A double-layer Associative Memory System (AMS) based on the Cerebella Model Articulation Controller (CMAC) (CMAC-AMS), owing to its advantages of simple structures, fast searching procedures and strong mapping capability between multidimensional input/output vectors, has been successfully used in such applications as real-time intelligent control, signal processing and pattern recognition. However, it is still suffering from its requirement for a large memory size and relatively low precision. Furthermore, the hash code used in its addressing mechanism for memory size reduction can cause a data-collision problem. In this paper, a new high-order Associative Memory System based on the Newton's forward interpolation formula (NFI-AMS) is proposed. The NFI-AMS is capable of implementing high-precision approximation to multivariable functions with arbitrarily given sampling data. A learning algorithm and a convergence theorem of the NFI-AMS are proposed. The network structure and the scheme of its learning algorithm reveal that the NFI-AMS has advantages over the conventional CMAC-type AMS in terms of high precision of learning, much less required memory size without the data-collision problem, and also has advantages over the multilayer Back Propagation (BP) neural networks in terms of much less computational effort for learning and fast convergence rate. Numerical simulations verify these advantages. The proposed NFI-AMS, therefore, has potential in many application areas as a new kind of associative memory system.

A simple and efficient adaptive mesh generation for the approximate scalar analysis of optical waveguides is proposed. Two types of local weight estimates which can take into account both a field amplitude and its variation on a problem domain are introduced. One is a difference between linear and quadratic element solutions and the other is a residual for the partial differential equation to be solved. To show the validity and usefulness of the present scheme, the guided-mode analysis of a rib waveguide and the beam propagation analysis of a tilted slab waveguide and a Y-branching rib waveguide are performed.

The productivity of developing software for switching systems and the effects of using advanced software development methods were evaluated and analyzed. Productivity was found to be improved by using automatic code generation, simulator debugging, a hierarchical object-oriented software structure, and software-development-support tools. The evaluation showed that the total productivity was improved by about 20%, compared with a case where these efforts were not introduced. It also showed each effect of these methods and tools by evaluating their manpower saving ratios. These results are expected to benefit the development of various types of communication-switching and multimedia service systems. Also, our development-support tools and methods are expected to be the basis for attaining higher software development productivity.

A decision-directed carrier phase recovery scheme for high-speed satellite communications is proposed. Since the estimation is performed in complex domain from the baseband signal, the scheme has fast acquisition performance, unlike the conventional PLL. This merit makes it applicable for various wireless systems such as wireless local area networks (LANs), wireless asynchronous transfer modes (ATMs) and local multipoint distribution systems (LMDSs) that need high-speed burst signal communications. Also, this scheme can be implemented easily because low pass filters (LPFs) are utilized in filtering the estimates in order to suppress the noise within the carrier recovery loop. Moreover it does not require any divider or voltage-controlled oscillator (VCO). The performance is analyzed through analytical methods and simulation.

The problem of electromagnetic scattering caused by inductive discontinuities locate in parallel-plate waveguides, in particular when dealing with discontinuous conductors of finite thickness, is analyzed using the modified residue-calculus method, the equations suitable for a numerical calculation are derived. The incident wave is taken to be the dominant mode, and the reflection and transmission properties of a symmetrical inductive iris are discussed.

A method for expanding the channels of data acquisition unit used in distributed microcomputer data measure & control systems and a technique to call assembly routines by C Language are introduced in the paper. The method may increase the number of data acquisition points ten to hundreds times. So it may raise the price performance ratio of all distributed data measure & control system greatly. And the programming method may optimize program performance.

Development of large-scale software is usually conducted through a project to unite a work force. In addition, no matter what kind of life cycle model is employed, a development plan is required for a software development project in order for the united work force to function effectively. For the project to be successful, it is also necessary to set management objectives based on this plan and confirm that they are achieved. This method is considered to be effective, but actually making a software development project and following the achievement of the management objectives at each step is not easy because predicting the necessary work amount and risks that the project involves is difficult in software development. Therefore, it is necessary to develop a system to support software project management so that the project manager can manage the entire project and the work load is reduced. This paper proposes a meta-model of work structure of software development projects for project management by using an object-oriented database with constraints as well as a framework for software project management systems based on this meta-model. Also proven, through an example of a system that analyzes repercussions on progress of a software development project, is that the meta-model and framework are effective in software project management.

For the improvement of software quality and productivity, the author aims at realizing a software development environment to develop software through utilizing the merits of group work. Since networking is necessary for collaborative software development, he has developed a software distributed development environment for collaborative software development. In this environment, discussions about software design are held through a communication network, and the contents of discussions are recorded as software design decisions and decision rationale. One feature of this environment is that the contents of discussions can be recorded in on-line real time and reused without reconstructing the information recorded through this environment. This paper clarifies the essential conditions for actualizing this environment and proposes an information structure model for recording the contents of discussions that actualizes the above-mentioned feature. The effectiveness of the proposed model is proved through an example of its application to software design discussions.

We introduce an ontology for transportation systems demand forecasting and its implementation into a decision support system (DSS) generator. The term ontology, as we use it here, means a collection of building blocks necessary and sufficient to construct a skeleton of a specific DSS, that is a task ontology. The ontology is specified in constraint logic, which also ensures a good support for modularity.

This paper discusses a method to evaluate mutual couplings of cavity-backed slot antennas using the FDTD technique. The antenna fed by the short-ended probe is considered, which is investigated as an element of the power transmission antenna, Spacetenna, for the solar power satellite SPS2000. It is found from the FDTD computation on E-plane two- and four-element array antennas that the size of the problem space should be larger for the evaluation of the mutual coupling than for the estimation of the input impedance. Since enlarging the size of the problem space requires a large amount of computer storage, it is not practical for computer simulations. In order to carry out accurate estimations of the mutual coupling with relatively small amount of computer memory, the problem space is extended only in the broadside of the array antenna and in the other directions there are ten cells between the antenna surface and the outer boundary. Computer simulations demonstrate that there are no differences between the results of the proposed problem space geometry and the problem space extended in each direction of the axis coordinate by the same number of cells. Furthermore comparisons of computed and experimental results demonstrate the effectiveness of the approach after discussing how large the size of the problem space is required to estimate the mutual coupling.

We propose a programming language, Flage, for building software systems which dynamically adapt to changing local situations. In our language, we construct applications by agents; concurrent mobile objects with the metalevel architecture. Metalevel programming facilities realize a self-control of an agent's actions and an autonomous adaptation to changes. We also introduce another kind of program element called field. A field represents a local situation around agents. For example, one field represents a virtual place to get local information in a network environment and another represents a virtual place where agents do cooperative works. If an agent enters a field, it gets programs and shared information in the field. By moving field to field, an agent can change its program composition by itself and it adapts to changing local situations. In this paper, we describe the language specification of Flage, the implementation of the platform for Flage programming and show some program examples.

In this paper, millimeter-wave radar cross section (RCS) characteristics for rough surface is investigated by means of an approximation method of the magnetic field integral equation and the feasibility of road condition sensing is discussed. The RCS measurement at 94 GHz is carried out in order to verify the numerical result, thereby the numerical results are in good agreement with the measured RCS. The dependence of RCS on the radar incidence angle and surface roughness is investigated where the cross-polarized RCS characteristic is also considered.

In recent years, several global network systems using non-stationary satellites have been proposed. Some of them are announced to start services within years. We also have several experimental systems with stratospheric aircrafts. In the future, the radio communication system using stratospheric aircrafts will be one of the promising media for personal communications. The question of how to establish the optimal communication under such circumstance seems to be still open. In this paper, performance evaluations of wireless communication systems using LEO satellites and stratospheric aircrafts are proposed. We will show some proper communication parameters to improve competence of mobile communication in the such systems as well.

This paper proposes the radio ATM entrance network with radio links connecting between access points and wired backbone ATM networks for wireless ATM access. In order to reduce the interference power among the radio entrance links, the Power and Modulation Level Controlled Radio method is newly proposed, the method controls not only modulation level but also the transmission power according to the ATM cell traffic intensity. Theoretical analysis shows that the proposed method can increase the carrier to noise plus interference power ratio and can reduce the average cell loss rate compared with the conventional Modulation Level Controlled Radio method in case that there is the interference power among the radio ATM entrance links.

This paper proposes a novel signal transmission scheme for helicopter satellite communications. The proposed scheme is based on time diversity, and combined with a novel algorithm to suppress an influence of carrier phase slip. In the proposed scheme, carrier phase slip is detected in cross correlation processing of the received signal, and is effectively suppressed. The proposed scheme thus makes it possible to employ coherent phase shift keying modulation to achieve bit error rate performance superior to that of differential phase shift keying modulation even in the low carrier-to-noise power ratio environment.

A novel zero-voltage-switched half-bridge converter is proposed. This converter achieves the zero-voltage switching while maintaining a constant frequency PWM control. Then the power conversion of high efficiency and low noise is realized at a higher switching frequency. In the experiment, a high efficiency of 83% is achieved for a low output voltage of 3.3 V, an output current of 30 A, and an input-voltage range of 200 to 400 V at the switching frequency of 400 kHz.

The importance of technology retargeting for hard IPs is getting increased. However, recent advances in process technologies make layout reuse too complicated to be done by conventional compactors. As an efficient approach, this paper proposes a flexible layout abstraction model and a new layout synthesis algorithm. The synthesis algorithm provides a concurrent procedure of detailed wiring, compaction, and transistor layout generation by using a scan line to get better layout results than conventional compactors. We have applied this method to the technology retargeting of actual cell layouts and have achieved quite good results comparable to hand-crafted designs.

The mapping from a global routing to a feasible detailed routing in a number of 2D array routing structures has been shown to be an NP-complete problem. These routing structures include the Xilinx style routing architecture, as well as architectures with significantly higher switching flexibility. In response to this complexity, a different class of FPGA routing structures called Greedy Routing Architectures (GRAs) have been proposed. On GRAs, optimally routing each switch box, in a specified order, leads to an optimal chip routing. Because routing each switch box takes polynomial time, the mapping problem on GRAs can be solved in polynomial time. In particular, an H-tree GRA with W2+2W switches per switch box (SpSB) and a 2D array GRA with 4W2+2W SpSB have been proposed. In this paper, we improve on these results by introducing an H-tree GRA with W2/2+2W SpSB and a 2D array GRA with 3.5W2+2W SpSB. These new GRAs have the same desirable mapping properties of the previously described GRAs, but use fewer switches.

Analysis of frequency-dependent lossy transmission lines is very important for designing the high-speed VLSI, MCM and PCB. The frequency-dependent parameters are always obtained as tabulated data. In this paper, a new curve fitting technique of the tabulated data for the moment matching technique in the interconnect analysis is presented. This method based on Chebyshev interpolation enhances the efficiency of the moment matching technique.

The datapath width of a core processor has a strong effect on cost, power consumption, and performance of an embedded system integrated with memories into a single-chip. However, it is difficult for designers to appropriately determine the datapath width for each application because of the limited reusability of software and the lack of compilation techniques. The purpose of this paper is to clarify supports required from software for the optimal datapath width determination. As a solution, an embedded programming language, called Valen-C, and a retargetable Valen-C compiler are proposed. In this paper, the syntax and semantics of Valen-C along with the mechanism of the Valen-C retargetable compiler and how to preserve the accuracy of computation of programs in relation to various datapath widths are also described. Experiments with practical applications show that the total cost of the system including a core processor, ROM, and RAM is drastically reduced with little performance loss by reducing the datapath width.