v.30 no.3
    • /
    • pp.467-480
    • /
    • 2001
  • This paper considers the use of local $\phi$-divergence measures between posterior distributions under classes of perturbations in order to investigate the inherent robustness of certain classes. The smaller value of the limiting local $\phi$-divergence implies more robustness for the prior or the likelihood. We consider the cases when the likelihood comes form the class of weighted distribution. Two kinds of perturbations are considered for the local sensitivity analysis. In addition, some numerical examples are considered which provide measures of robustness.

  • PDF

ON THE GOODNESS OF FIT TEST FOR DISCRETELY OBSERVED SAMPLE FROM DIFFUSION PROCESSES: DIVERGENCE MEASURE APPROACH

  • Lee, Sang-Yeol
    • Journal of the Korean Mathematical Society
    • /
    • v.47 no.6
    • /
    • pp.1137-1146
    • /
    • 2010
  • In this paper, we study the divergence based goodness of fit test for partially observed sample from diffusion processes. In order to derive the limiting distribution of the test, we study the asymptotic behavior of the residual empirical process based on the observed sample. It is shown that the residual empirical process converges weakly to a Brownian bridge and the associated phi-divergence test has a chi-square limiting null distribution.

Numerical Study on the Effect of Non-Equilibrium Condensation on Drag Divergence Mach Number in a Transonic Moist Air Flow (천음속 익형 유동에서 비평형 응축이 Drag Divergence Mach Number에 미치는 영향에 관한 수치 해석적 연구)

  • Choi, Seung Min;Kang, Hui Bo;Kwon, Young Doo;Kwon, Soon Bum
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.40 no.12
    • /
    • pp.785-792
    • /
    • 2016
  • In the present study, the effects of non-equilibrium condensation on the drag divergence Mach number with the angle of attack in a transonic 2D moist air flow of NACA0012 are investigated using the TVD finite difference scheme. For the same ${\alpha}$, the maximum upstream Mach number of the shock wave, Mmax, and the size of supersonic bubble decrease with the increase in ${\Phi}_0$. For the same $M_{\infty}$, ${\Phi}_0$, and $T_0$, the length of the non-equilibrium condensation zone ${\Delta}_z$ decreases with increasing ${\Phi}_0$. On the other hand, because of the attenuating effect of non-equilibrium condensation on wave drag, which is related to the interaction between the shock wave and the boundary layer, the drag coefficient $C_D$ decreases with an increase in ${\Phi}_0$ for the same $M_{\infty}$ and ${\alpha}$. For the same ${\alpha}$, $M_D$ increases with increasing ${\Phi}_0$, while $M_D$ decreases with an increase in ${\alpha}$.

Divergence-free algorithms for moment-thrust-curvature analysis of arbitrary sections

  • Chen, Liang;Liu, Si-Wei;Chan, Siu-Lai
    • Steel and Composite Structures
    • /
    • v.25 no.5
    • /
    • pp.557-569
    • /
    • 2017
  • Moment-thrust-curvatures ($M-P-{\Phi}$ curves) are fundamental quantities for detailed descriptions of basic properties such as stiffness and strength of a section under axial loads required for accurate computation of the deformations of reinforced concrete or composite columns. Currently, the finite-element-based methods adopting small fibers for analyzing a section are commonly used for generating the $M-P-{\Phi}$ curves and they require large amounts of computational time and effort. Further, the conventional numerical procedure using the force-control method might encounter divergence problems under high compression or tension. Therefore, this paper proposes a divergence-free approach, combining the use of the displacement-control and the Quasi-Newton scheme in the incremental-iterative procedure, for generating the $M-P-{\Phi}$ curves of arbitrary sections. An efficient method for computing the strength from concrete components is employed, where the stress integration is executed by layer-based algorithms. For easy modeling of residual stress, cross sections of structural steel components are meshed into fibers for strength resultants. The numerical procedure is elaborated in detail with flowcharts. Finally, extensive validating examples from previously published research are given for verifying the accuracy of the proposed method.

Experimental and Numerical Study on Performance Analysis of a Planar Diffuser (평판형 디퓨져의 성능해석에 관한 실험 및 수치해석)

  • 조대환;이철재;배석태;김성동
    • Proceedings of the Korean Society of Marine Engineers Conference
    • /
    • /
    • pp.63-68
    • /
    • 2001
  • In wide angle diffuser, the cross-sectional area increases so rapidly that separation can be avoided only by using boundary layer control. In this study, an experimental and numerical study is performed on performance of a diffuser with guide damper. A series of measurements were carried out to investigate the characteristics of diffuser for different divergence angle(${\phi}=7^{\circ}, \;10.5^{\circ}\;and\; 14^{\circ}$) of guide damper and angle of ${\phi}=10.5^{\circ}$ was through to be the best among three cases. Judging from the results, guide damper can be used as an effective means of improvement for diffuser performance.

  • PDF

A Transitional Behavior of a Premixed Flame and a Triple Flame in a Lifted Flame(II) (부상화염에서 예혼합화염과 삼지화염의 천이적 거동(II))

  • Jang Jun Young;Kim Tae Kwon
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.3
    • /
    • pp.376-383
    • /
    • 2005
  • In the paper we investigate characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. In previous study, we showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. A gas-chromatograph is used to measure concentration field, a smoke-wire system is used to measure streak line, and a PIV system is used to measure velocity field in lifted flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. In PIV measurement, flow velocity for those three flames has minimum value at the tip of flame front. To differentiate triple flame and premixed flame, $\Phi$ value of partially premixed fraction is employed. The partially premixed fraction $\Phi$ was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.

Behaviors of Premixed Flames and Triple Flames with its Concentration Difference in a Slot Burner (슬롯버너에서 농도차이에 따른 예혼합화염과 삼지화염의 거동)

  • Kim, Tae-Kwon;Jang, Jun-Young;Park, Jeong;Jun, Seong-Hwa;Miwa, Kei
    • 한국연소학회:학술대회논문집
    • /
    • /
    • pp.85-90
    • /
    • 2004
  • We have presented characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. The experimental apparatus consisted of a slot burner and a contraction nozzle for a lifted flame. As concentration difference of the both side of slot burner increases, the shape of flame changed from a premixed flame to a triple flame, and the liftoff height is decreased to the minimum value and then increase again. Around this minimum point, it is confirmed a transition regime from premixed flame to triple flame. Consequently, the experimental results of the liftoff height, flame curvature and luminescence intensity showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. To differentiate triple flame and premixed flame, ${\Phi}$ value of partially premixed fraction is employed. The partially premixed fraction ${\Phi}$ was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.

  • PDF

Numerical Study of Planar Diffuser Flows at Very Low Reynolds numbers (저 레이놀즈 수 평판 디퓨져 유동 수치적 연구)

  • Oh Jong-Yun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.110-113
    • /
    • 2005
  • This paper presents flow regime maps of two-dimensional, planar diffusers with constant-area ducts at very low Reynolds numbers. They are obtained from numerical calculations using the commercial CFD program CFD-ACE+. The Reynolds numbers considered are 63, 105, and 210. For each Reynolds number, a wide range of geometric parameters of dimensionless diffuser length, which is a ratio of diffuser length to throat width, $1 and divergence half angle $1^{\circ}<\phi<50^{\circ}$ are selected to obtain steady-state solutions. These maps can be served as a guideline to designers for very low Reynolds number diffuser flows.

  • PDF

Mitochondrial DNA Polymorphism of the Japanese Anchovy (Engraulis japonicus Temminck & Schlegel) Collected from the Korean Offshore and Inshore Waters (한국근해 및 외해역에 채집된 멸치의 미토콘드리아 DNA 다양성)

  • Cho, Eun-Seob;Kim, Joo-Il
    • Journal of Life Science
    • /
    • v.16 no.5
    • /
    • pp.812-827
    • /
    • 2006
  • To investigate the population structure and geographic distance among anchovies (Engraulis japonicus) in Korea, we compared and analyzed the mitochondrial DNA control region sequences (227 bp) of anchovies from 12 localities in inshore and offshore waters. The sequence analysis of 84 individuals showed 29 haplotypes, ranging in sequence divergence by pairwise comparisons from 0.3% to 3.5% (1 bp-12 bp). E9 haplotype of anchovies were found largely in inshore waters and also in offshore waters, which was regarded as the major source in Korean waters (58.3%). However, E26, E27, E28, and E29 haplotypes were found in westsouthern (locality 10, four among 7). Phylogenetic analysis using PHYLIP was divided into two clades (clade A and B). Most of the haplotypes, excluding E26, E27, E28, and E29, were strongly supported by bootstrap analysis (>75%), whereas the relationship between clade A and B was weakly supported by bootstrap analysis (51%). High levels of genetic diversity were found; haplotype diversity (H)=0.75-1.00, and nucleotide diversity $({\pi})=0.015-0.0244$. Analysis of $F_{ST}$ between populations in inshore waters ranged in 0.01-0.05, whereas those of offshore waters ranged in 0.01-0.58. A high gene flow occurred in inshore (Nm=22.61-34.22) and offshore (Nm=11.57-45.67) populations. The distribution of mitochondrial DNA haplotypes between westsouthern and other populations was suggestive of significantly different differentiation ($F_{ST}$=0.20-0.59, p<0.05; d=0.52, p=0.00; ${\phi}=0.02-0.41$, p<0.05). These results suggested that the overall anchovy population in the Korean peninsula caused considerable migration due to the mitochondrial gene flow between inshore and offshore populations to form a genetically homogenous and panmictic structure, although a heterogeneous population was found in this study.