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Baoxiang Wang

Publications and source records attributed to Baoxiang Wang.

At least 91 records · Page 5Linked to original sources
arXiv2018

Beyond Winning and Losing: Modeling Human Motivations and Behaviors Using Inverse Reinforcement Learning

In recent years, reinforcement learning (RL) methods have been applied to model gameplay with great success, achieving super-human performance in various environments, such as Atari, Go, and Poker. However, those studies mostly focus on winning the game and have largely ignored the rich and complex human motivations, which are essential for understanding different players' diverse behaviors. In this paper, we present a novel method called Multi-Motivation Behavior Modeling (MMBM) that takes the multifaceted human motivations into consideration and models the underlying value structure of the players using inverse RL. Our approach does not require the access to the dynamic of the system, making it feasible to model complex interactive environments such as massively multiplayer online games. MMBM is tested on the World of Warcraft Avatar History dataset, which recorded over 70,000 users' gameplay spanning three years period. Our model reveals the significant difference of value structures among different player groups. Using the results of motivation modeling, we also predict and explain their diverse gameplay behaviors and provide a quantitative assessment of how the redesign of the game environment impacts players' behaviors.

cs.LG↗
arXiv2018

Blowup criterion for Navier-Stokes equation in critical Besov space with spatial dimensions $d \geq 4$

This paper is concerned with the blowup criterion for mild solution to the incompressible Navier-Stokes equation in higher spatial dimensions $d \geq 4$. By establishing an $ε$ regularity criterion, we show that if the mild solution $u$ with initial data in $\dot B^{-1+d/p}_{p,q}(\mathbb{R}^d) $, $d<p,\,q<\infty$ becomes singular at a finite time $T_*$, then $$ \limsup_{t\to T_*} \|u(t)\|_{\dot B^{-1+d/p}_{p,q}(\mathbb{R}^d)} = \infty. $$ The corresponding result in 3D case has been obtained by I.Gallagher, G.S.KochandF.Planchon. As a by-product, we also prove a regularity criterion for the Leray-Hopf solution in the critical Besov space, which generalizes the results in~\cite{DoDu09}, where blowup criterion in critical Lebesgue space $L^d(\mathbb{R}^d)$ is obtained.

math.AP↗
arXiv2017

On Dissipative Nonlinear Evolutional Pseudo-Differential Equations

First, using the uniform decomposition in both physical and frequency spaces, we obtain an equivalent norm on modulation spaces. Secondly, we consider the Cauchy problem for the dissipative evolutionary pseudo-differential equation \partial_t u + A(x,D) u = F\big((\partial^α_x u)_{|α|\leq κ}\big), \ \ u(0,x)= u_0(x), where $A(x,D)$ is a dissipative pseudo-differential operator and $F(z)$ is a multi-polynomial. We will develop the uniform decomposition techniques in both physical and frequency spaces to study its local well posedness in modulation spaces $M^s_{p,q}$ and in Sobolev spaces $H^s$. Moreover, the local solution can be extended to a global one in $L^2$ and in $H^s$ ($s>κ+d/2$) for certain nonlinearities.

math.AP↗
arXiv2016

Dynamical Behavior for the Solutions of the Navier-Stokes Equation

We study the Cauchy problem for the incompressible Navier-Stokes equations (NS) in three and higher spatial dimensions: \begin{align} u_t -Δu+u\cdot \nabla u +\nabla p=0, \ \ {\rm div} u=0, \ \ u(0,x)= u_0(x). \label{NSa} \end{align} Leray and Giga obtained that for the weak and mild solutions $u$ of NS in $L^p(\mathbb{R}^d)$ which blow up at finite time $T>0$, respectively, one has that for $d 0$, then \eqref{NSa} has a unique global solution $u\in C(\mathbb{R}_+, L^\infty)$. Finally, if the blowup rate is of type I: $$ \|u(t)\|_p \sim ( T-t )^{-(1-d/p)/2}, \ for \ 0< t<T<\infty, \ d<p<\infty $$ in 3 dimensional case, then we can obtain a minimal blowup solution $Φ$ for which $$ \inf \{\limsup_{t \to T}(T-t)^{(1-3/p)/2}\|u(t)\|_{L^p_x}: \ u\in C([0,T); L^p) \mbox{\ solves \eqref{NSa}}\} $$ is attainable at some $Φ\in L^\infty (0,T; \ \dot B^{-1+6/p}_{p/2,\infty})$.

math.AP↗
arXiv2016

Local Well-Posedness for the Derivative Nonlinear Schrödinger Equations with $L^2$ Subcritical Data

We will show its local well-posedness in modulation spaces $M^{1/2}_{2,q}({\Real})$ $(2\leq q<\infty) $. It is well-known that $H^{1/2}$ is a critical Sobolev space of DNLS so that it is locally well-posedness in $H^s$ for $s\geq 1/2$ and ill-posed in $H^{s'}$ with $s'<1/2.$ Noticing that that $M^{1/2}_{2,q} \subset B^{1/q}_{2,q}$ is a sharp embedding and $L^2 \subset B^0_{2,\infty}$, our result contains all of the subcritical data in $M^{1/2}_{2,q}$, which contains a class of functions in $L^2\setminus H^{1/2}$.

math.AP↗
arXiv2016

Grothendieck-Lidskii trace formula for mixed-norm and variable Lebesgue spaces

In this note we present the metric approximation property for weighted mixed-norm $L_w^{(p_1,\dots ,p_n)}$ and variable exponent Lebesgue type spaces. As a consequence, this also implies the same property for modulation and Wiener-Amalgam spaces. We then characterise nuclear operators on such spaces and state the corresponding Grothendieck-Lidskii trace formulae. We apply the obtained results to derive criteria for nuclearity and trace formulae for periodic operators on $\mathbb R^n$ and functions of the harmonic oscillator in terms of the global symbol.

math.FA↗
arXiv2016

Approximation property and nuclearity on mixed-norm $L^p$, modulation and Wiener amalgam spaces

In this paper we first prove the metric approximation property for weighted mixed-norm $L_w^{(p_1,\dots ,p_n)}$ spaces. Using Gabor frame representation this implies that the same property holds in weighted modulation and Wiener amalgam spaces. As a consequence, Grothendieck's theory becomes applicable, and we give criteria for nuclearity and $r$-nuclearity for operators acting on these space as well as derive the corresponding trace formulae. Finally, we apply the notion of nuclearity to functions of the harmonic oscillator on modulation spaces.

math.FA↗
arXiv2013

Analyticity for the (generalized) Navier-Stokes equations with rough initial data

We study the Cauchy problem for the (generalized) incompressible Navier-Stokes equations \begin{align} u_t+(-Δ)^αu+u\cdot \nabla u +\nabla p=0, \ \ {\rm div} u=0, \ \ u(0,x)= u_0. \nonumber \end{align} We show the analyticity of the local solutions of the Navier-Stokes equation ($α=1$) with any initial data in critical Besov spaces $\dot{B}^{n/p-1}_{p,q}(\mathbb{R}^n)$ with $1< p<\infty, \ 1\le q\le \infty $ and the solution is global if $u_0$ is sufficiently small in $\dot{B}^{n/p-1}_{p,q}(\mathbb{R}^n)$. In the case $p=\infty$, the analyticity for the local solutions of the Navier-Stokes equation ($α=1$) with any initial data in modulation space $M^{-1}_{\infty,1}(\mathbb{R}^n)$ is obtained. We prove the global well-posedness for a fractional Navier-stokes equation ($α=1/2$) with small data in critical Besov spaces $\dot{B}^{n/p}_{p,1}(\mathbb{R}^n) \ (1\leq p\leq\infty)$ and show the analyticity of solutions with small initial data either in $\dot{B}^{n/p}_{p,1}(\mathbb{R}^n) \ (1\leq p<\infty)$ or in $\dot{B}^0_{\infty,1} (\mathbb{R}^n)\cap {M}^0_{\infty,1}(\mathbb{R}^n)$. Similar results also hold for all $α\in (1/2,1)$.

math.AP↗
arXiv2012

Sharp global well-posedness for non-elliptic derivative Schrödinger equations with small rough data

We show the sharp global well posedness for the Cauchy problem for the cubic (quartic) non-elliptic derivative Schrödinger equations with small rough data in modulation spaces $M^s_{2,1}(\mathbb{R}^n)$ for $n\ge 3$ ($n= 2$). In 2D cubic case, using the Gabor frame, we get some time-global dispersive estimates for the Schrödinger semi-group in anisotropic Lebesgue spaces, which include a time-global maximal function estimate in the space $L^2_{x_1}L^\infty_{x_2,t}$. By resorting to the smooth effect estimate together with the dispersive estimates in anisotropic Lebesgue spaces, we show that the cubic hyperbolic derivative NLS in 2D has a unique global solution if the initial data in Feichtinger-Segal algebra or in weighted Sobolev spaces are sufficiently small.

math.AP↗
arXiv2012

$α$-Modulation Spaces (I)

First, we consider some fundamental properties including dual spaces, complex interpolations of $α$-modulation spaces $M^{s,α}_{p,q}$ with $0<p,q \le \infty$. Next, necessary and sufficient conditions for the scaling property and the inclusions between $α_1$-modulation and $α_2$-modulation spaces are obtained. Finally, we give some criteria for $α$-modulation spaces constituting multiplication algebra. As a by-product, we show that there exists an $α$-modulation space which is not an interpolation space between modulation and Besov spaces.

math.FA↗
arXiv2011

Sufficient and Necessary Conditions for the fractional Gagliardo-Nirenberg Inequalities and applications to Navier-Stokes and generalized boson equations

Sufficient and necessary conditions for the generalized Gagliardo-Nirenberg (GN) inequality in Besov spaces and Triebel-Lizorkin spaces are obtained. Applying the GN inequality, we show that the finite-time blowup solutions have concentration phenomena in critical Lebesgue space L^3. Moreover, we consider the minimizer for a class of variational problem by applying the fractional GN inequality.

math.FA↗
arXiv2010

Global well-posedness and scattering for Derivative Schrödinger equation

In this paper we study the Cauchy problem for the elliptic and non-elliptic derivative nonlinear Schrödinger equations in higher spatial dimensions ($n\geq 2$) and some global well-posedness results with small initial data in critical Besov spaces $B^s_{2,1}$ are obtained. As by-products, the scattering results with small initial data are also obtained.

math.AP↗
arXiv2010

Local well posedness for KdV with data in a subspace of $H^{-1}$ and applications to illposedness theory for KdV and mKdV

We prove the local well posedness for the KdV equation in the modulation space $M^{-1}_{2,1}(\mathbb{R})$. Our method is to substitute the dyadic decomposition by the uniform decomposition in the discrete Bourgain space. This wellposedness result enables us to show that the solution map is discontinuous at the origin with respect to the $H^{s} $-topology as soon as $s<-1$. Making use of the Miura transform we also deduce a discontinuity result for the $ H^s(\Real) $-topology, $s<0 $, for the solution map associated with the focussing and defocussing mKdV equations.

math.AP↗
arXiv2010

Neutron spectroscopic factors of 7Li and astrophysical 6Li(n,g)7Li reaction rates

Angular distributions of the 7Li(6Li,6Li)7Li elastic scattering and the 7Li(6Li,7Li_{g.s.})6Li, 7Li(6Li,7Li*_{0.48})6Li transfer reactions at Ec.m. = 23.7 MeV were measured with the Q3D magnetic spectrograph. The optical potential of 6Li+7Li was obtained by fitting the elastic scattering differential cross sections. Based on the distorted wave Born approximation (DWBA) analysis, spectroscopic factors of 7Li=6Li+n were determined to be 0.73 +- 0.05 and 0.90 +- 0.09 for the ground and first exited states in 7Li, respectively. Using the spectroscopic factors, the cross sections of the 6Li(n,g)7Li direct neutron capture reactions and the astrophysical 6Li(n,g)7Li reaction rates were derived.

nucl-ex↗
arXiv2009

On the local regularity of the KP-I equation in anisotropic Sobolev space

We prove that the KP-I initial-value problem \begin{eqnarray*} \begin{cases} \partial_tu+\partial_x^3u-\partial_x^{-1}\partial_y^2u+\partial_x(u^2/2)=0 {on}{\R}^2_{x,y}\times {\R}_t; u(x,y,0)=ϕ(x,y), \end{cases} \end{eqnarray*} is locally well-posed in the space \begin{eqnarray*} H^{1,0}(\R^2)=\{ϕ\in L^2(\R^2): \ \normϕ_{H^{1,0}(\R^2)}\approx\normϕ_{L^2}+\norm{\partial_xϕ}_{L^2}<\infty\}. \end{eqnarray*}

math.AP↗