This paper compares three typical system-sharing configurations for FTTH networks that provide narrowband and video distribution services and proposes a remote node locating strategy for each configuration. Two new evaluation factors, required land space and service provisioning effort, are included in the calculation, in addition to facility cost and maintenance effort. By considering these factors together, the total network cost is calculated and the sensitivity to the number of remote nodes is evaluated. Finally, the most economical system-sharing configuration is identified on the basis of the evaluations for two typical service areas in Japan, for both present and future cost environments.

In this paper, chaos synchronization in coupled discrete-time dynamical systems is studied. Computer results display the interesting synchronization behaviors in the mutually coupled systems. As possible applications of chaos synchronization, parameter estimations and secure communications are proposed. Furthermore, a modified OGY method is given, which converts a chaotic motion into a periodic motion.

This paper describes two main technologies for achieving reliable real-time distributed communications systems. One is the technology to prevent the influence of a fault in an autonomous distributed system from spreading to the whole system (called autonomous distributed system control). The other is a software structure based on distributed processing, the object-oriented approach, and layering for better maintainability and expandability (called OO software structure). For the autonomous distributed system control, several inter-subsystem communication methods are proposed and evaluated. From the standpoints of the fault processing and processing load, frames should be sent through a data link over ATM connection and when a fault occurs the link should be switched over without loss of data. A pilot system achieved good reliability without an excessive number of dynamic steps. This autonomous control method will lead to a highly reliable communications system with large capacity. For the OO software structure, this paper gives experimental results from the implementation of a prototype system. Its distributed environment should lead to high reliability by extending the CHILL run-time routine (RTR). This software structure promises to provide service quickly, to reduce costs, and to make the development of each layer's software independent. A real-time OS, e.g., CTRON kernel combined with RTR can give real-time performance, high reliability and high productivity over the distributed system. The use of RTR can reduce the time for the call recovery process.

In this paper, we propose the architecture of BALANCE (Better Adaptive Load-balancing through Acquiring kNowledge of Characteristic of an Environment) in which users can submit their jobs without acquiring either a status of an environment or characteristics of jobs and servers even in a widely connected heterogeneous network. The architecture of BALANCE includes three types of information bases and two types of daemons. Information bases, namely job, resource, and environment information base, manage the knowledge of job characteristics, available resources for CPUs, and status of the environment, respectively, as a proxy for users. The dispatching daemon selects an adequate server for each job using knowledge stored in the information bases. A service daemon executes each job. On completing each job, a service daemon gets a statistic of the job and returns it to the dispatching daemon where the job came from so that the statistic will be available at the next dispatching time. BALANCE enables an environment (1) to balance the load, (2) to share software functions as well as hardware facilities, and (3) to learn a user's job characteristics. We have implemented a prototype with more than 50 heterogeneous UNIX workstations connected by different networks. Two simple experiments on this prototype are presented. These experiments show a load balancing scheme that takes the characteristics of each job into account.

We are developing GENESIS, a new seamless total environment for designing, developing, installing, and operating various types of telecommunication networks as extremely large distributed processing applications in the future network integrated by ATM. Similar uniform architectures for quick introduction and easy management of service or operation applications have been proposed, such as by TINA, but there has been insufficient study on how to operate and con figure those applications. This paper discusses the implementation model and execution environment in GENESIS from the viewpoint of flexible operation according to network conditions. The implementation model can describe detailed configurations under various conditions on design or operation, independently of the execution environment. To achieve the goals of GENESIS, our execution environment provides message handling functions and a transparent interface for controlling network resources independently of the configuration, and dynamic reconfiguration functions that are independent of the execution. This paper also reports the prototype system GENESIS-1. The GENESIS-1 message handling mechanism and the effect of the reconfiguration functions are described.

Fractal image coding using iterated transformations compresses image data by exploiting the self–similarity of an image. Its compression performance has already been discussed in [2] and several other papers. However the relation between the performance and the self–similarity remains unclear. In this paper, we evaluate fractal coding from the perspective of this relationship.

The concept of flexible system is long being used by many researchers, aiming to solve some particular problem of adaptation. The problem is viewed differently in different situations. In this paper, we first give a set of definitions and specifications to generalize this concept applicable to any system and in particular to communication networks. Through these definitions we will formalize, what are the conditions a system should satisfy to be called as a Flexible Communication System. The rest of the paper we formalize the concepts of flexible information network, and propose an agent oriented architecture that can realize it.

Telecommunication services are becoming more and more personalized, integrated, and refined. Advanced personal and mobile telecommunication services, intelligent networks, and network management operations require cooperative network-wide distributed processing on a very large scale. Telecommunication programs must support these services with great flexibility, efficiency, and reliability. This paper proposes a new call processing model that improves the availability and flexibility of telecommunication programs. It first points out requirements, outlines the distributed processing platform PLATINA, and discusses several approaches to the enhanced call processing model. Then it explains the call processing program structure, and gives illustrations of mobile and multi- party service control as typical examples. The Caller-Callee decomposition reduces the complexity of the call processing program and enhances the call model; the separation of call and bearer enhances service flexibility and integration; distributed object-oriented techniques meet software evolution requirements. A prototype program has been implemented and has proved the effectiveness of this approach.

In this paper we propose a formal linearization method which permits us to transform nonlinear systems into linear systems by means of the Chebyshev interpolation. Nonlinear systems are usually represented by nonlinear differential equations. We introduce a linearizing function that consists of a sequence of the Chebyshev polynomials. The nonlinear equations are approximated by the method of Chebyshev interpolation and linearized with respect to the linearizing function. The excellent characteristics of this method are as follows: high accuracy of the approximation, convenient design, simple operation, easy usage of computer, etc. The coefficients of the resulting linear system are obtained by recurrence formula. The paper also have error bounds of this linearization which show that the accuracy of the approximation by the linearization increases as the order of the Chebyshev polynomials increases. A nonlinear filter is synthesized as an application of this method. Numerical computer experiments show that the proposed method is able to linearize a given nonlinear system properly.

Numerical studies of reaction–diffusion systems which consist of chaotic oscillators are carried out. The Rössler oscillators are used, which are arranged two–dimensionally and coupled by diffusion. Pacemakers where the average periods of the oscillators are artificially changed are set to produce target patterns. It is found that target patterns emerge from pacemakers and grow up as if they were in a regular oscillatory medium. The wavelength of the pattern can be varied and controlled by changing the parameters (size and frequency) of the pacemaker. The behavior of the coupled system depends on the size of the system and the strength of the pacemaker. When the system size is large, the Poincar return maps show that the behavior of the coupled system is not simple and the orbit falls into a high–dimensional attractor, while for a small system the attractor is rather simple and a one–dimensional map is obtained. Moreover, for appropriate strength of pacemakers and for certain sizes of the systems the oscillations become periodic. It is also found that the largest and local Lyapunov exponents of the system are positive and these values are uniformly distributed over the pattern. The values of the exponents are smaller than that of the uncoupled Rössler oscillator; this is due to the fact that the diffusion reduces the exponents and modifies the form of the attractor. We conclude that the large scale patterns can stably exist in the chaotic medium.

Synchronization has been one of the problems in M–ary spread spectrum communication systems. In this letter, we propose the frame synchronization method using the Hadamard matrix and a frame synchronization method of PCM communication systems. Moreover, we analyze the probabilities of keeping synchronous state and frame renewal rates, and we evaluate the relationship between these probabilities and the number of stages of counters.

A novel optoelectronic mesoscopic neural device is proposed. This device operates in a neural manner, involving the electron interference and the laser threshold characteristics. The optical output is a 2–dimensional image, and can also be colored, if the light emitting elements are fabricated to form the picture elements in 3–colors, i.e. R, G, and B. The electron waveguiding in the proposed device is analyzed, on the basis of the analogy between the Schrödinger's equation and the Maxwell's wave equation. The nonlinear neural connection is achieved, as a result of the superposition an the interferences among electron waves transported through different waveguides. The sizes of the critical elements of this device are estimated to be within the reach of the present day technology. This device exceeds the conventional VLSI neurochips by many orders of magnitude, in the number of neurons per unit area, as well as in the speed of operation.

This paper proposes a methodology for fine evaluation of the uncertain behaviors of systems affected by any fluctuation of internal structures and internal parameters, by the use of a new concept on the fuzzy mapping. For a uniformly convex real Banach space X and Y, a fuzzy mapping G is introduced as the operator by which we can define a bounded closed compact fuzzy set G(x,y) for any (x,y)∈X×Y. An original system is represented by a completely continuous operator f defined on X, for instance, in a form xλ(f(x)) by a continuous operator λ: YX. The nondeterministic fluctuations induced into the original system are represented by a generalized form of the fuzzy mapping equation xGβ (x,f(x)) {ζX|µG(x,f(x))(ζ)β}, in order to give a fine evaluation of the solutions with respect to an arbitrarily–specified β–level. By establishing a useful fixed point theorem, the existence and evaluation problems of the "β–level-likely" solutions are discussed for this fuzzy mapping equaion. The theory developed here for the fluctuation problems is applied to the fine estimation of not only the uncertain behaviors of system–fluctuations but also the validity of system–models and -simulations with uncertain properties.

Along with the improvement of micro processors and local area networks, a distributed system becomes useful to realize a telecommunication system. It has potential advantage to achieve both high performance and high reliability. However, the design of a distributed system tends to be more complicated compared to a conventional centralized system. For the purpose of the standardization of distributed processing, ISO and ITU-T study the Open Distributed Processing (ODP) and are currently standardizing the Basic Reference Model of ODP (RM-ODP). To avoid dealing with the complexity of distributed systems, RM-ODP defines five viewpoints. The viewpoint approach of RM-ODP is proposed as a framework for the design of a distributed system. Although some previous works give the design methods of distributed systems based on the ODP viewpoint approach, the detailed design method has not been fully specified or all of the five viewpoints are not taken into account. In this paper, we describe a detailed design method for a distributed telecommunication system based on the ODP viewpoint approach. The method applies the five viewpoints to the three phases of design of a distributed system, that is, requirement analysis, functional design and detailed design phase. It clarifies what specifications for the target system should be made from the individual viewpoints and how the specifications are related each other. It also takes account of the platform which provides the distribution support, and gives the design method for both the platform and the application specific functions on the platform. The design method is examined by applying it to the design of a distributed MHS system supporting X.400 series protocols. In this example, the remote procedure call based on the client-server model is selected as the base of the platform. The result shows that our method is useful to simplify the complexity of the design for a distributed telecommunication system.

ISO and ITU-T have developed the standard concept of the Telecommunications Management Network (TMN). This standard does not, however, specify interface implementation. The user requires an Application Programming Interface (API) that bridges user application and the TMN concept to construct a TMN-based application. This paper proposes an object oriented API (OOAPI) that is suitable for TMN-based operations system implementation. OOAPI is one interface of the Common Management Information Service Element (CMISE), and uses the Common Management Information Protocol (CMIP). OOAPI is composed of two C++ programming language constructs: Data Object and Interface object "M_User". The Data Object makes it easier for the user to access management information. The M_User provides a connection-less CMISE interface because the OOAPI handles CMIP association automatically. The M_User also provides MO location-transparency by using the OSI Directory Service. This paper compares the existing MO location-transparency schemes with the OOAPI method, and clarifies the advantages of OOAPI. This paper also indicates results from OOAPI trials, and confirms that OOAPI has sufficient performance to implement highly effective TMN operations system.

A new optical path cross-connect system architecture (OPXC) based on delivery and coupling matrix switches is described. This OPXC provides the maximum compatibility for a wavelength path (WP) network and a virtual wavelength path (VWP) network. In other words, the proposed architecture easily evolves from WP-OPXC to VWP-OPXC. This salient feature can not been achieved with conventional OPXCs. Another attractive feature of this OPXC is its high modularity for OPXC capacity expansion.

We predict that chemical waves can propagate as a guided mode in a reaction-diffusion system that consists of two regions with different wave speeds. In comparison with electromagnetic waveguides, unique features of the guided chemical waves can be seen in their dispersion characteristics. Conditions for supporting lowest-loss guided waves are discussed.

State space explosion is a serious problem in analyzing discrete event systems that allow concurrent occurring of events. A new method is proposed for generating reduced state spaces of systems. This method is an improvement of Valmari's stubborn set method. The generated state space preserves liveness, livelocks, and terminal states of the ordinary state space. Petri nets are used as a model of systems, and a method is shown for generating a reduced state space from a given Petri net.

High-speed pulse propagation, up to several hundred Mbps or higher, will play an important role in telecommunication systems for B-ISDN. High-performance packaging, especially high-speed, high-throughput interconnection, is strongly required. For advanced telecommunication systems, giga-bit signal transmission has been developed at the multi-chip module level, and 300 to 600 Mbps signal transmission has been reached at the printed circuit board level. Electrical inter-cabinet interconnections of 150 to 300 Mbps have been achieved for up to several tens of meters. High-speed, high-throughput connectors are the key to achieving high-performance telecommunication packaging systems. Two technologies are extremely important. One is for high-density, high-pin-count connectors, and the other is for high-speed signal transmission connectors. The requirements for the connectors needed for advanced high-performance telecommunication systems are described. Several high-density, high-bandwidth connectors developed for high-performance packaging system are introduced.

This paper proposes an adaptive modulation/TDMA scheme to achieve high capacity personal multi-media communication systems. TDMA is employed to cope with various bit rate for multi-media services. The modulation scheme is selected from 1/4-rate QPSK, 1/2-rate QPSK, QPSK, 16QAM and 64QAM according to the received C/IC (power ratio of the desired signal to the co-channel interference) and the delay spread. The spectral efficiency is evaluated by using the simulated bit error rate (BER) performance as well as the cumulative distribution of the C/IC with parameters of cell configurations. The results show that the spectral efficiency of the proposed scheme is 3.5 times higher than that of the conventional QPSK systems at the outage probability of 10%, and the effect is more remarkable at lower outage probability. The results also show that the proposed adaptive modulation is effective in improving delay spread immunity.