A key element in the CDMA transmission is DS spreading. Spreading in a DS/SSMA system are provided in two categories-synchronization and data. For synchronization sequences, good auto-correlation and cross-correlation properties are required in order to guarantee fast acquistion with a minimum false alarm probability. On the other hand, the auto-correlation property may not be so important in data spreading since synchronization is obtained by synchronization spreading. In this paper we provide a set of synchronization sequences and a set of data sequences--each a set of binary N-tuples--that have the necessary correlation constraints.

We developed an eye-contact technique using a blazed half-transparent mirror (BHM), which is a micro-HM array arranged on the display surface, to make a compact eye-contact videophone. This paper describes a new BHM structure that eliminates ghosts and improves image quality. In the new BHM, the reflection and transmission areas are separated to exclude ghosts from appearing in the captured image. We evaluated the characteristics of the captured and displayed images. The results show that the contrast ratio of the captured image and the brightness of both captured and displayed images are much better than with the previous BHM.

The antenna factor measurement of the dipole antennas for electromagnetic interference (EMI) measurements is studied theoretically and experimentally. The 3-antenna method is applied to near-field. Near-field transmission characteristics between the transmitting and receiving dipole antennas is obtained by using the electromotive force (EMF) method, where sinusoidal current distributions are assumed. It is shown that the antenna factors can be measured from transmission values between two antennas and near-field correction factors at any height of each antenna.

Theoretical and experimental investigations of dipole antenna factors were carried out with special interest in their height patterns, since difference between them is a main cause of disagreement in EMI measurement results obtained with different antennas types. Antenna factors were expressed by matrix representation and their dependence on antenna dimensions and balun construction were numerically evaluated with the moment method. Those analyses revealed that antenna dimensions and balun characteristics have little effect on antenna factor height patterns. Slight influence was observed only at frequencies around 30MHz, when an antenna was placed less than 1.5m above a metal ground plane.

A light, thin and flexible applicator using a microstrip patch array for microwave heating is presented and tested in this work. The applicator is made of a flat silicone rubber bag, inside of which flows cooling water. EM coupling feeding is applied, which has no direct contact between the feed and the patch, to improve durability and reliability when it is repeatedly applied to the uneven surface of the heated portion of the human body. Simulations of SAR distribution are performed using the finite difference time domain (FD-TD) method. Simulated data are compared with the experimental ones using cubic and cylindrical phantom models with single and multielement patch applicators. Simulations of temperature distribution are also performed using the heat transfer equation. Simulated data are compared with the experimental ones using cubic and cylindrical phantom models. The simulated results agree well with the experimental ones. The results obtained here show that the multielement flexible microstrip patch applicator which operates at 430MHz can heat a relatively shallow and widespread area on the human body for hyperthermia treatments.

It has become very important to study the lightning surges that were induced in subscriber telecommunication equipment because of the increase of susceptible circuits to the over voltage. The test generator is desire to be developed evaluating the resistibility of equipments against lightning surges. This paper proposes a new lightning-test method for subscriber telecommunication equipment. The waveform of the test generator simulates that of the induced lightning surge voltage caused by a nearby return stroke. The output impedance of the surge generator is determined to match the common-mode impedance of telecommunication lines. The damaged condition of circuit parts and the trouble occurrence rate estimated by using this method agree well with actual observations.

A system for measuring the low frequency amplitude and phase noises was set-up, with employing a phase sensitive detector and phase-shifter. It is noted that both noises were partly correlated. The phase noise was explained by the transit time fluctuation due to the fluctuating diffusion coefficient. The amplitude noise reduction was demonstrated by applying the inverted output of the phase noise to the amplitude noise.

Recognition of hand drawn shapes is beneficial in drawing packages and automated sketch entry in hand-held computers. Although it is possible to store and retrieve drawings through the use of electronic ink, further manipulation of these drawings require recognition to be performed. In this paper, we propose a new approach to invariant geometric shape recognition which utilizes a fuzzy function to reduce noise and a neural network for classification. Instead of recognizing segments of a drawing and then performing syntactical analysis to match with a predefined shape, which is weak in terms of generalization and dealing with noise, we examine the shape as a whole. The main concept of the recognition method is derived from the fact that internal angles are very important in the perception of the shape. Our application's aim is to recognize and correctively redraw hand drawn ellipses, circles, rectangles, squares and triangles. The neural network learns the relationships between the internal angles of a shape and its classification, therefore only a few training samples which represent the class of the shape is sufficient. The results are very successful, such that the neural network correctly classified shapes which were not included in the training set.

This paper presents improvement of data error rate against burst noise by using both chip interleaving and hard limiter in direct sequence spread spectrum (DS/SS) communication systems. Chip interleaving, which is a unique method of DS/SS systems, is effective when burst noise power is small. However, when the burst noise power is large, date error rate is degraded. While, though hard limiter suppresses burst noise power, it gives little effectiveness when the burst noise length is long. Using chip interleaving and hard limiter together, as they work complementary, stable and considerable improvement of data error rate is achieved.

In this paper, a new off-line handwritten word recognition method based on the explicit modeling of character junctures is presented. A handwritten word is regarded as a sequence of characters and junctures of four types. Hence both characters and junctures are explicitly modeled. A handwriting system employing hidden Markov models as the main statistical framework has been developed based on this scheme. An interconnection network of character and ligature models is constructed to model words of indefinite length. This model can ideally describe any form of hamdwritten words including discretely spaced words, pure cursive words, and unconstrained words of mixed styles. Also presented are efficient encoding and decoding schemes suitable for this model. The system has shown encouraging performance with a standard USPS database.

Feasibility of 20 Gbit/s single channel transoceanic soliton transmission systems with a simple EDFA repeaters configuration has been studied. Both a simple and versatile soliton pulse generator and a polarization insensitive optical demultiplexer, which can provide a almost square shape optical gate with duration of full bit time period, have been proposed and demonstrated by using sinusoidally modulated electroabsorption modulators. The optical time-division multiplexing/demultiplexing scheme using the optical demultiplexer results in drastic improvement of bit error rate characteristics. We have experimentally confirmed that the use of alternating-amplitude solitons is an efficient way to mitigate not only soliton-soliton interaction but also Gordon-Haus timing jitter constraints in multi-ten Gbit/s soliton transmission. Timing jitter reduction using relatively wide band optical filter bas been investigated in 20 Gbit/s loop experiments and single-carrier, single-polarization 20 Gbit/s soliton data transmission over 11500 km with bit error rate of below 10-9 has been experimentally demonstrated, using the modulator-based soliton source, the optical demultiplexer, the alternation-amplitude solitons, and wide-band optical filters. Obtained 230 Tbit/skm transmission capacity shows the feasibility of 20 Gbit/s single channel soliton transoceanic systems using fully practical technologies.

Telecommunications management activities have mostly been supported by operators; however, machines are gradually playing more important roles in the management arena by utilizing computing technology. Additionally, management systems can now be networked by using standard interface specifications. The study of human and machine integration is thus essential for achieving the sophisticated management objectives of telecommunications. This paper proposes the principles for a telecommunications management integration network (TMIN), which integrates human and machine management networks, and proposes a source text description method for transferring management communication knowledge from human to machine. First, reference models are proposed for the management process and management communication. These models cover network management activities of both humans and machines. Second, the contents of the source text are clarified. Source text presents human management knowledge in a form suitable for machine-machine communication. Third, an efficient source text description method is proposed that reduces redundancy and proliferation. Finally, a means of harmonizing management information definitions with TMIN is suggested to facilitate human-machine cooperation.

Managed Objects (MOs) can be specified by the combination of a static information model and a dynamic process model. First, this paper presents a mapping of attributes from a process model diagram to an information model diagram. Then, it introduces a concept of topology into these two models and proposes a hypothesis about the relationship of topology in these two models. To explicitly explain the hypothesis, it can be stated that all attributes of incoming or outgoing data related to a process in a process model are mapped to an information model where these attributes are interconnected by an explicit relationship which corresponds to a specific meaning, such as physical containment or logical connection. From an intuitive perspective, it can be said that if two attributes have a close topological relationship in a process model, the mapped attributes also have a close topological relationship in an information model. This hypothesis provides clues for determining whether there is an error in an attribute either in the process model or in the information model. By examining the way attributes of incoming or outgoing data related to a process are mapped to an information model, we can detect whether there is an error with respect to the process. The error correction is performed with the assistance of probability analysis. The method of error detection and correction can be implemented in a computer aided tool. Then, error detection on the attribute level becomes automatic, and error correction on the attribute level becomes interactive through the computer aided tool. Finally, the validity of the hypothesis is confirmed by analyzing ITU-T Recommendation M.3100. The specification of the fabric object class defined in M.3 100 is transformed into these two models and the hypothesis is validated for the analysis of the mapping between these two models.

We describe an application of InGaAs/AlGaAs VCSELs to multiple wavelength light source for optical interconnection. A flip-chip bonding technique is used to integrate the VCSELs lasing at different wavelengths. The integrated VCSELs of different wavelengths are individually grown and processed, so that one can optimize the device characteristics and the wavelength separation or distribution for multiple wavelength interconnection systems. A 9-wavelength VCSEL array with a wavelength separation of 5 nm has been successfully fabricated.

Coding scheme is discussed for M-Choose-T communication in which at most T active users out of M potential users simultaneously transmit their messages over a common channel. The multiple-access channel considered in this paper is assumed to be a time-discrete noiseless adder channel without feedback with T binary inputs and one real-valued output, and is used on the assumption of perfect block and bit synchronization among users. In this paper a new class of uniquely decodable codes is proposed in order to realize error-free M-Choose-T communication over the adder channel described above. These codes are uniquely decodable in the sense that not only the set of active users can be specified but also their transmitted messages can be recovered uniquely as long as T or fewer users are active simultaneously. It is shown that these codes have a simple decoding algorithm and can achieve a very high sum rate arbitrarily close to unity if exactly T users are active.

We have fabricated a microchip of a neural circuit with pulse representation. The neuron output is a voltage pulse train. The synapse is a constant current source whose output is proportional to the duty ratio of neuron output. Membrane potential is charged by collection of synaptic currents through a RC circuit, providing an analog operation similar to the biological neural system. We use a 4-bit SRAM as the memory for synaptic weights. The expected I/O characteristics of the neurons and the synapses were measured experimentally. We have also demonstrated the capability of network operation with the use of synaptic weights, for solving the A/D conversion problem.

Let L{0,1}* be a language and let λL : {0,1}*{0,1} be the characteristic function of the language L, i.e., if x ∈ L, λL (x) = 1; otherwise,λL (x) = 0. In this paper, we consider an adaptive checker with a single program F (resp. noncommunicating multiple programs F1, F2,...) for λL that works even when an incorrect program F* (resp. incorrect noncommunicating multiple programs F*1,F*2,...) for λL adaptively behaves according to inputs previously provided to the program F* (resp. the programs F*1,F*2,...). We show that (1) for any language L, there exists an adaptive checker with a single program for λL iff L and respectively have competitive interactive proof systems; and (2) that for any language L, there exists an adaptive checker with noncommunicating multiple programs for λL iff L and respectively have function-restricted interactive proof systems. This implies that for any language L, adaptive chekers with noncommunicating multiple programs for λL are as powerful as static ones with a single program for λL.

In this study, after focussing on an energy (or intensity) scaled variable of acoustic systems, first, a new regression analysis method is theoretically proposed by introducing a multiplicative noise model suitable to the positively scaled stocastic system. Then, the effectiveness of the proposed method is confirmed experimentally by applying it to the actual acoustic data.

We have fabricated a new analog memory with a floating gate as a key component to store synaptic weights for integrated artificial neural networks. The new analog memory comprises a tunnel junction (poly-Si/poly-si oxide/poly-Si sandwich structure), a thin-film transistor, two capacitors, and a floating gate MOSFET. The diffusion of the charges injected through the tunnel junction is controlled by switching operation of the thin-film transistor, and we refer to the new analog memory as switched diffusion analog memory (SDAM). The obtained characteristics of SDAM are a fast switching speed and an improved linearity between the potential of the floating gate and the number of pulse inputs. SDAM can be used in a neural network in which write/erase and read operations are performed simultaneously.

This paper proposes a method for constructing an interface between an operations system and a workstation (OpS-WS interface) in a telecommunications management system based on TMN. To construct this interface, an appropriate communication protocol must be selected to perform management through efficient message exchange. The human machine interface provided by the WS should specify the managed objects. The interface also needs to be implemented so as to minimize the software revisions needed when the computer or its associated window system, or both, are changed. The proposed method addresses all these requirements. GUI components for realizing the HMI function are defined as Managed Objects as are communication network resources. Therefore, the communication protocol in TMN is defined as unique and it is possible to separate the HMI Interface from the OpS. CMIP is employed as the communication protocol to provide efficient message exchange. Software components that realize the human machine interface are selected so as to satisfy functional requirements specific to telecommunications management. The managed objects (MOs) and their relationships are investigated in order to represent these components appropriately. In the proposed method, the CMIP-based OpS-WS interface allows the OpS to take the manager role and the WS take the agent role. An implementation technique for MOs is also presented. The technique enables the software that implements MO behaviour to be coded easily. A prototype is built to confirm the correct operation of the proposed OpS-WS interface, and it is shown that CMIP requires fewer message exchanges to indicate alarms on the WS than other protocols. The proposed method is also advantageous because of its flexibility. That is, the WS software can be updated with little effort when the computer or its associated window system, or both, are changed.