Existence and general decay for nondissipative distributed systems with boundary frictional and memory dampings and acoustic boundary conditions

In this paper, we study the existence and general energy decay rate of global solutions for nondissipative distributed systems

$$u''-\triangle u+h(\nabla u)=0$$

with boundary frictional and memory dampings and acoustic boundary conditions. For the existence of solutions, we prove the global existence of weak solution by using Faedo–Galerkin’s method and compactness arguments. For the energy decay rate, we first consider the general nonlinear case of h satisfying a smallness condition and prove the general energy decay rate by using perturbed modified energy method. Then, we consider the linear case of h: \({h(\nabla u)=-\nabla\phi\cdot\nabla u}\) and prove the general decay estimates of equivalent energy.

     

Some borderline cases of nonlinear parabolic equations with irregular data

In this paper, we prove existence of solutions for nonlinear parabolic equations whose model is

$$u' - {\rm div} \, (|\nabla u|^{p-2}\nabla u) = f \quad {\rm on} \, \Omega \times (0,T),$$

with homogeneous Cauchy–Dirichlet boundary conditions, where \({1 < p < 2}\). Here f belongs to L ¹ or to L ^m , with m “small.”

     

The existence of solutions for boundary value problems of two types fractional perturbation differential equations

In this paper, we study the existence of solutions for the boundary value problems of fractional perturbation differential equations

$$\begin{aligned} D^{\alpha }\left( \frac{x(t)}{f(t,x(t))}\right) =g(t,x(t)),\;\;a.e.\;t\in J=[0,1], \end{aligned}$$

or

$$\begin{aligned} D^{\alpha }\left( x(t)-f(t,x(t))\right) =g(t,x(t)),\;\;a.e.\;t\in J, \end{aligned}$$

subject to

$$\begin{aligned} x(0)=y(x),\;\;x(1)=m, \end{aligned}$$

where \(1<\alpha <2,\,D^{\alpha }\) is the standard Caputo fractional derivatives. Using some fixed point theorems, we prove the existence of solutions to the two types. For each type we give an example to illustrate our results.

     

Chains of saturated models in AECs

We study when a union of saturated models is saturated in the framework of tame abstract elementary classes (AECs) with amalgamation. We prove:

Theorem 0.1. If K is a tame AEC with amalgamation satisfying a natural definition of superstability (which follows from categoricity in a high-enough cardinal), then for all high-enough \(\lambda {:}\)

1. (1)
   The union of an increasing chain of \(\lambda \)-saturated models is \(\lambda \)-saturated.
    
2. (2)
   There exists a type-full good \(\lambda \) -frame with underlying class the saturated models of size \(\lambda \).
    
3. (3)
   There exists a unique limit model of size \(\lambda \).
    

Our proofs use independence calculus and a generalization of averages to this non first-order context.

     

Linear Programming in Air Defence Modelling

The paper describes the use of an optimizing model, together with a simulation model, to determine the most effective mix and deployment of air defence weapons to defend a given set of assets against a range of air threats. The advantages of using an optimizing model in such studies are that it:

1. a
   —Gives more consistent results by reducing player variance.
    
2. b
   —Can generate solutions that are robust to variations in threat and environment.
    
3. c
   —Ensures that good solutions are not overlooked.
    
4. d
   —Reduces the total processing time required to complete the study.
    

     

Semilinear equations with exponential nonlinearity and measure data

We study the existence and non-existence of solutions of the problem

(0.1)

where Ω is a bounded domain in , N3, and μ is a Radon measure. We prove that if , then (0.1) has a unique solution. We also show that the constant 4π in this condition cannot be improved.     

Local uniqueness and periodicity for the prescribed scalar curvature problem of fractional operator in $${\mathbb {R}}^{N}$$

Consider the following prescribed scalar curvature problem involving the fractional Laplacian with critical exponent:

$$\begin{aligned} \left\{ \begin{array}{ll}(-\Delta )^{\sigma }u=K(y)u^{\frac{N+2\sigma }{N-2\sigma }} \text { in }~ {\mathbb {R}}^{N},\\ ~u>0, \quad y\in {\mathbb {R}}^{N}.\end{array}\right. \end{aligned}$$

(0.1)

For \(N\ge 4\) and \(\sigma \in (\frac{1}{2}, 1),\) we prove a local uniqueness result for bubbling solutions of (0.1). Such a result implies that some bubbling solutions preserve the symmetry from the scalar curvature K(y).

     

Robust solutions and risk measures for a supply chain planning problem under uncertainty

We consider a strategic supply chain planning problem formulated as a two-stage stochastic integer programming (SIP) model. The strategic decisions include site locations, choices of production, packing and distribution lines, and the capacity increment or decrement policies. The SIP model provides a practical representation of real-world discrete resource allocation problems in the presence of future uncertainties which arise due to changes in the business and economic environment. Such models that consider the future scenarios (along with their respective probabilities) not only identify optimal plans for each scenario, but also determine a hedged strategy for all the scenarios. We

1. 1)
   exploit the natural decomposable structure of the SIP problem through Benders’ decomposition,
    
2. 2)
   approximate the probability distribution of the random variables using the generalized lambda distribution, and
    
3. 3)
   through simulations, calculate the performance statistics and the risk measures for the two models, namely the expected-value and the here-and-now.
    

     

Infinitely many non-negative solutions for a Dirichlet problem involving -Laplacian

In this paper, we consider a Dirichlet problem involving the p(x)-Laplacian of the type

We prove the existence of infinitely many non-negative solutions of the problem by applying a general variational principle due to B. Ricceri and the theory of the variable exponent Sobolev spaces.     

Periodic solutions of a semilinear elliptic equation with a fractional Laplacian

We consider periodic solutions of the following problem associated with the fractional Laplacian

$$(-\partial _{xx})^s u(x) + F'(u(x))=0,\quad u(x)=u(x+T),\quad \text{ in } \, \mathbb {R}, $$

where \((-\partial _{xx})^s\) denotes the usual fractional Laplace operator with \(0<s<1\). The primitive function F of the nonlinear term is a smooth double-well potential. We prove the existence of periodic solutions with large period T using variational methods. An estimate of the energy of the periodic solutions is also established.

     

Models for use in Negotiations on Pay and Working Conditions

In this paper we develop three inter-related models, based on value added concepts, that can form the starting point for discussions on pay and working conditions at the plant level. The first model considers the factors that contribute to an increase in the added value (such as prices, sales volume and material productivity) and provides a relationship between relative changes in the values of these factors and the resulting relative change in the added value. In the second model the increase in the added value is assumed to be shared between the labourforce (through increased wages) and the management (who require funds to cover all other costs and make provision for profit); the relative change in wages is decomposed further to take into consideration the effect on the average employee's pay of possible changes in the labour productivity and/or the size of the workforce. The two models are then combined to produce the third model with a view to rewarding labour and management in proportion to each one's contribution towards improving the operational efficiency of the plant.All three models are simple and versatile enough to allow:

1. a)
   The use of alternative assumptions and functional relationships to reflect differing views of the negotiators;
    
2. b)
   sensitivity analyses to identify the most crucial assumptions and estimates that are likely to affect the results; and
    
3. c)
   further disaggregation to incorporate additional variables and a more detailed breakdown of the added value, wage rates or working hours, if this is thought to be desirable.
    

It is recommended that such models be developed, discussed and analysed by the negotiators themselves in an attempt to make them highlight the issues, arguments and important characteristics pertaining in each individual case. The models could then provide the basis of a common communication language leading to a better understanding of each other's position and, hopefully, to less conflict.     

Ground State Solutions for a Quasilinear Schrödinger Equation

In this paper, we study the following quasilinear Schrödinger equation of the form

$$\begin{aligned} -\Delta u+V(x)u-\Delta (u^{2})u= g(x,u),~~~ x\in \mathbb {R}^N \end{aligned}$$

where V and g are 1-periodic in \(x_{1},\ldots ,x_{N}\), and g is a superlinear but subcritical growth as \(|u|\rightarrow \infty \). We develop a more direct and simpler approach to prove the existence of ground state solutions.

     

Aubry–Mather Sets for Relativistic Oscillators with Anharmonic Potentials

In this paper, by the Aubry–Mather theory, it is proved that there are many periodic solutions and usual or generalized quasiperiodic solutions for relativistic oscillator with anharmonic potentials models d/dt(x/(1-|x|~2~(1/2))+ |x|~(α-1)x=p(t),where p(t) ∈ C~0(R~1) is 1-periodic and α 0.     

Weighted polyharmonic equation with Navier boundary conditions in a half space

We study positive solutions of the following polyharmonic equation with Hardy weights associated to Navier boundary conditions on a half space:?????(-?)~mu(x)=u~p(x)/|x|~s,in R_+~n,u(x)=-?u(x)=…=(-?)~(m-1)u(x)=0,on ?R_+~n,(0.1)where m is any positive integer satisfying 02mn.We first prove that the positive solutions of(0.1)are super polyharmonic,i.e.,(-?)~iu0,i=0,1,...,m-1.(0.2) For α=2m,applying this important property,we establish the equivalence between (0.1) and the integral equation u(x)=c_n∫R_+~n(1/|x-y|~(n-α)-1/|x~*-y|~(n-α))u~p(y)/|y|~sdy,(0.3) where x~*=(x1,...,x_(n-1),-x_n) is the reflection of the point x about the plane R~(n-1).Then,we use the method of moving planes in integral forms to derive rotational symmetry and monotonicity for the positive solution of(0.3),in whichαcan be any real number between 0 and n.By some Pohozaev type identities in integral forms,we prove a Liouville type theorem—the non-existence of positive solutions for(0.1).     

Infinitely many solutions for a nonlinear Schrödinger equation with general nonlinearity

We prove the existence of infinitely many solutions for

$$\begin{aligned} - \Delta u + V(x) u = f(u) \quad \text { in } \mathbb {R}^N, \quad u \in H^1(\mathbb {R}^N), \end{aligned}$$

where V(x) satisfies \(\lim _{|x| \rightarrow \infty } V(x) = V_\infty >0\) and some conditions. We require conditions on f(u) only around 0 and at \(\infty \).

     

Symmetry breaking of an elliptic equation in expanding annuli

We obtain non-radial bifurcation from radial solutions of a semilinear elliptic equation in expanding annuli of \(\mathbb {R}^N\). To obtain the main results, we use a blow-up argument via the Morse index of the regular entire solutions of the equation

$$\begin{aligned} -\Delta u=\lambda u^p \quad \text {in}\quad \mathbb {R}^N. \end{aligned}$$

(0.1)

The main results of this paper can be seen as applications of the properties of regular entire solutions of (0.1).

     

Blow-up of positive-initial-energy solutions of a nonlinear viscoelastic hyperbolic equation

In this paper, we consider the nonlinear viscoelastic equation

with initial conditions and Dirichlet boundary conditions. For nonincreasing positive functions g and for p>m, we prove that there are solutions with positive initial energy that blow up in finite time.     

Maximal monotone operator theory and its applications to thin film equation in epitaxial growth on vicinal surface

In this work we consider

$$\begin{aligned} w_t=\left[ \left( w_{hh}+c_0\right) ^{-3}\right] _{hh},\qquad w(0)=w^0, \end{aligned}$$

(1)

which is derived from a thin film equation for epitaxial growth on vicinal surface. We formulate the problem as the gradient flow of a suitably-defined convex functional in a non-reflexive space. Then by restricting it to a Hilbert space and proving the uniqueness of its sub-differential, we can apply the classical maximal monotone operator theory. The mathematical difficulty is due to the fact that \(w_{hh}\) can appear as a positive Radon measure. We prove the existence of a global strong solution with hidden singularity. In particular, (1) holds almost everywhere when \(w_{hh}\) is replaced by its absolutely continuous part.

     

An Integrated Framework for Generating and Revising Factory Schedules

Practical solutions to the production scheduling problem must provide two broad capabilities:

1. i)
   an ability to efficiently generate schedules that reflect the actual constraints and objectives of the manufacturing environment, and
    
2. ii)
   an ability to incrementally revise these schedules over time in response to unexpected executional circumstances. In this paper, we advocate a common view of predictive and reactive scheduling as an incremental problem solving process that is opportunistically focused by characteristics of the current solution constraints.
    

We describe the architecture of OPIS (opportunistic intelligent scheduler), which defines a general framework for configuring scheduling systems according to this view. We then examine the scheduling knowledge (e.g. analysis and scheduling methods, schedule generation or revision strategies) that is exploited within this architecture by the current OPIS scheduler. Experimental studies with the OPIS scheduler have demonstrated the potential of this constraint-directed scheduling methodology in both predictive and reactive scheduling contexts.