• Title/Summary/Keyword: measurable coefficients

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NOTE ON LOCAL BOUNDEDNESS FOR WEAK SOLUTIONS OF NEUMANN PROBLEM FOR SECOND-ORDER ELLIPTIC EQUATIONS

  • KIM, SEICK
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.19 no.2
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    • pp.189-195
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    • 2015
  • The goal of this note is to provide a detailed proof for local boundedness estimate near the boundary for weak solutions for second order elliptic equations with bounded measurable coefficients subject to Neumann boundary condition.

NOTE ON LOCAL ESTIMATES FOR WEAK SOLUTION OF BOUNDARY VALUE PROBLEM FOR SECOND ORDER PARABOLIC EQUATION

  • Choi, Jongkeun
    • Bulletin of the Korean Mathematical Society
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    • v.53 no.4
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    • pp.1123-1148
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    • 2016
  • The aim of this note is to provide detailed proofs for local estimates near the boundary for weak solutions of second order parabolic equations in divergence form with time-dependent measurable coefficients subject to Neumann boundary condition. The corresponding parabolic equations with Dirichlet boundary condition are also considered.

THE BOUNDARY HARNACK PRINCIPLE IN HÖLDER DOMAINS WITH A STRONG REGULARITY

  • Kim, Hyejin
    • Bulletin of the Korean Mathematical Society
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    • v.53 no.6
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    • pp.1741-1751
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    • 2016
  • We prove the boundary Harnack principle and the Carleson type estimate for ratios of solutions u/v of non-divergence second order elliptic equations $Lu=a_{ij}D_{ij}+b_iD_iu=0$ in a bounded domain ${\Omega}{\subset}R_n$. We assume that $b_i{\in}L^n({\Omega})$ and ${\Omega}$ is a $H{\ddot{o}}lder$ domain of order ${\alpha}{\in}$ (0, 1) satisfying a strong regularity condition.

A MAXIMUM PRINCIPLE FOR NON-NEGATIVE ZEROTH ORDER COEFFICIENT IN SOME UNBOUNDED DOMAINS

  • Cho, Sungwon
    • Korean Journal of Mathematics
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    • v.26 no.4
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    • pp.747-756
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    • 2018
  • We study a maximum principle for a uniformly elliptic second order differential operator in nondivergence form. We allow a bounded positive zeroth order coefficient in a certain type of unbounded domains. The results extend a result by J. Busca in a sense of domains, and we present a simple proof based on local maximum principle by Gilbarg and Trudinger with iterations.

Effects of solution, sorbate, and sorbent chemistries on polycyclic aromatic hydrocarbon sorption to hydrated mineral surfaces

  • Yim, Soobin
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.132-135
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    • 2003
  • Solution chemistry, sorbate chemistry, and sorbent chemistry were widely investigated to find important factors that affect PAH sorption on mineral surfaces and to elucidate its microscopic mechanism. The solution chemistry, pH and ionic strength caused measurable change of HOC sorption reaction to minerals. The detectable change of Ka occurred at a pH region crossing the PZC (Point of Zero Charge) of each mineral. The PAH hydrophobicity, one of sorbate chemistry, was observed to have a strong correlation with PAM sorption to mineral. Mineral surface area was not found to be a predominant factor controlling PAH sorption. The mineral type might be more likely to play a crucial role in controlling the PAH sorption behavior. The CEC (Cation Exchange Capacity) of mineral, representing surface charge density, has meaningful correlation with regression slope of sorption coefficients (log $K_{d}$) versus aqueous activity coefficients (log Υ$_{w}$).).).

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Dissociative Recombination Rates of O₂+ Ion with Low Energy Electrons

  • 성정희;선호성
    • Bulletin of the Korean Chemical Society
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    • v.17 no.11
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    • pp.1065-1073
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    • 1996
  • The dissociative recombination of O2+(v+)+e-→O(1S)+O(1D) has been theoretically investigated using the multichannel quantum defect theory (MQDT). Cross sections and rate coefficients at various electron energies are calculated. The resonant structures in cross section profile, which are hardly measurable in experiments, are also determined and the existence of Rydberg states is found to affect the rates. The theoretical rate coefficients are computed to be smaller than experimental ones. The reasons for this difference are explained. The two-step MQDT procedure is found to be very useful and promising in calculating the state-to-state rates of the dissociative recombination reaction which is a very important and frequently found phenomenon in Earth's ionosphere.

Estimation of the Unmeasured Unbalance Responses and Identification of Bearing Parameters in Flexible Rotor-Bearing Systems (회전체 베어링계의 불균형응답 간접추정과 베어링 매개변수 규명)

  • 홍성욱;이종원
    • Journal of KSNVE
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    • v.2 no.3
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    • pp.193-202
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    • 1992
  • The unbalance response analysis is one of the essential area in the forced vibration analysis of rotor bearing systems because of it usefulness in balancing and diagnosis as well as identification of parameters involved in rotor bearing systems. However some unbalance responses are not measurable due to the fact that rotor bearing systems are often encapsulated by fixtures or safety protectors. In the present paper, an efficent estimation scheme for unmeasured unbalance responses in rotor bearing systems is developed. The fundamental fearture of the proposed method is characterized by the linear formulae to estimate the unbalance responses from the measured unbalance responses and the finite element auxilliary model equation which is constructed to be identical to the prototype excluding the uncertain parameters such as bearing coefficients. The identification formulae for bearing parameters are also derived by using the unbalance response and the finite elements auxiliary model. Simulation is provided to verify the effectiveness of the proposed method.

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A Study on Calculating Relevant Length of Left Turn Storages Using UAV Spatial Images Considering Arrival Distribution Characteristics at Signalized Intersections in Urban Commercial Areas

  • Yang, Jaeho;Kim, Eungcheol;Na, Young-Woo;Choi, Byoung-Gil
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.3
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    • pp.153-164
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    • 2018
  • Calculating the relevant length of left turn storages in urban intersections is very crucial in road designs. A left turn lane consists of deceleration lanes and left turn storages. In this study, we developed methods for calculating relevant lengths of left turn storages that vary at each intersection using UAV (Unmanned Aerial Vehicle) spatial images. Problems of conventional design techniques are applying the same number of left turn vehicles (N) using Poisson distribution without considering land use types, using a vehicle length that may not be measurable when applying the length of waiting vehicles (S), and using same storage length coefficient (${\alpha}$), 1.5, for every intersections. In order to solve these problems, we estimated the number of left turn vehicles (N) using an empirical distribution, suggested to use headways of vehicles for (S) to calculate the length of waiting vehicles (S) with a help of using UAV spatial images, and defined ranges of storage length coefficient (${\alpha}$) from 1.0 to 1.5 for flexible design. For more convenient design, it is suitable to classify two cases when possible to know and impossible to know about ratio of large trucks among vehicles when planning an intersection. We developed formula for each case to calculate left turn storage lengths of a minimum and a maximum. By applying developed methods and values, more efficient signalized intersection operation can be accomplished.