This paper is concerned with two important planning problems for transport network planning; circuit routing problems and facility planning problems. We treated these optimization problems by taking into account survivability requirements. In the circuit routing problem tackled in this paper, therefore, optimization of circuit restoration plans, namely allocation of spare capacity for assumed failure scenarios is considered together with optimization of circuit routing in a no failure case. In the facility planning problems, failure scenarios of new facilities whose installation is yet to be determined are considered. In this paper, we present a formulation of these two optimization problems, and give 1) optimization algorithms based on the IA (Increment Assignment) method for routing problems and 2) optimization algorithms based on a combination of the GA (Genetic Algorithm) and the IA method for facility planning problems. The IA based routing algorithm can cope flexibly with various constraints on practical network operations and is applicable to large-scale complicated network models without causing a rapid increase in computation time. The GA based facility planning algorithm includes the IA based algorithm as a function for evaluating objective function values. Taking advantage of the important features of the IA based algorithm, we propose an acceleration technique for the GA based facility planning algorithm. In this paper, several numerical examples are provided and the effectiveness of the proposed algorithms is numerically evaluated.

This paper discusses the development of a design tool which supports a process for constructing PVC-based, ATM networks. Because of mathematical complexities, a heuristic approach has been adopted to find an optimal network configuration. Through a GUI, users define a physical network, and PVC networks which are logically constructed within the physical network. Based on the defined network configurations and user traffic demand, the tool evaluates performance measures. In response to the results of the evaluation, network designers can modify the network configuration to improve the performance. With the aid of this tool, they can repeat this interactive process until the estimated performance measures meet a desired quality. The tool has been applied to the design of several private ATM networks which will be constructed in the near future. The response time of this design tool is so fast that wait time can be negligible.

The Virtual Path (VP) concept is one of the versatile features of ATM/B-ISDN. Using the VP concept, a bundle of virtual circuits can be grouped together between any two switching nodes in the network. Further, the VP bandwidth and routing can be dynamic. Building on this idea, a dynamically reconfigurable, dynamic call routing wide area (backbone) broadband network concept is proposed. Specifically, this provides dynamism at two levels: at the VP level and at the connection level. For an incoming connection request, at most two logical virtual path connections (VPCs) are allowed between the origin and the destination; these logical VPCs are defined by setting virtual paths links (VPLs) which are, in turn, physically mapped to the transmission network. Based on the traffic pattern during the day, the bandwidth of such VPCs and their routing, as well as call routing, changes so that the maximum number of connection requests can be granted while maintaining acceptable quality of service (QoS) for various services. Within this framework, we present a mathematical model for network design (dimensioning) taking into account the variation of traffic during the day in a heterogeneous multi-service environment. We present computational results for various cost parameter values to show the effectiveness of such networks compared to static-VP based networks in terms of network cost.

The use of existing metallic local line facilities is being studied for the provision of high-speed digital transmission services. Local line characteristics have to be modeled in the form of the objective requirements that should be met by DSL for estimating the feasibility of the service provision in the actual network. This paper presents the results of a study that models the metallic media characteristics of NTT's local network. First, the line lenghts determined by the existing local line deployment rule and the cable types used in the networks are introduced. Second, the values of crosstalk characteristics, the most significant factors in limiting DSL range, are given by classifying essential line conditioning states of each cable. The values of crosstalk characteristics are newly computed by taking into account detailed cable pair-binding (cabling) structures, and the worst case values among all possible combinations of multiple inter-pair interfering-interfered relationships within a cable are given though a previous study approximated cable pair-binding structures. The crosstalk characteristics of NTT's and American local networks are also compared. A modified approximate equation of line propagation characteristics is also proposed for representative local lines, and its precision is verified by comparing simulation results to actual measurements in both frequency and time domains.

The emerging, ATM network will support permanent, semi-permanent and switched virtual channel connections (SVCC). A number of simulation studies have been carried out to study the performance of SVCCs using empirical data. The absence of an analytical model has prevented the study of SVCCs under known traffic distributions. In this paper, we develop a new delayed vacation model to facilitate the performance study of SVCCs with configurable inactivity timer in the ATM network interface card (NIC). Comparison with simulation results indicates that the proposed model is very accurate and can be effectively used to optimise the performance of SVCCs by selecting an appropriate inactivity timer.

Narrow-band ISDN services may experience nonstationary traffic conditions. Therefore, switch design should take account of these conditions. We propose new performance measures for switching systems and describe a traffic model, which is a mixture of stationary Poissonian traffic and momentarily focused traffic. On the basis of this model, performance measures are determined so as to satisfy grade of service requirements that are in effect during some short interval after the momentarily focused traffic enters the system. We also propose an overload control scheme that uses these new performance measures. Finally, we show practical and numerical examples for the performance measures and overload control scheme.

This paper presents a novel approach to a soft-output equalizer, which makes a symbol-by-symbol soft-decision based on a posteriori probabilities (APP's) criterion in the presence of intersymbol interference. The authors propose a soft-output Viterbi equalizer (SOVE) employing expanded memory length in a trellis of the Viterbi algorithm with small arithmetic complexity. The proposed equalizer gives suboptimum soft-decision closer to that of a equalizer with the maximum a posteriori probabilities (MAP) algorithm than the conventional SOVE.

In this paper, an efficient one-way point-to-multipoint communication protocol (PTMP) is proposed. The PTM protocol is helpful to distribute information to many workstations simultaneously and correctly. The PTM protocol is designed for network channels with low error possibility. The PTM protocol utilizes broadcast for data distributing. Re-transmission request for lost packet is returned to the server, and acknowledgment for correctly received packets is not returned to the server. We have applied the protocol to the network presentation system. The network presentation system is intended to display same graphical images to multiple workstations simultaneously on an X window system. This presentation system is able to provide services for at least forty X servers simultaneously, the capacity is limited to X server performance, except for pixmap drawing. For the case of pixmap drawing, the system capacity is limited to the network bandwidth. To solve network bandwidth problem, we combined PTM protocol with the network presentation system. With PTM protocol, system performance is improved and the use of network bandwidth is lowered.

The present paper describes a novel approach to interconnecting and assembling components of MEMS at room temperature. The main drawback of the conventional bonding methods is their rather high process temperatures. The new method, which is referred as the surface activated bonding (SAB), utilizes the phenomena of the adhesion between two atomically clean solid surfaces to enable the bonding at lower temperature or even at room temperature. In the bonding procedure, the surfaces to be bonded are merely brought into contact after sputter-cleaning by Ar fast atom in ultrahigh vacuum conditions. TEM observations of the bonded interfaces show that a direct bonding in atomic scale is achieved in the interface between the micro-components. Based on the concept of this new bonding technology, a micro-assembly system was developed. The micro-assembly system is operated by means of a virtual manipulation system in which 3D model of the micro-components are manipulated virtually in a computer graphics constructed in the world wide web (WWW) scheme. The micro-assembly system will provide a new design tool of three dimensional MEMS by combining the possibility of the flexible assembly and the intuitive operations.

Verification of timed bisimulation equivalence is generally difficult because of the state explosion caused by concrete time values. In this paper, we propose a verification method to verify timed bisimulation equivalence of two timed processes using a symbolic technique similar to [1]. We first propose a new model of timed processes, Alternating Timed Symbolic Labelled Transition System (A-TSLTS). In an A-TSLTS, each state has some parameter variables, whose values determine its behaviour. Each transition in an A-TSLTS has a quard predicate. The transition is executable if and only if its guard predicate is true underspecified parameter values. In the proposed method, we can obtain the weakest condition for a state-pair in a finite A-TSLTS, which the parameter values in the weakest condition must satisfy to make the state-pair be timed bisimulation equivalent.

The reconstruction of 3-D moving images from transmitted parameters describing position, attitude and shape variation of objects in a virtual 3-D space has been studied as an application of three dimensional (3-D) image communication. The shape information was obtained from a database that was built in advance. Since an appropriate database of 3-D object shapes needs to be developed, efficient storage of the shape data of the actual objects might become a key technology. This paper proposes an efficient entropy coding method of voxel map data obtained with shape measuring equipment. The proposed method converts the voxel map data into an octree and encodes their node information with conditional probability on the state of neighbor nodes sequentially, beginning with the upper hierarchy level. This method has the property of being able to extract information up to a given arbitrary hierarchy level because of its hierarchical characteristic. For implementation, two methods are proposed for reducing the large number of contexts, one uses 3-D isotropism, the other uses sample statistics. The experimental coding results using several sample data sets show that the proposed method can reduce the information volume by about 20% in comparison to the ordinary method using unconditional entropy. The binary voxel map of 512512512 can be represented by approximately 680 kbits.

Force curves obtained from an elastic contact theory are shown and compared with experimental results. In the elastic contact theory, a pin-on-disk contact is assumed and the following interaction are taken into consideration; (i) elastic deformation, (ii) the specific energy of adhesion in the area of the contact, which is expressed as the difference between the surface energies and the interface energy, (iii) the long-range interaction outside the area of contact, assuming the additivity of the Lennard-Jones type potential, and (iv) another elastic term for the measurement system such as the cantilever stiffness of an atomic force microscope (AFM). In the limit when the stiffness is infinite, the theory conforms to Muller-Yushchenko-Derjaguin (MYD) theory. In the limit when the surface-surface interaction is negligible, the theory conforms to the analytical theory by Takahashi-Mizuno-Onzawa. In the limit when the stiffness is infinite and the long-range interaction outside the area of contact is negligible, the theory conforms to Johnson-Kendall-Roberts (JKR) theory. All parameters and all equations are normalized and the normalized force curve is obtained as the functional of only two parameters; (1) the normalized stiffness of the measurement system, and (2) the normalized distance which is used in the expression of the Lennard-Jones potential. The force-displacement plots are converted into force-penetration plots.

The dispersion characteristics of two nonidentical coupled microstrip lines and N identical coupled microstrip lines are analyzed using the coupled-mode theory combined with Galerkin's moment method in spectral domain. In this approach, the solutions to the original coupled microstrips are approximated by a linear combination of eigenmode solutions associated with the isolated single microstrip, and the reciprocity relation is used to derive the coupled-mode equations. The coupling coefficients are given by the simple overlap integrals in spectral domain between the eigenmode fields and currents of the individual microstrips. It is shown that the numerical results are in very good agreement with those obtained by the direct Galerkin's moment method over a broad range of weak to moderately strong coupling.

A quantitative study is made on performance of neutron penumbral imaging with a toroidal-segment aperture, and it focused on isoplanaticity of aperture point spread function and effect of the non-isoplanaticity on the reconstructed images. The results show that the aperture point spread function is satisfactorily isoplanatic for a small field of view, while for a large field of view the point spread function is not satisfactorily isoplanatic resulting in some distortion in the reconstructed image and reduction of resolution.

Integrating the power supply and signal processing circuit into one chip is an important step towards achieving a system-on-chip. This paper reviews and looks at the current technologies and their trends for power supply components such as DC-DC converters, intelligent power LSIs, and thin-film magnetic devices for the system-on-chip. A device structure has been proposed for the system-on-chip that is based on a quasi-SOI technique, in which the buried oxide layer is partially removed from the SOI substrate. In this structure, the CMOS devices for the digital signal-processing circuit and the bipolar transistors are formed in a conventional SOI region, and the CMOS analog devices and high-voltage devices are formed in a quasi-SOI region.

This letter presents a realization of active current-mode resonator with complex coefficients using CCIIs. The resonator can be used for cascade or leapfrog configuration of high-order bandpass filters with complex coefficients. For realizing the resonators, only the grounded capacitors and the grounded resistors as passive elements are required, therfore the resonator is suitable for the integrated circuit realization. The letter shows that the response error of the proposed circuit caused by nonideality of active components is more easily compensated than that of voltage-mode counterpart. Experimental result is used for verifying the feasibility of the proposed resonator.

The majority of independent locomotion microrobots pack batteries as their energy source. However, because the energy that can be stored in a battery is proportional to its volume, the operating time becomes shorter as the robot becomes smaller. To solve this problem the energy must be supplied from outside by wireless transmission. We propose a microwave energy transmission system for microrobots in metal piping. Because microwave is rectified and converted in the form of electric energy in this system, we developed a receiving antenna for microrobots in piping and a microwave rectifying circuit to generate high voltage. These were loaded on a microrobot, tested to drive a locomotive mechanism, and the efficiency of the proposed system was confirmed.

We propose a modification of the perfect shuffle connectivity graph used in optical networks, which ensures the balance of the traffic load on the WDM channels. When applied to the simple but popular case of 8 nodes, connected through a shortest path routing algorithm, it allows to increase the aggregate capacity of more than 14%.

A joint estimator for carrier phase, symbol timing, and data sequence is proposed. This fully digital scheme is systematically derived from the maximum likelihood estimation (MLE) theory. The simulation and the analytical results demonstrate that the scheme is asymptotical to the optimum in AWGN channel.

Digital-switching noise coupled into sensitive analog circuits is a critical problem in large-scale integration of mixed analog and digital circuits. This paper describes noise coupling of this kind, especially, through the substrate in CMOS integrated circuits, and reviews recent technical solutions to this noise problem. Simplified models have been developed to simulate the substrate coupling rapidly and accurately. A method using a CMOS comparator was proposed for measuring the effects of substrate noise, and equivalent waveforms of actual substrate noise were obtained. A circuit tecnique, called active guard band filtering, that controls the noise source is a new approach to substrate noise decoupling. CAD methods for handling substrate-coupled switching noise are making design verification possible for practical mixed-signal LSIs.