POSITIVE SOLUTIONS AND BIFURCATION OF FULLY NONLINEAR ELLIPTIC EQUATIONS INVOLVING SUPER－CRITICAL SOBOLEV EXPONENTS

ＰＯＳＩＴＩＶＥＳＯＬＵＴＩＯＮＳＡＮＤＢＩＦＵＲＣＡＴＩＯＮＯＦＦＵＬＬＹＮＯＮＬＩＮＥＡＲＥＬＬＩＰＴＩＣＥＱＵＡＴＩＯＮＳＩＮＶＯＬＶＩＮＧＳＵＰＥＲ－ＣＲＩＴＩＣＡＬＳＯＢＯＬＥＶＥＸＰＯＮＥＮＴＳ￥ＱＵＣＨＡＮＧＺＨＥＮＧ（屈长征）（Ｉｎｓ...     

FORCED OSCILLATIONS OF HYPERBOLIC DIFFERENTIAL EQUATIONS WITH DEVIATING ARGUMENTS

ＦＯＲＣＥＤＯＳＣＩＬＬＡＴＩＯＮＳＯＦＨＹＰＥＲＢＯＬＩＣＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＤＥＶＩＡＴＩＮＧＡＲＧＵＭＥＮＴＳＣＵＩＢＡＯＴＯＮＧ（崔宝同）（ＢｉｎｚｈｏｕＮｏｒｍａｌＣｏｌｌｅｇｅ，Ｂｉｎｚｈｏｕ２５６６０４，Ｃ...     

ON GLOBAL SOLUTION FOR A CLASS OF SYSTEMS OF MULTI－DIMENSIONAL GENERALIZED ZAKHAROV TYPE EQUATION

ＯＮＧＬＯＢＡＬＳＯＬＵＴＩＯＮＦＯＲＡＣＬＡＳＳＯＦＳＹＳＴＥＭＳＯＦＭＵＬＴＩ－ＤＩＭＥＮＳＩＯＮＡＬＧＥＮＥＲＡＬＩＺＥＤＺＡＫＨＡＲＯＶＴＹＰＥＥＱＵＡＴＩＯＮＧＵＯＢＯＬＩＮＧ（郭柏灵）（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄａｎｄＣｏｍｐｕ...     

EXISTENCE AND UNIQUENESS OF SOLUTIONS FOR NONLINEAR BOUNDARY VALUE PROBLEMS OF VOLTERRA－HAMMERSTEIN TYPE INTEGRODIFFERENTIAL EQUATION

ＥＸＩＳＴＥＮＣＥＡＮＤＵＮＩＱＵＥＮＥＳＳＯＦＳＯＬＵＴＩＯＮＳＦＯＲＮＯＮＬＩＮＥＡＲＢＯＵＮＤＡＲＹＶＡＬＵＥＰＲＯＢＬＥＭＳＯＦＶＯＬＴＥＲＲＡ－ＨＡＭＭＥＲＳＴＥＩＮＴＹＰＥＩＮＴＥＧＲＯＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮ￥ＷａｎｇＧ...     

CONVERGENCE AND STABILITY OF SOLUTIONSOF CERTAIN INFINITE DELAY DIFFERENTIAL EQUATIONS

ＣＯＮＶＥＲＧＥＮＣＥＡＮＤＳＴＡＢＩＬＩＴＹＯＦＳＯＬＵＴＩＯＮＳＯＦＣＥＲＴＡＩＮＩＮＦＩＮＩＴＥＤＥＬＡＹＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳ￥ＺｈｅｎｇＢｕｎａｎ＆ＣｈｅｎＷｕｈｕａ＆ＬｕｏＧｕｉｌｉｅ（ＧｕａｎｇｘｉＮｏｒｍａｌＵｎｉ...     

A NOTE OF UNIFORM EXPONENTIAL STABILIZATION FOR NONCONTRACTIVE SEMIGROUPS UNDER COMPACT PERTURBATION

ＡＮＯＴＥＯＦＵＮＩＦＯＲＭＥＸＰＯＮＥＮＴＩＡＬＳＴＡＢＩＬＩＺＡＴＩＯＮＦＯＲＮＯＮＣＯＮＴＲＡＣＴＩＶＥＳＥＭＩＧＲＯＵＰＳＵＮＤＥＲＣＯＭＰＡＣＴＰＥＲＴＵＲＢＡＴＩＯＮＳｏｎｇＧｕｏｚｈｕ（宋国柱）（Ｄｅｐｔ．ｏｆＭａｔｈ．，Ｎａｎｊｉｎｇ...     

CONVERGENCE AND STABILITY OF SOLUTIONS OF CERTAIN INFINITE DELAY DIFFERENTIAL EQUATIONS

ＣＯＮＶＥＲＧＥＮＣＥＡＮＤＳＴＡＢＩＬＩＴＹＯＦＳＯＬＵＴＩＯＮＳＯＦＣＥＲＴＡＩＮＩＮＦＩＮＩＴＥＤＥＬＡＹＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＣｈｅｎＷｕｈｕａ（ＧｕａｎｇＸｉＮａｔｉｏｎａｌＩｎｓｔｉｔｕｔｅ，Ａｂｓｔｒａｃｔ：ＢｙＣｏ...     

ON THE GLOBAL ATTRACTIVITY FOR A NEUTRAL DIFFERENCE EQUATION WITH TWO DELAYS

ＯＮ　ＴＨＥ　ＧＬＯＢＡＬ　ＡＴＴＲＡＣＴＩＶＩＴＹ　ＦＯＲ　Ａ　ＮＥＵＴＲＡＬ　ＤＩＦＦＥＲＥＮＣＥ　ＥＱＵＡＴＩＯＮ　ＷＩＴＨ　ＴＷＯ　ＤＥＬＡＹＳＯＮＴＨＥＧＬＯＢＡＬＡＴＴＲＡＣＴＩＶＩＴＹＦＯＲＡＮＥＵＴＲＡＬＤＩＦＦＥＲＥＮＣＥＥＱＵＡＴ...     

INVERSE SCATTERING TRANSFORMATION FOR THE VARIABLE COEFFICIENT SINE－GORDON TYPE EQUATION

ＩＮＶＥＲＳＥＳＣＡＴＴＥＲＩＮＧＴＲＡＮＳＦＯＲＭＡＴＩＯＮＦＯＲＴＨＥＶＡＲＩＡＢＬＥＣＯＥＦＦＩＣＩＥＮＴＳＩＮＥ－ＧＯＲＤＯＮＴＹＰＥＥＱＵＡＴＩＯＮＸＵＢＡＯＺＨＩＡＮＤＺＨＡＯＳＨＥＮＱＩＡｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐｅｒ，ｔｈｅｖ...     

广义Chebyshev－Vandermonde方程组的快速算法与求逆公式

广义Ｃｈｅｂｙｓｈｅｖ－Ｖａｎｄｅｒｍｏｎｄｅ方程组的快速算法与求逆公式成礼智（国防科技大学）ＩＮＥＲＳＩＯＮＦＯＲＭＵＬＡＡＮＤＦＡＳＴＳＯＬＵＴＩＯＮＦＯＲＧＥＮＥＲＡＬＣＨＥＢＹＳＨＥＶ－ＶＡＮＤＥＲＭＯＮＤＥＥＱＵＡＴＩＯＮＳ￥ＣｈｅｎｇＬｉ...     

A Study on Abnormality in Variational and Optimal Control Problems

In this paper, a variational problem is considered with differential equality constraints over a variable interval. It is stressed that the abnormality is a local character of the admissible set; consequently, a definition of regularity related to the constraints characterizing the admissible set is given. Then, for the local minimum necessary conditions, a compact form equivalent to the well-known Euler equation and transversality condition is given. By exploiting this result and the previous definition of regularity, it is proved that nonregularity is a necessary and sufficient condition for an admissible solution to be an abnormal extremal. Then, a necessary and sufficient condition is given for an abnormal extremal to be weakly abnormal. The analysis of the abnormality is completed by considering the particular case of affine constraints over a fixed interval: in this case, the abnormality turns out to have a global character, so that it is possible to define an abnormal problem or a normal problem. The last section is devoted to the study of an optimal control problem characterized by differential constraints corresponding to the dynamics of a controlled process. The above general results are particularized to this problem, yielding a necessary and sufficient condition for an admissible solution to be an abnormal extremal. From this, a previously known result is recovered concerning the linearized system controllability as a sufficient condition to exclude the abnormality.     

A Chart for Evaluating Product Research and Development Projects

A method of evaluating research and development projects is described. The method is based on the use of an evaluation chart. The main purpose of the chart is to calculate a project score which is a measure of a selected evaluation criterion. A method of constructing a chart is illustrated using a project index as the evaluation criterion. The chart contains a list of twelve questions, the answers to which are assumed to be the main determinants of the variables in the formula of the index. Each question is followed by a set of answers from which a choice is to be made, and underneath each answer is a numerical score. The numerical scores are logarithmic functions of the answers to which they relate, and when added together give a project score which is a logarithmic function of the index. Various methods of using the chart, and a suggested evaluation procedure, are also described.     

Interface of global and local semantics in a self-navigating system based on the concept lattice

If the syntax–semantics interaction is driven by the interface, it also interrupts the interaction on its own right. Because the syntax is verified to be isomorphic to the semantics, the interaction is open to the diagonal argument leading to a contradiction. That is why it is necessary to introduce a particular interface to drive the interface to make the interaction possible despite the contradiction. In this context we propose the system implemented with the syntax–semantics loop by using a concept lattice and a particular weak quantifier. This system is expressed as the self-navigating system which wanders in a two-dimensional space, encounters some landmarks, constructs the relationship among landmarks to which decision making with respect to the move is referred. The syntax of this system is defined as two-dimensional move and the semantics is defined as a concept lattice [B. Ganter, R. Wille, Formal Concept Analysis, Springer, Berlin, 1999] constructed by the binary relation between landmarks and some properties of landmarks, and by Galois connection. To implement the interface driving and interrupting the interaction between syntax and semantics, we divided semantics into local and global concept lattices, and introduce a weak quantifier to connect a local with a global lattice. Because the contradiction results from diagonal argument or using a normal quantifier ∀, the use of a quantifier is restricted dependent on the situation to avoid a contradiction. It is shown that due to the role of a weak quantifier our self-navigating system is both robust and open to the emergent property through simulating studies.     

Optimal pricing and quantity of products with two offerings

This paper analyzes the decision of a firm offering two versions of a product, a deluxe and a regular. While both products satisfy the same market, the deluxe version is sold at a high price relative to its cost and is aimed at the high end of the demand curve. The regular version is sold at a low price relative to its cost and is targeted to customers at the low end of the demand curve. This two-offering strategy is especially popular with book publishers where a paperback book is introduced some time after the hardbound version is introduced. The time between the introduction of the two versions of the product is accompanied by a downward shift in the demand curve due to customers losing interest in the product or satisfying their demand from a secondary used market. We solve a profit maximization model for a firm using a two-offering strategy. The model is solved for linear and exponential deterioration in demand, which is assumed to be deterministic. Also, a model with linear deterioration in demand, which is assumed to be stochastic, is solved. The results indicate that substantial improvements in profit can be obtained by using the two-offering strategy. Numerical sensitivity analysis and examples are used to illustrate the results.     

Evolution to a steady state for a rarefied gas flowing from a tank into a vacuum through a plane channel

A kinetic equation (S-model) is used to solve the nonstationary problem of a monatomic rarefied gas flowing from a tank of infinite capacity into a vacuum through a long plane channel. Initially, the gas is at rest and is separated from the vacuum by a barrier. The temperature of the channel walls is kept constant. The flow is found to evolve to a steady state. The time required for reaching a steady state is examined depending on the channel length and the degree of gas rarefaction. The kinetic equation is solved numerically by applying a conservative explicit finite-difference scheme that is firstorder accurate in time and second-order accurate in space. An approximate law is proposed for the asymptotic behavior of the solution at long times when the evolution to a steady state becomes a diffusion process.     

Bidding under price uncertainty in multi-unit pay-as-bid procurement auctions for power systems reserve

In this paper a methodology for profit maximized bidding under price uncertainty in a day-ahead, multi-unit and pay-as-bid procurement auction for power systems reserve is proposed. Within this novel methodology a bidder is considered to follow a Bayes-strategy. Thereby, one bidder is assumed to behave strategically and the behavior of the remaining is summarized in a probability distribution of the market price and a reaction function to price dumping by the strategic bidder. With this approach two problems arise: First, as a pay-as-bid auction is considered, no uniform price and therefore no single probability distribution of the market price is readily available. Second, if historic bidding data of all participants are used to estimate such a distribution and market power is a relevant factor, the bid of the strategically behaving bidder is likely to influence the distribution. Within this paper for both of the problems solutions are presented. It is shown that by estimating a probability of acceptance the optimal bidding price with respect to a given capacity can be calculated by maximizing a stochastic non-linear objective function of expected profit. Taking the characteristics of recently established markets in Germany into account, the methodology is applied using exemplary data. It is shown that the methodology helps to manage existing price uncertainties and hence supports the trading decisions of a bidder. It is inferred that the developed methodology may also be used for bidding on other auction markets with a similar market design.     

Perspectives sur les recherches en didactique des mathématiques

The paper is a review of chosen approaches to research in mathematics education in several countries: Germany, France, United States, Russia, Poland, Canada. The review is done in the literary form of a satire, in which a character is taken on a voyage to a variety of “islands” respresenting different research interests and methodologies in mathematics education. The story is a parody of Homer’sOdyssee, and the main character is called Odysseus. Odysseus’ role is played by the famous arithmetic problem about a team of an unknown number of scythers who are given the task of scything two meadows one of which is double the size of the other. As the problem travels from one “island” to another, mathematics educators do different things to and with the problem and it is solved is a variety of ways. The main text of the paper reads as a story and there are no explicit references and names of authors, whose work is only alluded to. However, the solution to all allusions, i.e. explicit references, can be found in the footnotes.     

Persistence Terrace for Topological Inference of Point Cloud Data

Topological data analysis (TDA) is a rapidly developing collection of methods for studying the shape of point cloud and other data types. One popular approach, designed to be robust to noise and outliers, is to first use a smoothing function to convert the point cloud into a manifold and then apply persistent homology to a Morse filtration. A significant challenge is that this smoothing process involves the choice of a parameter and persistent homology is highly sensitive to that choice; moreover, important scale information is lost. We propose a novel topological summary plot, called a persistence terrace, that incorporates a wide range of smoothing parameters and is robust, multi-scale, and parameter-free. This plot allows one to isolate distinct topological signals that may have merged for any fixed value of the smoothing parameter, and it also allows one to infer the size and point density of the topological features. We illustrate our method in some simple settings where noise is a serious issue for existing frameworks and then we apply it to a real dataset by counting muscle fibers in a cross-sectional image. Supplementary material for this article is available online.     

Nonlinear breathing crack identification from time-domain sensitivity analysis

Breathing cracks are often encountered in engineering structures and detection of such cracks at the earliest stage is important for safety and serviceability of the structures. In this paper, a new breathing crack identification approach based on the time-domain sensitivity analysis is proposed. For the forward problem, the crack is simply treated as a nonlinear oscillator and how to model a structure with breathing cracks is specified. As regards the inverse crack identification, it is formulated as a nonlinear least-squares optimization problem and a new sensitivity-based approach is developed to get the solution. In doing so, the sensitivity analysis of the possibly non-differentiable breathing crack models is necessarily proceeded through a smoothing strategy. Moreover, to enhance the convergence, the trust-region constraint is introduced and the Tikhonov regularization is naturally called to tackle the constraint. Numerical examples are studied to verify the feasibility and efficiency of the proposed approach in breathing crack identification.     

On Two-Phase Flow in a Rotating Boundary Layer

The two-phase flow induced by a rotating disk in a stationary unbounded mixture is considered. The generalized similarity assumption of von Karman reduces the averaged equations of motion with a linear drag between the phases to a system of ordinary differential equations. These are investigated by asymptotic and numerical techniques. The equations display a nontrivial behavior in a sublayer near the boundary, whose thickness is of the order of the particle size. The volume fraction of the dispersed phase is singular unless a small suction is applied on the disk or a small diffusion term is added to the continuity equations. Outside this sublayer, the velocity field is quite similar to a rescaled classical von Karman flow. Good agreement between asymptotic and numerical solution is obtained, although there is considerable stiffness in the equations. The motion of a solid particle in a von Karman flow is also discussed, but the present investigation is restricted to small radii because the shear-lift force is neglected.