In recent years, fractal processes have played important roles in various application fields. Since a 1/f process possesses the statistical self-similarity, it is considered sa a main part of fractal signal modeling. On the other hand, noise reduction is often needed in real-world signal processing. Hence, we propose an enhancement algorithm for 1/f signal disturbed by white noise. The algorithm is based on constrained minimization in a wavelet domain: the power of 1/f signal distortion in the wavelet domain is minimized under a constraint that the power of residual noise in the wavelet domain is smaller than a threshold level. We solve this constrained minimization problem using a Lagrangian equation. We also consider a setting method of the Lagrange multiplier in the proposed algorithm. In addition, we will confirm that the proposed algorithm with this Lagrange multiplier setting method obtains better enhancement results than the conventional algorithm through computer simulations.

An advanced intelligent network (IN) provides service management along with telecommunication services, and has a two-layer architecture, i.e., a transmission layer and an intelligent layer. An advanced IN's programmability is achieved by a service-independent platform of nodes in the intelligent layer, and service-dependent software called logic programs. In contrast to telecommunication services, models for service management have not yet been established. This paper presents both execution and specification models for service management. The execution model is composed of three hierarchies that apply to various kinds of management operation. The specification model has the capability to define the details of data items. The specification language for service management is also proposed. Simulation on dynamic SQL based DBMS solved that; (1) Logic programs for service management can be made small size on the model, and (2) To provide efficient database operation, programmability must be enhanced if service management includes table with variable number of field operation.

A new method is proposed for generating synchronizable test sequences which can be applied in the distributed test architecture for protocol conformance testing. The method consists of a duplex digraph technique and a rural Chinese postman tour algorithm to generate a minimum-length synchronizable test sequence using distinguishing sequences.

A neural network approach called the "Gradual Neural Network (GNN)" for the time slot assignment problem in the TDM multicast switching system is presented in this paper. The goal of this NP-complete problem is to find an assignment of packet transmission requests into a minimum number of time slots. A packet can be transmitted from one source to several destinations simultaneously by its replication. A time slot represents a switching configuration of the system with unit time for each packet transmission through an I/O line. The GNN consists of the binary neural network and the gradual expansion scheme. The binary neural network satisfies the constraints imposed on the system by solving the motion equation, whereas the gradual expansion scheme minimizes the number of required time slots by gradually expanding activated neurons. The performance is evaluated through simulations in practical size systems, where the GNN finds far better solutions than the best existing altorithm.

As enterprises use ATM networks for their private networks and as these private networks use public ATM networks for wide area communication, the need for the customers to be able to manage both private and public networks is increasing. Currently, some standardization work is being done towards providing this capability to customers. In this paper, we propose a new customer network management (CNM) system architecture for the management of both private and public ATM networks in a uniform way. The particular features of the proposed architecture lies in the efficient support of the complex hierarchical TMN manager-agent relationships at M3 and M4 interfaces, and the support of SNMP and CMIP integration. The TMN hierarchical many-to-many manager-agent relationships are realized by the utilization of a CORBA-based Shared Management Knowledge (SMK) system. We have implemented a prototype of ATM CNM system, and measured the performance for the demonstration of the suitability of the proposed architecture.

The interworking between high speed networks is receiving more attention recently. Among them, Frame Relay/Asynchronous Transfer Mode (FR/ATM) interworking is foreseen in the near future to provide seamless service across geographic areas. In the heterogeneous network interworking environment, an interworking function facility called the interworking unit (IWU) is generally interposed between these networks to perform the essential protocol conversion. As an intermediate network component, IWU will have great influence on network performance in terms of data latency. The performance issues of IWU are identified and addressed in this paper. These issues include frame processing schemes, frame shaping schemes, and cell processing schemes. The cell processing performance issues are further investigated via simulation experiments. Connectionless (CL) data service is also expected to be one of the most important applications for FR/ATM interworking. Some alternative methods for providing CL service over FR and ATM are described. We propose an enhanced protocol stack in the IWU to interoperate with the ATM network which uses the direct method to provide CL service. To proveide VPN service, we propose a feasible VPN communication structure based on the FR and ATM network interworking.

Calculation Nv(x) of complex order v numerically, we must calculate Df{JN+ε(x)}. When Df{JN+ε(x)} is calculated by the recurrence method, this letter will analyze the error of Df{JN+ε(x)}, and will determine the optimum number of recurrences.

As the number of different video compression algorithms in use and also the specific bit rates at which they are operated increase, there is a growing need for converters from one algorithm or bit rate to another. In general, this can only be accomplished by decoding and re-encoding. It has previously been assumed that the additional delays introduced by such decoding and re-encoding are additive and thereby become unacceptable for some interactive applications. This paper shows that it is possible to construct a transcoder such that the aggregate end-to-end delay is substantially less than the sum of the delays from the two encode and decode pairs. Two techniques are described. The first is more general while the second is simpler but is restricted to the case of reducing the bit rate and keeping the same compression algorithm. Results from simulations of the latter method are included.

Dynamic Term Rewriting Calculus is a new computation model proposed by the authors for the purpose of formal description and verification of algorithms treating Term Rewriting Systems. The computation of DTRC is basically term rewriting. The characteristic features of DTRC are dynamic change of rewriting rules during computation and hierarchical declaration of not only function symbols and variables but also rewriting rules. These features allow us to program metacomputation of TRSs in DTRC, that is , we can implement in DTRC in a natural way those algorithms which manipulate term rewriting systems as well as those procedures which verify such algorithms. In this paper, we give a formal description of DTRC. We then show some results on confluence property of DTRC.

This paper focuses on recovering from processor transient faults in pipelined multiprocessor systems. A pipelined machine may employ out of order execution and branch prediction techniques to increase performance, thus a precise computation state would not be available. We propose an efficient scheme to maintain the precise computation state in a pipelined machine. The goal of this paper is to implement checkpointing and rollback recovery utilizing the technique of precise interrupt in a pipelined system. Detailed analysis is included to demonstrate the effectiveness of this method.

This paper presents a discrete-time multiple short-time Fourier transform (MSTFT) suitable for a time-frequency analysis and synthesis of discrete-time nonstationary signals. An overcomplete set of multiple windows in used for a frame constitution in l2 (Z) so that higher quality signal analysis and perfect reconstruction of the signal are achieved. A design method for a prototype window is given where the window can satisfy regularity condition and have a flexible, good time and frequency characteristic under constraint of the uncertainty principle. A dual frame is constructed using the prototype windows in the framework of a frame operator method. Efficient implementation structures for the MSTFT and its inverse transform appropriate for real time numerical processing is presented. Simulation results are given to illustrate the effectiveness for design of the MSTFT. The performance advantages as a new signal analysis tool are demonstrated with an experimental signal.

We study state feedback control of discrete event systems described by the Golaszewski-Ramadge model. We derive a necessary and sufficient condition for the existence of a balanced state feedback controller under partial observations.

A two-dimensional receiver OEIC array having an address selector for highly parallel interprocessor networks has been realized. The receiver OEIC array consists of two-dimensionally arranged 1616 (256) optical receiver cells with switching transistors, address selectors (decoders), and a comparator. Each optical receiver comprises a pin PD and a transimpedance-type HBT amplifier. The HBT has an InP passivation structure to suppress the emitter-size effect, which results in the improvement of current gains, especially at low collector current densities. The receiver OEIC array was fabricated on a 3-inch diameter InP substrate with pin/HBT integration technology. Due to the function of address selection, only one cell is activated and the other cells are mute, so the receiver OEIC array shows low crosstalk and low power consumption characteristics. The array also shows a 266-Mb/s data transmission capability. This receiver OEIC array is a most complex InP-based OEIC ever reported. The realization of the two-dimensional receiver OEIC array promises the future interprocessor networks with highly parallel optical interconnections.

ATM networks are proposed by CCITT as the solution for the future B-ISDN. In ATM networks, the cells are transmitted between user and network without flow control, therefore, a policing mechanism (PM) is needed to check that the source traffic doesn't exceed the negotiated parameters. The sources supported by ATM networks have a bursty nature. The control of the mean cell rate of the bursty sources is intended to increase the network utilization. The conventional PMs can't efficiently monitor the mean cell rate of bursty sources, therefore new PMs are needed. In this letter, we propose a fuzzy policing mechanism (FPM). The performance evaluation via simulations shows that the FPM efficiently controls the mean cell rate of the packet voice source. The selectivity characteristics of the FPM approach the ideal characteristic required for a PM.

The supervisory control theory of discrete event dynamic systems was proposed in the framework of automata and formal languages. The concept of decentralized supervisory control was developed for the local supervisor Si whose concurrent operation results in the closed-loop language L (Si/G) equal to that of global supervisor, L (S/G). In this letter we extend this concept by considering the problem of optinal combination of decentralized with centralized control in case pure decentralized control happens to be inadequate. We introduce the concept of locally controllable complementary tuple and present an analytical framework for nonhomogeneous decentralized supervisory control systems.

In bandlimited QPSK and QAM transmission systems, phase jitter occurs in the output of a carrier recovery circuit that uses a fourth-power multiplier. To analyze the phase jitter, an exact expression was derived for the autocorrelation function and power spectral density for the case in which bandlimited Gaussian noise and a QPSK or QAM signal with random modulation and arbitrary waveform are simultaneously applied to the fourth-power multiplier. Using this expression, the rms phase jitter of the recovered carrier in root-cosine-rolloff transmission systems for QPSK, 16QAM, 64QAM and 256QAM was calculated. It was shown that the conventional theories for rectangular waveforms are special cases of our theory.

Outage probability evaluation for a new category of wireless access systems is discussed. Wireless access systems dealt with in this paper are links which connect a portable terminal to a base station through a line-of-sight path. It is also assumed that the terminal equipment is operated in a still atate during actual communications. This mobility restriction enables the wireless access to have a capacity as high as the Mbit-order with high quality performance. Multipath fading observed in such a system may have more moderate variations than Rayleigh distribution. This paper tentatively designates the above wireless access as relocatable systems, and attempts to analyze their error performance, approximating the fading characteristics with Gamma-distribution. Also dynamic relations between bit error rate (BER) and signal-to-noise ratio are calculated under Gamma-distribution fading. Based on the analyses prediction methods for outage probability of typical QPSK systems are given, and thus it is established to design the performance aspect of relocatable systems with different features from both fixed and mobile systems.

Firstly we show a usuful property of the fast algorithm for computing linear complexities of p-ary periodic sequences with period pn (p: a prime). Secondly the property is successfully applied to obtain the value distribution of the linear complexity for p-ary periodic sequences with period pn.

Approximate maximum likelihood (ML) detection implemented by a reduced state Viterbi algorithm (VA), called the reduced state Viterbi coherent detection (RSVCD) algorithm in this paper, is described for the reception of uncoded M-ary PSK (MPSK) signals transmitted over additive white Gaussian noise (AWGN) channels. An M-state trellis, each state representing one of M signal constellation points, is used. The RSVCD algorithm performs parallel channel estimation based on the per-survivor processing principle (PSPP). Simple decision feedback CD (DFCD) is deduced as a special case of RSVCD. Unified BER expressions are derived for RSVCD, DFCD, and approximate ML detection implemented as an ML-state Viterbi algorithm (referred to as VACD) [6] as well as ideal CD and differential detection (DD). Computer simulation results are also presented and compared with theoretical results.

Recently, a wavelength division multi/demultiplexing system has been viewed with keen interest because it is possible to increase the transmission capacity and system flexibility. An arrayed waveguide grating (AWG) type of Multi/demultiplexer which is one of the key components to realize such a system has been developed by using Planar Lightwave Circuits (PLCs). Newly designed optical circuits have been incorporated into the AWG to control the center wavelength and to expand the pass band width. The 3 dB pass band width is 1.4 times that of a conventional AWG. It is confirmed that the newly developed AWG has low polarization dependence, low temperature dependence and high reliability.