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163
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Introduction
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November 2006 - present
Publications
Publications (35)
This study conducted a survey to implement educational applications that can share information even in environments where access points cannot be used. In particular, we investigated whether Bluetooth (widely used for many years) or Wi-Fi Direct (developed recently) is more suitable when creating educational applications using an ad hoc network. To...
This study conducted a survey to implement educational applications that can share information even in environments where access points cannot be used. In particular, we investigated whether Bluetooth (widely used for many years) or Wi-Fi Direct (developed recently) is more suitable when creating educational applications using an ad hoc network. To...
In this paper, we propose an efficient search method for unstructured P2P networks. The method is based on the existing method called expanding ring in which the search area is gradually enlarged. In expanding ring, a large number of queries are forwarded unnecessarily because the same query is forwarded to the same node multiple times. We mitigate...
In this paper, we present a method to compose conformal mapping functions of arbitrary given simply connected domains which are bounded by the smooth boundary curves of finite length onto the unit disk as the standard domain. The Riemann mapping theorem tells that such domains are conformally equivalent and the mapping functions are uniquely determ...
In this paper, we propose a method that extends the lifetime of wireless sensor networks by using multiple mobile sink nodes. The proposed method determines the positions of multiple sink nodes based on remaining battery levels of sensor nodes. When a sink node is moved, the new position of the sink node is determined considering the distance to ot...
We present a numerical method for the conformal mapping of unbounded multiply connected domains exterior to closed Jordan curves onto the general spiral slit domain, which is a natural extension of the circular and radial slit domains.
The aim of this study is to propose an efficient broadcasting method considering node density and to conduct a comparative evaluation with existing methods. In our proposed method, broadcasting is carried out efficiently using positional information attached to messages at the time of broadcasting and not by periodically exchanging positional infor...
We propose a numerical method for the conformal mapping of unbounded multiply connected domains exterior to closed Jordan curves C
1, . . . ,C
n
onto a canonical linear slit domain, which is the entire plane with linear slits S
1, . . . , S
n
of angles θ
1, . . . , θ
n
arbitrarily assigned to the real axis, respectively. If θ
1 = · · · = θ
n
= θ th...
It is possible to recover the original data from a certain amount of encoded data by using rateless codes, which are utilized for multicast streaming. In this paper, we propose an effective replication technique using rateless codes for unstructured P2P networks. More specifically, we propose a method to spread and find chunks generated from files...
Conformal mappings are familiar in science and engineering. Recently, the problem of multiply connected domains has attracted special interest. We here present a unified scheme for numerical conformal mappings of unbounded, multiply connected domains onto the parallel, circular and radial slit domains under two different conditions. These are canon...
Seamless availability on applying to the problems of various types of simply and multiply connected domains is one of the key features of Amano's method of numerical conformal mappings. We studied the application of the method for a doubly connected rectangular domain with a slit and obtain an approximation of the conformal mapping function which m...
We propose a numerical method for conformally mapping unbounded multiply connected domains onto a canonical domain with a mixture of circular and radial slits. It expresses an analytic function by a linear combination of complex logarithmic functions based on the charge simulation method, and gives a simple form of approximate mapping function with...
We recently presented a method of numerical conformal mapping of multiply-connected domains onto some canonical slit domains, where we approximated a pair of harmonic functions by a linear combination of complex logarithmic functions. We here present a method of numerical conformal mapping onto the parallel slit domain subject to a different condit...
The transformational group structure theory predicts ordinal relations of similarity of pattern pairs and goodness of patterns by the concept of transformational group structures. The validity of the prediction should be confirmed by a statistical test, which needs a multiple comparison of many classes. We applied the paired t-test and Tukey's HSD...
Usually, on computation of conformal mappings, different methods are used to obtain the mapping functions of two directions between a problem domain and a canonical domain.Amano proposed a method based on the numerical conformal mappings by the charge simulation method, and it offers the both mapping functions of simply connected problem domains an...
We present here a simple method of numerical conformal mappings from bounded multiply connected domains onto the bounded canonical slit domains of Nehari, i.e., a disk with concentric circular slits, and an annulus with concentric circular slits. In this method, we express the mapping functions in terms of a pair of conjugate harmonic functions and...
We present here a charge simulation method for problems of two-dimensional flows past obstacles in a two-dimensional periodic array. Our problem is mathematically a boundary value problem of the Stokes equation with periodic boundary conditions, to which it is difficult to give a good approximation by the ordinary charge simulation method. We propo...
In this paper, we propose a method of numerical conformal mappings from a domain with a curved slit onto the canonical slit domains. Our method is based on Amano's method, which uses the charge simulation method as a rapid solver for potential problems. Due to the potential solver, his method gives high accuracy in many cases. The basic idea of the...
We present here a fundamental solution method for two-dimensional viscous flow problems with obstacles in a two-dimensional periodic array. Our problem is mathematically a boundary value problem of the Stokes equations with periodic boundary conditions, to which it is difficult to give a good approximation by the ordinary fundamental solution metho...
We show that the linear system appearing in the invariant scheme of the charge simulation method is uniquely solvable when the scheme is applied to a two-dimensional Dirichlet problem for a disk, for an ellipse, and for an annulus with properly chosen charge points and collocation ones, which are extensions of the previous results due to Katsurada-...
We propose a method of numerical conformal mapping of periodic structure domains onto periodic parallel slit domains. In the method presented here, the mapping problem is reduced to a Dirichlet one for a pair of conjugate harmonic functions with a periodic boundary condition. We modify the charge simulation method for solving periodic boundary valu...
We propose a method of numerical conformai mapping of periodic structure domains onto periodic parallel slit domains. In the
method presented here, the mapping problem is reduced to a Dirichlet one for a pair of conjugate harmonic functions with a
periodic boundary condition. We modify the charge simulation method for solving periodic boundary valu...
We are concerned with the experiment on numerical conformal mappings. A potentially theoretical scheme in the fundamental solutions method, different from the conventional one, has been recently proposed for numerical conformal mappings of unbounded multiply connected domains. The scheme is based on the asymptotic theorem on extremal weighted polyn...
Recently, we proposed an integrated method for the problem of numerical conformal mappings of the unbounded multiply-connected domains onto the canonical slit domains of Nehari(l952). The problem is important in potential flow analysis. Our method which uses the charge simulation method offers not only highly accurate mapping functions, but also th...
We are concerned here with the numerical conformal mapping of bounded Jordan domains onto the unit disk, which is a basic problem of conformal mapping. We reduce the mapping problem to a Dirichlet problem of the Laplace equation with a pair of conjugate harmonic functions, to which the charge simulation method is applied and the conjugate harmonic...
A potentially theoretical scheme in the fundamental solutions
method, different from the conventional one, is proposed for
numerical conformal mappings of unbounded multiply connected
domains. The scheme is introduced from an algorithm on numerical
Dirichlet problem, based on the asymptotic theorem on extremal
weighted polynomials. The scheme intro...
Conformal mappings are familiar in science and engineering. But exact mapping functions are not known except for special domains. Particularly confomal mappings of a domain exterior to closed Jordan curves onto parallel, circular and radial slit domains are well known as a method of two-dimensional potential flow analysis. But no systematic method...
A simple method was recently proposed for numerical conformal mappings of a domain exterior to closed Jordan curves onto parallel, circular and radial slit domains. They are important in problems of two-dimensional potential flows around obstacles with vortexes, point-sources and sinks together with a uniform flow. We present an integrated scheme o...
We recently proposed a method for numerical conformal mappings of multiply connected open domains onto parallel, circular, and radial slit domains. These three types of standard domains are important in two-dimensional potential flow analysis. Our method uses the charge simulation method as the potential problem solver. The charge simulation method...
The numerical schemes for computing the approximations have been recently proposed for interior and exterior conformal mappings by Inoue (1997). The theoretical base and the mathematical properties of the schemes are studied in this paper. The base depends on theorems in Henrici (1986) introduced from Symm's integral equations. The mathematical pro...