Kiyotaka YAMAMURA Shin'ichi OISHI Kazuo HORIUCHI
Algorithms for computing channel capacity have been proposed by many researchers. Recently, one of the authors proposed an efficient algorithm using Newton's method. Since this algorithm has local quadratic convergence, it is advantageous when we want to obtain a numerical solution with high accuracy. In this letter, it is shown that this algorithm can be extended to the algorithm for computing the constrained capacity, i.e., the capacity of discrete memoryless channels with linear constraints. The global convergence of the extended algorithm is proved, and its effectiveness is verified by numerical examples.
This paper presents a method of calculating an interval including a bifurcation point. Turning points, simple bifurcation points, symmetry breaking bifurcation points and hysteresis points are calculated with guaranteed accuracy by the extended systems for them and by the Krawczyk-based interval validation method. Taking several examples, the results of validation are also presented.
Mitsunori MAKINO Masahide KASHIWAGI Shin'ichi OISHI Kazuo HORIUCHI
A priori estimation is presented for a computational complexity of the homotopy method applying to a certain class of strongly monotone nonlinear equations. In the present papers, a condition is presented for a certain class of uniquely solvable equations, under which an upper bound of a computational complexity of the Newton type homotopy method can be a priori estimated. In this paper, a condition is considered in a case of linear homotopy equations including the Newton type homotopy equations. In the first place, the homotopy algorithm based on the simplified Newton method is introduced. Then by using Urabe type theorem, which gives a sufficient condition guaranteeing the convergence of the simplified Newton method, a condition is presented under which an upper bound of a computational complexity of the algorithm can be a priori estimated, when it is applied to a certain class of strongly monotone nonlinear equations. The presented condition is demonstrated by numerical experiments.
Nobuyo KASUGA Katsuhito ITOH Shin'ichi OISHI Tomomasa NAGASHIMA
This study was conducted to examine the relationship between technostress - techno-centered tendency- and antisocial behavior on computers. Questionnaire data of computer operators were analyzed by multivariate-analysis. The results of the analysis indicated that high techno-centered tendency has a strong relationship with antisocial behavior on computers. Among the component factors of techno-centered tendency, absorption in operating computers was proven to have the strongest association with antisocial behavior on computers.
Mitsunori MAKINO Shin'ichi OISHI Masahide KASHIWAGI Kazuo HORIUCHI
A priori estimation is presented for a computational complexity of the homotopy method applying to a certain class of uniquely solvable nonlinear equations. In the first place, the reason is explained why a computational complexity of the homotopy method can not be a priori estimated in general. In this paper, the homotopy algorithm is considered in which a numerical path following algorithm is executed based on the simplified Newton method. Then by introducing Urabe's theorem, which gives a sufficient condition guaranteeing the convergence of the simplified Newton method, it is shown that a computational complexity of the algorithm can be a priori estimated, when it is applied to a certain class of uniquely solvable nonlinear equation. In this paper, two types of path following algorithms are considered, one with a numerical error estimation in the domain of a nonlinear operator and another with one in the range of the operator.
Mitsunori MAKINO Shin'ichi OISHI Masahide KASHIWAGI Kazuo HORIUCHI
In this paper, in the first place, a slightly version upped Urabe type theorem of convergence criterion is presented for the modified Newton method. Then, based on this theorem, a posteriori stopping criterion is presented for a class of numerical methods of calculating solutions including the simplicial approximate homotopy method for nonlinear equations. By this criterion it is estimated whether an approximate solution satisfies the conditions of the Urabe theorem or not. Finally, it is shown that under a certain mild condition a class of simplicial approximate homotopy methods such as Merrill's method generate an approximate solution which satisfies our stopping criterion in restarting finite steps.
This is the first to three expository articles, which aim to survey the chaos theory from an engineering point of view. This paper, in the first place, presents a brief introduction to chaos. Then, it is pointed out that the study of chaos from an engineering point of view is a challenging area in engineering science.
A new concept of "an imperfect singular solution" is defined as an approximate solution which becomes a singular solution by adding a suitable small perturbation to the original equations. A numerical method is presented for proving the existence of imperfect singular solutions of nonlinear equations with guaranteed accuracy. A few numerical examples are also presented for illustration.
Hisa–Aki TANAKA Toshiya MATSUDA Shin'ichi OISHI Kazuo HORIUCHI
The analytic structure of the governing equation for a 2nd order Phase–Locked Loops (PLL) is studied in the complex time plane. By a local reduction of the PLL equation to the Ricatti equation, the PLL equation is analytically shown to have singularities which form a fractal structure in the complex time plane. Such a fractal structure of complex time singularities is known to be characteristic for nonintegrable, especially chaotic systems. On the other hand, a direct numerical detection of the complex time singularities is performed to verify the fractal structure. The numerical results show the reality of complex time singularities and the fractal structure of singularities on a curve.
Hisa–Aki TANAKA Shin'ichi OISHI Kazuo HORIUCHI
This letter presents the results of an analysis concerning the global, dynamical structure of a second order phase–locked loop (PLL) in the presence of the continuous wave (CW) interference. The invariant manifolds of the PLL equation are focused and analyzed as to how they are extended from the hyperbolic periodic orbits. Using the Melnikov integral which evaluates the distance between the stable manifolds and the unstable manifolds, the transversal intersection of these manifolds is proven to occur under some conditions on the power of the interference and the angular frequency difference between the signal and the interference. Numerical computations were performed to confirm the transversal intersection of the system–generated invariant manifolds for a practical set of parameters.
Mitsunori MAKINO Shin'ichi OISHI Masahide KASHIWAGI Kazuo HORIUCHI
A type of infinite dimensional homotopy method is considered for numerically calculating a solution curve of a nonlinear functional equation being a Fredholm operator with index 1 and an A-proper operator. In this method, a property of so-called A-proper homotopy plays an important role.
Takao SOMA Shin'ichi OISHI Yuchi KANZAWA Kazuo HORIUCHI
This paper is concerned with the validation of simple turning points of two-point boundary value problems of nonlinear ordinary differential equations. Usually it is hard to validate approximate solutions of turning points numerically because of it's singularity. In this paper, it is pointed out that applying the infinite dimensional Krawcyzk-based interval validation method to enlarged system, the existence of simple turning points can be verified. Taking an example, the result of validation is also presented.
Kiyotaka YAMAMURA Shin'ichi OISHI Kazuo HORIUCHI
An iterative decomposition method with mesh refinement strategies is presented for the numerical solution of nonlinear two-point boundary value problems. It is shown that this method is more efficient than the traditional finite difference methods and shooting methods.
Shin'ichi OISHI Joos VANDEWALLE
One parameter family of solutions of the second Painlevé equation, which describes long time asymptotic behavior of waves in certain soliton transmission lines, are constructed through its bilinear form. It is then shown that the derived solutions have the Painlevé characteristic, i.e., they have no movable critical points.
A function R(L), named a rate-risk function, is introduced in the field of statistical decision theory. It specifies the minimal permissible rate R at which information about under-lying uncertainties must be conveyed to the decision maker in order to achieve the prescribed value L of the Bayes risk. Fundamental properties are also clarified for the rate-risk function.
The purpose of the present paper is to review a state of the art of nonlinear analysis with the self-validating numerical method. The self-validating numerics based method provides a tool for performing computer assisted proofs of nonlinear problems by taking the effect of rounding errors in numerical computations rigorously into account. First, Kantorovich's approach of a posteriori error estimation method is surveyed, which is based on his convergence theorem of Newton's method. Then, Urabe's approach for computer assisted existence proofs is likewise discussed. Based on his convergence theorem of the simplified Newton method, he treated practical nonlinear differential equations such as the Van der Pol equation ahd the Duffing equation, and proved the existence of their periodic and quasi-periodic solutions by the self-validating numerics. An approach of the author for generalization and abstraction of Urabe's method are also discribed to more general funcional equations. Furthermore, methods for rigorous estimation of rounding errors are surveyed. Interval analytic methods are discussed. Then an approach of the author which uses rational arithmetic is reviewed. Finally, approaches for computer assisted proofs of nonlinear problems are surveyed, which are based on the self-validating numerics.
Akira INOUE Masahide KASHIWAGI Shin'ichi OISHI Mitsunori MAKINO
In this paper, we are concerned with a problem of obtaining an approximate solution of a finite-dimensional nonlinear equation with guaranteed accuracy. Assuming that an approximate solution of a nonlinear equation is already calculated by a certain numerical method, we present computable conditions to validate whether there exists an exact solution in a neighborhood of this approximate solution or not. In order to check such conditions by computers, we present a method using rational arithmetic. In this method, both the effects of the truncation errors and the rounding errors of numerical computation are taken into consideration. Moreover, based on rational arithmetic we propose a new modified Newton interation to obtain an improved approximate solution with desired accuracy.
Recent progress in the theory of nonlinear waves" has clarified that various nonlinear dispersive soliton transmission equations can be transformed into certain types of bilinear equations. In this paper, a general form of bilinear soliton transmission equations which have a form of simultaneous equations for two dependent variables is presented. Then, a method is presented for constructing their generalized soliton solutions, which are solutions expressing solitons in a background o ripples. As a result, it turns out that if these bilinear soliton transmission equations have N-soliton solutions, they also have the generalized soliton solutions. Moreover, taking the modified Korteweg-de Vries equation as typical example of the soliton transmission equations which are treated in this paper, it is also shown that its initial value problem can be solved using its generalized soliton solution. Since the results for the modified Korteweg-de Vries equation can be easily extended to all soliton transmission equations which can be transformed into a certain type of coupled bilinear equations and whose N-soliton solutions can be written by determinants, it also turns out that transmission characteristics of a wide class of nonlinear dispersive transmission equations reducible to coupled bilinear equations can be clarified by making use of their generalized soliton solutions. A simple application of these results to a design problem of soliton transmission lines is also noted.