This paper analyzed the connection points of Main Distribution Frames (MDF), which are installed between outside plants and inside plants (service nodes). This paper also proposes a connecting system for forthcoming FITL (Fiber In The Loop) networks. NTT has developed the Subscriber Line Cross-Connecting Module (LXM) for the FITL network and will continue to introduce LXMs and deploy optic subscriber networks in big cities throughout Japan.

Because 60 GHz frequency band has been allotted for the research and development purpose of millimeter wave systems in Japan, various circuit components and systems have been fabricated by using printed transmission lines. The NRD guide (nonradiative dielectric waveguide) is another candidate as a transmission medium for millimeter wave integrated circuit applications since its performance has been shown to be excellent in this frequency band. This paper is concerned with the development of a 60 GHz digital transceiver for millimeter wave LAN use based on NRD guide technologies. The trans-ceiver consists of frequency stabilized Gunn oscillator, circulator, PIN diode modulator, balanced mixer, directional coupler and transmitting and receiving pyramidal horn antennas. The notable advantages of the circuit components are the high reliability of the Gunn oscillator, the wide bandwidth of the circulator, and the high frequency operation of the PIN diode modulator beyond 100 Mbps. Interference between transmitted and received signals, which must be caused by coupling between transmitting and receiving antennas, is eliminated by simple techniques such as introducing filters in the base band and IF circuits. By using NRD guide digital transceivers, both-way data transmission between two computers can be achieved simultaneously and a 60 GHz wireless LAN system has been developed successfully.

A requirement specification acquisition method combined with hypothesis-based reasoning and model reasoning is proposed for obtaining service specifications from the ambiguous and/or incomplete requirement specifications of communications services. Errors at an early stage of software development cost more to debug than those at a later stage. Specification acquisition is the most upstream development process. Nevertheless, the system support for specification acquisition is delayed compared with other development phases.' Users do not always have precise requirements. It is therefore inevitable that user requirements contain ambiguities, insufficiencies and even contradictions. Considering this, it is indispensable to support a specification completion method that derives service specifications from such problem requirements. This paper proposes a combined method to obtain consistent and complete specifications from such problem requirements. Communications service specifications can be described by specifying terminal behaviors which can be recognized from outside the communications system(s). Such specifications are described by a rule-based language. Requirement specifications usually have components that are ambiguous, incomplete, or even contradictory. They appear as rule description and/or missing rules. From such requirements, service specifications are obtained by using hypothesis-based reasoning on input requirements and existing service specifications. When existing specifications cannot be used to obtain complementary specifications, a communications service model is used to propose new rules. The proposed methods are implemented as a part of a communications software development system. The system enables non-experts in communications systems to define their own service specifications.

The Time-Slicing paradigm is a newly developed method for the training of neural networks for speech recognition. The neural net is trained to spot the syllables in a continuous stream of speech. It generates a transcription of the utterance, be it a word, a phrase, etc. Combined with a simple error recovery method the desired units (words or phrases) can be retrieved. This paradigm uses a recurrent neural network trained in a modular fashion with natural connectionist glue. It processes the input signal sequentially regardless of the input's length and immediately extracts the syllables spotted in the speech stream. As an example, this character string is then compared to a set of possible words, picking out the five closest candidates. In this paper we describe the time-slicing paradigm and the training of the recurrent neural network together with details about the training samples. It also introduces the concept of natural connectionist glue and the recurrent neural network's architecture used for this purpose. Additionally we explain the errors found in the output and the process to reduce them and recover the correct words. The recognition rates of the network and the recovery rates for the words are also shown. The presented examples and recognition rates demonstrate the potential of the time-slicing method for continuous speech recognition.

This paper reports on a high-speed silicon bipolar transistor with an fT and fMAX of over 40 GHz, we call it the Advanced Boro-silicated-glass Self-Aligned (A-BSA) transistor. In basic BSA technology, a CVD-BSG film is used not only as a diffusion source to form the intrinsic base and the link base regions but also as a sidewall spacer between the emitter and the base polysilicon electrodes. An A-BSA transistor offers three advancements to this technology: (1) a graded collector profile underneath the intrinsic base region to suppress the Kirk effect; (2) an optimized design of the link base region to prevent the frade-off effect between fT and base resistance; and (3) a newly developed buried emitter electrode structure, consisting of an N++-polysilicon layer, a platinum silicide layer, and a CVD tungsten plug, to prevent the emitter plug effect. Furthermore, our transistor uses a BPSG filled trench isolation to reduce parasitic capacitance and improve circuit performance. In this paper, we describe device design, process technology and characterization of the A-BSA transistor, with it we have performed several application ICs, operating at 10Gb/s and above. The A-BSA transistor achieved an fT of 41 GHz and an fMAX of 44 GHz under optimized conditions.

An embedded cache memory for low power RISC microprocessors is described. An automatic-power-save architecture (APSA) enables the cache memory to operate with high speed at high frequencies, and with low power dissipation at low frequencies. A pulsed word technique (PWT) and an isolated bit line technique (IBLT) reduce the power dissipation of the cache memory effectively. Using these three techniques, the power dissipation of the cache memory is reduced to almost 60% of the conventional cache memory at 60 MHz and to 20% at a clock frequency of 10 MHz. An 8 KByte test chip using 0.5 µm CMOS technology was fabricated, and it achieves 80 MHz operation at a supply voltage of 3.1 V, and 8 mW operation at a supply voltage of 2.5 V at 10 MHz.

This paper discusses our newly developed technology for making GaAs/InGaAs/GaAs Tetrahedral-Shaped Recess (TSR) quantum dots. The heterostructures were grown by low-pressure MOVPE in tetrahedral-shaped recesses created on a (111) B oriented GaAs substrate using anisotropic chemical etching. We examined these structures by using cathodoluminescence (CL) measurements, and observed lower energy emissions from the bottoms of, and higher energy emissions from the walls of the TSRs. This suggests carrier confinement at the bottoms with the lowest potential energy. We carried out microanlaysis of the structures by using TEM and EDX, and found an In-rich region that had grown vertically from the bottom of the TSR with a (111)B-like bond configuration. We also measured a smaller diamagnetic shift of the lower energy photoluminecscence (PL) peak in the structure. Based on these results, we have concluded that the quantum dots are formed at the bottoms of TSRs, mainly because of the dependence of InAs composition on the local crystalline structure in this system. We also studied the lateral distribution and vertical alignment of TSR quantum dots by CL and PL measurements respectively. The advantages of TSR quantum dot technology can be summarized as follows: (i) better control in dot positioning in the lateral direction, (ii) realization of dot sizes exceeding limitations posed by lithography, (iii) high uniformity of dot size, and (iv) vertical alignment of quantum dots.

A new prediction method for the effective address is presented. This method works with the buffer named the address prediction buffer, and allows the data cache to be accessed speculatively. As a consequence of the trend toward increasing clock frequency, the internal cache is no longer able to fill the speed gap between the processor and the external memory, and the data cache latency degrades the processor performance. In order to hide this latency, the prediction method is proposed. By this method, the load address is predicted, and the data is fetched earlier than the memory access stage. In the case that the prediction is correct, the latency is hidden. Even if the prediction is incorrect, the performance is not degraded by any miss penalties. We have found that the prediction accuracy is 81.9% on average, and thus the performance is improved by 6.6% on average and a maximum of 12.1% for the integer programs.

This paper concerns a Petri-net-based model for describing reactive and concurrent systems. Although many high-level Petri nets have been proposed, they are insufficiently practical to describe reactive and concurrent systems in the detail modeling, design and implementation phases. They are mainly intended to describe concurrent systems in the rough modeling phase and lack in several important features (e.g., concurrent tasks, task communication/synchronization, I/O interface, task scheduling) which the most actual implementations of reactive and concurrent systems have. Therefore it is impossible to simulate and analyze the systems accurately without explicitly modeling these features. On the other hand, programming languages based on Petri nets are deeply dependent on their execution environments and not sophisticated as modeling and specification languages. This paper proposes MENDEL net which is a high-level Petri net extended by incorporating concurrent tasks, task communication/synchronization, I/O interface, and task scheduling in a sophisticated manner. MENDEL nets are a wide-spectrum modeling language, that is, they are suitable for not only modeling but also designing and implementing reactive and concurrent systems.

A type of Lienard's equation +µf(x)+x=0, where f(x) is not an even function of x, is studied by Le Corbeiller as a model of various biological oscillations, such as breathing, and called two-stroke oscillators. A distinctive feature of this type of oscillators is that the parameter µ has the upper limit µ0 for the oscillator to have some stable limit cycle. This paper gives a numerical method for calculating this upper limit µ0.

Time-domain characteristics of the signal of an open-loop fiber optic gyroscope were analyzed. The waveform moments of the gyroscope signal were dependent upon the rotation-induced Sagnac phase, just as the signal frequency spectra are. The peak positions of the time signal also varied with the supplied rotation, and the Sagnac phase could be read out, with optimum sensitivity, from the intervals between peaks. To demonstrate the time-domain measurement technique, the gyroscope signal was transferred to lower frequencies and the signal period was lengthened. This equivalent-time scheme lowered the operational speed requirement on the signal processing electronics and improved measurement resolution.

We present a topological framework of stepwise specification for concurrent systems in this paper. Some of description techniques can make topologies on the system space. Such topologies corresponds to abstract levels of those description techniques. Using a family of such description techniques, one can specify systems stepwisely. This framework allows to bridge various DTs and modularizing, so that global properties and module properties of systems become to be related to each other. Within this framework, we show derivation of a LOTOS cpecification from temporal logic formulae. An extended version of LOTOS with respect to concurrency is used in this paper. A semantics including concurrency is introduced to do this in this method. The method presented in this paper is applied to mobile telecommunication.

This paper describes a circuit analysis technique that includes all circuit elements used in transistor Colpitts quartz crystal oscillators. This technique is applied to a quartz crystal oscillator that has a tank circuit for selecting the oscillation frequency. The results obtained with this technique are compared with SPICE simulation results. Good agreement in the results clearly shows the validity of our technique.

The aim of this study is to measure and quantify muscle fatigue of low back, caused by sitting on the vehicle seat for a long period of time. The authors proposed a new objective muscle fatigue index based on Principle Component Analysis utilizing the measured muscle viscoelasticity and EMG. The new index suggests an adequate correlation with the subjective fatigue.

The direct measurement of sidewall roughness on a ridge-type GaAs waveguide was performed using an atomic force microscope (AFM) combined with a scanning electron microscope (SEM). The ridge sidewall of a GaAs waveguide formed by wet-etching and the ridge sidewall formed after regrowth of a 2.45-µm GaAs/AlGaAs epitaxial layer on the same waveguide were observed using introducing the technique for sample slanting. The observed power spectral density was used to determine the scattering loss caused by the sidewall roughness. It was found that the ridge-type GaAs waveguide for light wave transmission had a scattering loss of 0.029 dB/cm in the as-etched ridge state and a scattering loss of 0.17 dB/cm after regrowing the cover GaAs/AlGaAs epitaxial layer. A leaky GaAs/AlGaAs waveguide for polariton-quantum-wave trans-mission had a scattering loss of 1.3l0-5 dB/cm, which means that the scattering loss is negligible. Furthermore, it was found that a periodical surface fluctuation (spatial frequency 2.2 µm-1) along the waveguide appeared after the regrowth of the epitaxial layer. Thus, this method is useful for direct observation of sidewall roughness and can be used to quantitatively determine the sidewall scattering loss.

We studied the application of precursor solutions that can be fired into oxides to form a protective layer for AC-type Plasma Display Panel (AC-PDP). Our study of alkoxide and metallic soap as MgO precursors revealed that the crystallinity of MgO films depends on the starting substance. Since the electric discharge characteristics of a panel and the lamination effect of the protective layer depend on precursors, it was confirmed that binders having higher crystallinity provide better characteristics. Our study revealed that a compound-oxide film has high crystallinity. The application of a Ba0.6Sr0.4Gd2O4 formation solution to a binder and the application of a Sr0.6Mg0.4Gd2O4 formation solution to a protective layer both are seemed promising We also found that a double-layer film, made by forming a protective layer of fine MgO powder and a Ba0.6Sr0.4Gd2O4 binder, on top of a protective layer made of fine MgO powder and a MgO binder, provides a luminous efficiency 5.3 times higher than that of sputtered MgO film which is one of candidates for the large panel, and the conventional electron beam evaporation is not suitable for the large panel. We further found that a triple-layer protective film made by forming a thin film of Sr0.6Mg0.4Gd2O4 provides low voltages of 1 V in firing voltage (Vf) and 35 V in sustaining voltage (Vs) compared to the double-layer film and provides a luminous efficiency 5.5 times higher than that of sputtered MgO film. A life test revealed the triple-layer film in particular providing a useful life of more than 10,000 hours. From these findings, we concluded that the compound-oxides which is composed of alkaline-earth-metal and rare-earth-element could be applied effectively to a protective layer for AC-PDP.

This paper presents the device technology for monolithic integration of InP-based resonant tunneling diodes (RTDs) and high electron mobility transistors (HEMTs). The potential of this technology for applications in quantum functional devices and circuits is demonstrated in two integration schemes in which RTDs and FETs are integrated either in Parallel or in series. Based on the parallel integration scheme, we demonstrate an integrated device which exhibits negative differential resistance and modulated peak current. This integrated device forms the foundation of a new category of functional circuits featuring clocked supply voltage. Based on the series integration scheme, resonant-tunneling high electron mobility transistors (RTHEMTs) with novel current-voltage characteristics and useful circuit applications are demonstrated. The high-frequency characteristics of RTHEMTs are also reported.

This paper is concerned with a point-oriented finite volume time domain (FVTD) method in the Cartesian coordinate system and its application to the analysis of electro-magnetic wave propagation in a bended waveguide as well as radiation from and receiving by a horn antenna with a flange of arbitrary angle. The perfectly matched layer (PML) is used for the absorbing boundary conditions (ABC's). The boundary conditions for a perfect conductor not well suited to the Cartesian coordinate system are also proposed. According to this algorithm, the boundary conditions are satisfied in an average fashion at the conductor surface without changing the computational scheme. In this sense, numerical computations based on the present method are simple but flexible. Numerical results show good convergence.

Synchronization and chaos of the oscillator circuit that is composed of two Duffing-Rayleigh oscillators coupled by resistor are investigated. The characteristic feature of this system is that the cubic nonlinear restoring force of each oscillator. The restoring force causes the Neimark-Sacker bifurcation with various synchronizations in the parameter plane. We clarify the bifurcation structure related with this nonlinear phenomenon, and study the chaotic state and its bifurcation process. Especially, we deals with the case that the symmetrical property is broken by changing system parameters.

A method is presented for reconstructing the surface profile of a two dimensional rough surface boundary from the scattered far field data. The proposed inversion algorithm is based on the Kirchhoff approximation and in order to determine the surface profile, the numerical results illustrating the method are presented.