This paper presents a new timing-driven global routing method for standard cell layout. The proposed method can explicitly consider the timing constraint between two registers and minimize the channel density under the given timing constraint. In the proposed method, first, we determine the initial global routes. Next, we improve the global routes to satisfy the timing constraint between two registers as well as to minimize the channel density. Finally, for each cell row, the nets incident to terminals on the cell row are assigned to channels to minimize the channel density using 0-1 integer linear programming. We also show the experimental results of the proposed method implemented on an engineering workstation. Experimental results show that the proposed method is quite promising.

In forthcoming multimedia environments, continuous-media data, such as video and audio data, will be used by a variety of multimedia applications. Multimedia applications require efficient and flexible support from real-time operating systems. This is because the changes in system and network loads require dynamic management of real-time thread behavior. If threads are implemented at the user level, operations on threads can be processed at the user level, and the efficient management of threads becomes possible by avoiding kernel interventions. Thus, we can provide an effective platform for multimedia applications. The goal of our work is to realize high-performance user-level real-time threads which satisfy the above requirements of multimedia systems. In this paper we describe the design and implementation of a user-level real-time threads package, called RTC-Threads, which is being developed on the RT-Mach microkernel. The results of performance evaluations show that our user-level real-time threads outperform real-time kernel-provided threads, which are implemented in the microkernel, in terms of efficiency and accuracy.

A new type of guided-wave polarization splitter is proposed for the operation at optical frequencies. The basic structure of the device is a bifurcating waveguide fabricated in a uniaxial crystalline material such as LiNbO3. The splitting behavior of optical waves into two waves with mutually perpendicular directions of polarization by an optically anisotropic material is utilized in the branching section of the present polarization splitter. Once of the conspicuous features of the device is free of any electrical control via the electro-optic effects. Some numerical results obtained with the finite difference beam propagation method indicate that extinction ratios better than 20dB are possible of realization for both TE and TM modes.

The scattering problem of a plane wave by an axially slotted conducting elliptic cylinder in homogeneous medium is investigated. We present an accurate analysis using the modified point matching method, which can reduce the order of the simultaneous equations to be solved at least by a half under the condition of the same accuracy as compared with an usual point matching method. The accuracy of our results is checked by evaluating the relative errors. Numerical results are given for scattered field patterns by a conducting elliptic cylinder with a slot aperture of angle width 120 when the angle of incidence θinO.

This paper presents a novel clock routing method used in constructing an optimal clock tree for embedded array chips by determining the route so as to minimize both delay and skew. The proposed method features constructing a tree by optimal node-pair merging, predicting the upper side balancedtree structure, based on accurate global path or delay estimation. By this method, in the case of the chip with large macro cells, the delay estimation error has been within 10%.

In this paper, scattering problem of the grating coupler is analyzed by the mode-matching method in the sense of least squares for the gaussian light beam incidence. This coupler has a periodic groove structure of finite extent, which is formed on the surface of the core layer of the symmetric thin-film waveguide. In the present method, the approximate scattered fields of each region of the grating coupler are described by the superpositions of the plane waves with band-limited spectra, respectively. These approximate wave functions are determined by the minimization of the mean-square boundary residual. This method results in the simultaneous Fredholm type integral equations of the second kind for these spectra. The first and second order approximate solutions of the integral equations are derived analytically and the coupling efficiency and scattered fields are analyzed on the basis of those solutions. A qualitative and physical consideration for the scattering problem of the grating coupler is presented with the fundamental data derived from approximate solutions in this paper.

The electromagnetic force of evanescent field acting on dielectric slab is studied with the use of Maxwell stress tensor. The results show that dielectrics slab may receive always an attractive force when the incident wave is evanescent field while a pressure or an attractive force when the wave is propagating one. The magnitude of the attractive force by evanescent field is much larger than that of the propagating wave. And here some numerical examples are given.

In this paper, Chay's bursting pancreatic β-cell model is updated to include a role for [Ca2+]ER, the luminal calcium concentration in the endoplasmic reticulum (ER). The model contains a calcium current which is activated by voltage and inactivated by [Ca2+]i. It also contains a cationic nonselective current (INS) that is activated by depletion of luminal Ca2+ in the ER. In this model, [Ca2+]ER oscillates slowly, and this slow dynamic drives electrical bursting and the [Ca2+]i oscillations. This model is capable of providing answers to some puzzling phenomena,which the previous models could not (e. g., why do single pancreatic β-cells burst with a low frequency while the cells in an islet burst with a much higher frequency ?). Verification of the model prediction that [Ca2+]ER is a primary oscillator that drives electrical bursting and [Ca2+]i oscillations in pancreatic β-cells awaits experimental testing. Experiments using fluorescent dyes such as mag-fura-2-AM could provide relevant information.

44 matrix-based analysis of electromagnetic waves scattered by an infinite array of slots with polar-type anisotropic media are presented. In the analysis, the total fields are given as sum of the fields which exist even if the apertured plane are replaced by a ground plane and the fields scattered from the magnetic currents within the apertures. The scattered fields are expanded in terms of two-dimensional Floquet modes. Expression of each fields are obtained through eigenvalue problem for 44 coupled wave matrix. Unknown magnetic currents in the apertures are determined by applying Galerkin's method to the continuity condition about the magnetic fields in the apertures. Calculated results for isotropic cases are compared with other results for the complementary problem available in the literature using Babinet's principle. Further numerical calculations are performed in the case of gratings with polar-type anisotropic slab.

The problem of electromagnetic scattering by capacitive discontinuities located in rectangular waveguides, in particular when dealing with discontinuous conductors of finite thickness, is analyzed using the modified residue-calculus method, and form of the equation suitable for a numerical calculation is derived. The incident wave is taken to be the dominant mode, and reflection and transmission properties of an asymmetric capacitive iris are discussed. After the modal representation of the filed, the modal matching is apply to satisfy the boundary conditions at the discontinuity. And using the modified residue-calculus method, simultaneous infinite equations, which are concerned with the scattered mode coefficients, are derived. Then they are approximated at the thick diaphragm. The solutions obtained take on the form of an infinite product, and a numerical solution based on the method of successive approximations is presented as a technique for concretely determining the reflection coefficients. As confirmation, experiments are also carried out in the X-band and close agreement is shown between the calculated and experimental values.

This paper presents a three layer over-the-cell (OTC) routing algorithm for standard cells with nonuniform OTC routing capacities in standard cell design. Since the number of available routing tracks on the second metal layer of OTC varies column by column, the proposed OTC routing method can effectively utilize the OTC regions. The proposed router performs two types of OTC routing. For the OTC regions near the channel, it performs planar routing. For the OTC regions far from the channel, it performs H-V routing on the second and third layers. Combining planar and H-V routings, the router can utilize the OTC effectively, that could hardly be achieved by existing algorithms. We also formulate the problem of selecting planar routable nets on the third layer as the maximum weighted planar routable net selection problem with nonuniform routing capacity, and propose an optimal algorithm. Experimental results show that the proposed router produces small height layouts as compared to those produced by the routers based on the existing cell model with uniform OTC routing capacity.

BaSnO3 is proposed as a new insulating material with good surface coverage of the lower superconductor electrode for superconductor/insulator/superconductor (SIS) tunnel junctions made of high-Tc superconductor YBa2Cu3Ox (YBCO). This paper reports on investigation of the epitaxial nature of BaSnO3 on YBCO thin films and YBCO/BaSnO3 /YBCO trilayer formation that are grown in situ by reactive co-evaporation in oxygen radicals. Investigation was done by reflection high-energy electron diffraction (RHEED), atomic force microscopy (AFM), and X-ray diffraction (XRD). these observations confirm that (001)-oriented YBCO and (100)-oriented BaSnO3 thin films with atomically smooth surfaces grow epitaxially on each other. In addition, cross-sectional transmission electron microscopy (TEM) observation reveals that an approximately 4-nm-thick layer of BaSnO3 perfectly covers the lower YBCO thin film surface steps to a height of 1 to 2 unit cells of YBCO. The zero-resistance critical temperature Tc zero of both the upper and the lower YBCO thin films is higher than about 86 K.

Many numerical simulation problems of natural phenomena are formulated by large tridiagonal and block tridiagonal linear systems. In this paper, an efficient parallel algorithm to solve a tridiagonal linear system is proposed. The algorithm named bi-recurrence algorithm has an inherent parallelism which is suitable for parallel processing. Its time complexity is 8N - 4 for a tridiagonal linear system of order N. The complexity is little more than the Gaussian elimination algorithm. For parallel implementation with two processors, the time complexity is 4N - 1. Based on the bi-recurrence algorithm, a VLSI oriented tridiagonal solver is designed, which has an architecture of 1-D linear systolic array with three processing cells. The systolic tridiagonal solver completes finding the solution of a tridiagonal linear system in 3N + 6 units of time. A highly parallel systolic tridiagonal solver is also presented. The solver is characterized by highly parallel computability which originates in the divide-and-conquer strategy and high cost performance which originates in the systolic architecture. This solver completes finding the solution in 10(N/p) + 6p + 23 time units, where p is the number of partitions of the system.

Personal communication systems (PCS) have more signalling traffic than conventional fixed networks and require large-scale databases to manage users' profiles, which are sets of data items, such as the location the user is currently visiting and the user's authentication key, necessary for a PCS user to be provided with PCS services. This paper focuses on inter-network roaming in PCS environments. In designing a PCS supporting roaming service, it is essential to avoid increased signalling traffic and data searching time in the database. We first identify the appropriate domains for three routing schemes-Direction Routing, Redirection Routing, and Look-ahead Routing-from the viewpoints of the number of signals for inter-network roaming and roaming probability. We do this for two kinds of PCS database network architecture, Home Location Register (HLR) and Visitor Location Register (VLR), and show that Look-ahead Routing is the best scheme for the HLR network architecture (considering the number of signals for intra-network and inter-network database access) and that in the VLR network architecture, the decreasing of the roaming probability expands domains for which Redirection Routing is appropriate. We also propose a generic PCS data model that inter-network roaming interfaces can use to search effectively for a user's profile. The data model clarifies the contents of a set of data items which share certain characteristics, data items that the contents compose, and the relationships (data structures) between sets of data items. The model is based on the X. 500 series recommendations, which are applied for an Intelligent Network. We also propose a data structure between sets of data items using the directory information tree and show the ASN. 1 notations of the data model.

In this paper we propose a class of byte-error-correcting codes derived from algebraic curves which is a generalization on the Reed-Solomon codes, and present their fast parallel decoding algorithm. Our algorithm can correct up to (m + b -θ)/2b byte-errors for the byte length b, where m + b -θ + 1dG for the Goppa designed distance dG. This decoding algorithm can be parallelized. In this algorithm, for our code over the finite field GF (q), the total complexity for finding byte-error locations is O (bt(t + q - 1)) with time complexity O (t(t + q - 1)) and space complexity O(b), and the total complexity for finding error values is O (bt(b + q - 1)) with time complexity O (b(b + q - 1)) and space complexity O (t), where t(m + b -θ)/2b. Our byte-error-correcting algorithm is superior to the conventional fast decoding algorithm for randomerrors in regard to the number of correcting byte-errors in several cases.

In this paper, coded modulation techniques suitable for satellite broadcasting of digital high-definition TV are studied. An overview of current approaches to satellite broadcasting is presented. New constructions of coded modulation schemes for unequal error protection (UEP), based on both block and trellis codes, are introduced in this paper. The proposed schemes can achieve both better overall performance and enhanced graceful degradation of the received signal, in comparison with existing digital satellite broadcasting approaches.

Introducing a mathematical model of image noise, we formalize the problem of fitting a line to point data as statistical estimation. It is shown that the reliability of the fitted line can be evaluated quantitatively in the form of the covariance matrix of the parameters. We present a numerical scheme called renormalization for computing an optimal fit and at the same time evaluating its reliability. We also present a scheme for visualizing the reliability of the fit by means of the primary deviation pair and derive an analytical expression for the reliability of a line fitted to an edge segment by using an asymptotic approximation. Our method is illustrated by showing simulations and real-image examples.

In Perosonal communication systems (PCS), reduction control of call blocking rate on wireless-environments, especially in terminating-call set up, is one of the key technologies to design network architecture. This is because the error rate of transferred messages there is normally much higher than that in wired environments. Terminating-call reforwarding technologies, to forward twice terminating-call messages through paging channels depending on call states, would be essential under such conditions, and in the PCS network architecture there are two possible reforwarding schemes: network-assisted reforwarding (NAR) and cell-station-assisted reforwarding (CAR). We first propose a traffic model for evaluating the performance of terminating-call reforwarding from the viewpoint of reduction of the call blocking rate on PCS, and then we clarify the advocating domains for NAR and CAR. Finally, we present a case study using this evaluation model for the Personal Handy-phone System (PHS), which is a PCS in Japan. The results of this study confirm that NAR is more efficient than CAR.

Introducing a mathematical model of image noise, we formalize the problem of fitting a conic to point data as statistical estimation. It is shown that the reliability of the fitted conic can be evaluated quantitatively in the form of the covariance tensor. We present a numerical scheme called renormalization for computing an optimal fit and at the same time evaluating its reliability. We also present a scheme for visualizing the reliability of the fit by means of the primary deviation pair. Our method is illustrated by showing simulations and real-image examples.

Superconductive LSIs with Josephson junctions have features such as low power dissipation and high switching speed. In this paper, we review our developed 4-Kbit RAM with vortex transitional memory cells as an illustration of superconductive LSIs with Josephson junctions. We have developed a fabrication process technology for the 4-Kbit RAM. In the 4-Kbit RAM, 380ps access time and 9.8 mW power dissipation have been experimentally obtained. And also, we have estimated a suitable moat structure to reduce the influence of trapped magnetic structure. The 4-Kbit RAM has been successfully operated with a bit yield of 99.8%. Furthermore, we discuss GHz testing which is one of the most significant issues concerning superconductive digital LSIs.