We are developing multimodal man-machine interfaces through which users can communicate by integrating speech, gaze, facial expressions, and gestures such as nodding and finger pointing. Such multimodal interfaces are expected to provide more flexible, natural and productive communications between humans and computers. To achieve this goal, we have taken the approach of modeling human behavior in the context of ordinary face-to-face conversations. As the first step, we have implemented a system which utilizes video and audio recording equipment to capture verbal and nonverbal information in interpersonal communications. Using this system, we have collected data from a task-oriented conversation between a guest (subject) and a receptionist at company reception desk, and quantitatively analyzed this data with respect to multi-modalities which would be functional in fluid interactions. This paper presents detailed analyses of the data collected: (1) head nodding and eye-contact are related to the beginning and end of speaking turns, acting to supplement speech information; (2) listener responses occur after an average of 0.35 sec. from the receptionist's utterance of a keyword, and turn-taking for tag-questions occurs after an average of 0.44 sec.; and (3) there is a rhythmical coordination between speakers and listeners.

Electromagnetic radiation patterns of planar 915MHz Dual Concentric Conductor (DCC) antennas were investigated with theoretical finite difference time domain (FDTD) analyses and experimental measurements of power deposition in a homogeneous lossy dielectric load. Power deposition (SAR) patterns were characterized by scanning an electric field sensor in front of the radiating aperture 1 cm deep in liquid "muscle tissue" phantom. Results showed close agreement between the theoretical simulations and measured SAR patterns for a 3.5cm square aperture. Additional SAR measurements demonstrated the ability to vary aperture size from 3.5-6cm with minimal change in shape of the power deposition pattern. Both analyses indicated that effective power deposition (50% SARmax) extends to the periphery of the square apertures. These data support the conclusion that the DCC aperture constitutes an improved radiator to be used as the functional building block of larger array applicators which are required for adjustable heating of large superficial tissue regions in the treatment of cancer.

This paper describes that the dielectric characteristics of a catheter around the interstitial antenna have an effect on the wavelength for current, and this effect results in the variation of the SAR (Specific Absorption Rate) distribution around the antenna. A theoretical study of SAR distribution ground a coaxial-slot antenna is performed. Analytical technique used is the moment method. Result and discussion on the effect of material and thickness of the catheter are presented. The wavelength for the current shortens with increasing dielectric constant or decreasing thickness of the catheter. Due to this variation of the wavelength for current, the SAR distributions take various shapes.

Analysis of the specific absorption rate (SAR) of a realistic head model generated with a 1.5-tesla MRI antenna is described. It is found that the SAR of the eyeball is strongly affected by the position of the feeding point, whereas the sensitivity of the antenna is virtually independent of the feeding point.

In this paper, we propose a learning fuzzy network (LFN) which can be used to implement most of fuzzy logic functions and is much available for hardware implementations. A learning algorithm largely borrowed from back propagation algorithm is introduced and used to train the LFN systems for several typical fuzzy logic problems. We also demonstrate the availability of the LFN hardware implementations by realizing them with CMOS current-mode circuits and the capability of the LFN systems by testing them on a benchmark problem in intelligent control-the inverted pendulum system. Simulations show that a learning fuzzy network can be realized with the proposed LFN system, learning algorithm, and hardware implementations.

A multi-layer perceptron (MLP) acting directly in the time-domain is applied as a speech signal enhancer, and the performance examined in the context of three common classes of degradation, namely low bit-rate CELP degradation is non-linear system degradation, additive noise, and convolution by a linear system. The investigation focuses on two topics: (i) the influence of non-linearities within the network and (ii) network topology, comparing single and multiple output structures. The objective is to examine how these characteristics influence network performance and whether this depends on the class of degradation. Experimental results show the importance of matching the enhancer to the class of degradation. In the case of the CELP coder the standard MLP with its inherently non-linear characteristics is shown to be consistently better than any equivalent linear structure (up to 3.2 dB compared with 1.6 dB SNR improvement). In contrast, when the degradation is from additive noise, a linear enhancer is always, superior.

With a view toward the improvement of life-saving rate, the advancement of emergency radio system was attempted. The telemetry technique was introduced to the mobile communication from a running ambulance. A system was newly developed which enables us to transmit the information of an emergency patient from an ambulance to an emergency room of a hospital. This system can transmit an audio signal, physiological signals such as an ECG and a blood oxygen level, as well as a color image. In the experiment, the feasibility of this technique was verified. In the test of its practical usefulness, the following points were evaluated using a mobile telephone line and an emergency radio link. With the regular condition of the communication link, the stability of signal transmission was reasonably well. The fidelity of the transmitted signal was satisfactory for the use of an emergency medicine.

A partially ferrites and dielectric loaded water filled waveguide applicator is presented which can be used for microwave heating of tissues. The applicator can change its heating pattern by changing the external DC magnetic field applied to the ferrites. The electromagnetic (EM) field distribution inside the applicator is obtained theoretically and the simulated EM field inside the applicator is checked experimentally using 430MHz. Furthermore, on the basis of the EM field distribution inside the applicator, simulations of SAR distribution inside lossy homogeneous human tissue as muscle are performed using finite difference time domain (FD-TD) method. Simulated data of Specific Absorption Rate (SAR) distribution is compared with the experimental ones. Simulations of temperature distribution are also performed using heat transfer equation. Simulated data of temperature elevation distribution is compared with the experimental ones. The simulated results agree well with the experimental ones and it is confirmed that the heating pattern can be changed by external DC magnetic field applied to the applicator. The results obtained here show that the partially ferrites and dielectric loaded water filled waveguide applicator which operates at 430 MHz can change its heating pattern without changing its setup and can heat local target on the human body for hyperthermia treatment.

In this paper, we present an analysis of a high-speed slotted ring with a single packet buffer at each station. Assuming that distances between stations affect the network performance only through the sum of themselves (this will be called the "lumpability assumption"), we introduce a model system called the lumped model in which stations are aggregated at a single point on the ring with their relative positions preserved. At the instant when each slot visits the aggregated point of the lumped model, we build a Markov chain by recording the system state of buffers and slots. From the steady state probabilities of the Markov chain, we obtain the mean waiting time and the blocking probability of each station. It will be shown analytically and by simulation that the analysis based on the lumped model yields accurate results for various network conditions.

This paper proposes two algorithms for defining a routing domain in multiclass-of-service networks. One an off-line-based method, whose objective is to optimize dynamic routing performance by using precise knowledge on the traffic levels. The algorithm of the proposed method takes into account the random nature of the traffic flow, which is not considered in the network flow approach. The proposed method inherits the conceptual simplicity of the network flow approach and remains applicable to large and complex networks. In simulation experiments, the proposed off-line-based method performs better than the method based on the network flow approach, but has a similar the computation time requirement. The other method proposed here is an on-line-based method for application to B-ISDNs, where precise traffic data is not expected to be available. In this method, the routing domain is defined adaptively according to the network performance (call-blocking probability) measured in real-time. In simulation experiments, the performance of this method is comparable to that of the off-line-based method--especially when highly efficient dynamic routing is used. This paper also derives and describes methods for approximating the implied costs for multiclass-of-service networks. The approximations are very useful not only for off-line-based routing domain definition (RDD) methods but also for other kinds of network controls or optimal network dimensioning based on the concept of revenue optimization.

Although Hidden Markov Modeling (HMM) is widely and successfully used in many speech recognition applications, duration control for HMMs is still an important issue in improving recognition accuracy since a HMM places no constraints on duration. For compensating this defect, some duration control algorithms that employ precise duration models have been proposed. However, they suffer from greatly increased computational complexity. This paper proposes a new state duration control algorithm for limiting both the maximum and the minimum state durations. The algorithm is for the HMM trellis likelihood calculation, not for the Viterbi calculation. The amount of computation required by this algorithm is only order one (O(1)) for the maximum state duration n; that is, the computation amount is independent of the maximum state duration while many conventional duration control algorithm require computation in the amount of order n or order n2. Thus, the algorithm can drastically reduce the computation needed for duration control. The algorithm uses the property that the trellis likelihood calculation is a summation of many path likelihoods. At each frame, the path likelihood that exceeds the maximum likelihood is subtracted, and the path likelihood that satisfies the minimum likelihood is added to the forward probability. By iterating this procedure, the algorithm calculates the trellis likelihood efficiently. The algorithm was evaluated using a large-vocabulary speaker-independent spontaneous speech recognition system for telephone directory assistance. The average reduction in error rate for sentence understanding was about 7% when using context-independent HMMs, and 3% when using context-dependent HMMs. We could confirm the improvement by using the proposed state duration control algorithm even though the maximum and the minimum state durations were not optimized for the task (speaker-independent duration settings obtained from a different task were used).

Recenty, the Josephson effect-based voltage standard has been realized by using the Josephson junction array which is constructed by integrating many Josephson junctions. In this article, the 1-V Josephson-junction-array voltage standard used in routine calibration work and further development of the 10-V Josephson junction array at the Electrotechnical Laboratory (ETL) are introduced.

High-Tc superconducting flux flow transistors were fabricated with co-evaporated thin films of YBaCuO. The vortex flow channels (2 µm in width) and the device patterns were formed by Ar ion milling. The three-terminal characteristics, vortex flow characteristics, transresistance, and current gain of the device were measured. The AC input-output characteristics of the device with an Au load resistor were also measured. The measured flow voltage, transresistance and current gain are discussed in relation to these AC input-output measurements.

This paper considers properties of language classes with finite elasticity in the viewpoint of set theoretic operations. Finite elasticity was introduced by Wright as a sufficient condition for language classes to be inferable from positive data, and as a property preserved by (not usual) union operation to generate a class of unions of languages. We show that the family of language classes with finite elasticity is closed under not only union but also various operations for language classes such as intersection, concatenation and so on, except complement operation. As a framework defining languages, we introduce restricted elementary formal systems (EFS's for short), called max length-bounded by which any context-sensitive language is definable. We define various operations for EFS's corresponding to usual language operations and also for EFS classes, and investigate closure properties of the family Ge of max length-bounded EFS classes that define classes of languages with finite elasticity. Furthermore, we present theorems characterizing a max length-bounded EFS class in the family Ge, and that for the language class to be inferable from positive data, provided the class is closed under subset operation. From the former, it follows that for any n, a language class definable by max length-bounded EFS's with at most n axioms has finite elasticity. This means that Ge is sufficiently large.

Computational approaches to concept formation often share a top-down, incremental, hill-climbing classification, and differ from each other in the concept representation and quality criteria. Each of them captures part of the rich variety of conceptual knowledge and many are well suited only when the object-attribute distribution is not sparse. Formal concept analysis is a set-theoretic model that mathematically formulates the human understanding of concepts, and investigates the algebraic structure, Galois lattice, of possible concepts in a given domain. Adopting the idea of representing concepts by mutual closed sets of objects and attributes as well as the Galois lattice structure for concepts from formal concept analysis, we propose an approach to concept formation and develop OSHAM, a method that forms concept hierarchies with high utility score, clear semantics and effective even with sparse object-attribute distributions. In this paper we describe OSHAM, and in an attempt to show its performance we present experimental studies on a number of data sets from the machine learning literature.

This paper discusses an all-optical tank circuit that uses the comb-shaped gain spectrum generated by a Brillouin amplifier. The theory of timing clock extraction is shown for two cases: with two gains and with three gains. In both cases, the waveform of the extracted timing clock is simulated. According to the simulation, unlike an ordinary tank circuit, the amplitude of the extracted clock is not constant even though the quality factor (Q) is infinite. The extracted clock is clearly influenced by the pattern of the original data stream if the Brillouin gain is finite. The ratio of the maximum extracted clock amplitude to the minimum extracted amplitude is calculated as a function of Brillouin gain. The detuning of the pump light frequency is also discussed. It induces not only changes in the Brillouin gain, but also phase shift in the amplified light. The relation between the frequency drift of the pump lights and the jitter of the extracted timing clock is shown, in both cases: two pump lights are used and three pump lights are used. It is numerically shown that when the all pump lights have the same frequency drift, i.e., their frequency separation is constant, the phase of the extracted clock is not influenced by the frequency drift of the pump lights. The operation principle is demonstrated at 5Gbit/s, 2.5Gbit/s, and 2Gbit/s using two pumping techniques. The parameters of quality factor and the suppression ratio in the baseband domain are measured. Q and the suppression ratio are found to be 160 and 28dB, respectively.

Cross-phase modulation (XPM) induced by residual intensity modulation in coherent optical frequency-shift-keying (FSK) frequency division multiplexing (FDM) transmission systems that use dispersion-shifted fibers is evaluated theoretically and experimentally in terms of spectral profile deformation. The bit-error rate is measured in a 2.5-Gbit/s 4-channel 40-km dispersion-shifted fiber transmission experiment, and we confirm experimentally and theoretically that the power penalty in the presence of residual intensity modulation of over 4 mWp-p exceeds 1dB. Experimental results show that the penalty due to XPM is large even when the power of the newly generated lights caused by four-wave mixing is 20-dB less than that of signals. This confirms that residual intensity modulation must be reduced in continuous-phase (CP)-FSK-FDM systems even though they are designed to avoid generating four-wave mixing.

Recent technical advances in WDM (Wavelength Division Multiplexing) technologies suggest that their practical application is imminent. By adopting WDM technologies in the transport network, a bandwidth abundant B-ISDN could be realized cost-effectively. This requires the introduction of WDM technologies, especially into the path layer. This paper explores optical path cross-connect (OPXC) nodes that offer very high levels of expandability because existing traffic demands, which are rather limited, must be efficiently supported while permitting easy step-wise expansion in capacity. This paper highlights modularity with regard to incoming/outgoing links. The OPXC architecture that offers the highest modularity is elaborated, and its transmission characteristics, optical loss and switching power consumption are evaluated. This paper also examines OPXC architecture considering the interface needed to connect electrical path cross-connects. The proposed OPXC architectures provide flexibility and minimum investment to encourage the early introduction of B-ISDN and also supports incremental network growth to match traffic demand. The design of OPXC parameters in terms of transmission performance is shown to ensure the applicability of the proposed OPXC architecture to long-haul optical fiber transmission networks. This is made possible with the low optical component losses offered by the OPXC. The proposed OPXC architectures will, therefore, be applied not only to regional networks, but also to global area networks. Thus they will play a key role in realizing the optical path infrastructure for the future bandwidth abundant B-ISDN.

When communication network planning-design is performed, especially in a short-term case, it is important to utilize existing facilities in the construction of the new network. In this paper, link capacity assignment problem (CA problem) for packet-switched networks is investigated with the consideration of the existing network. To deal with this, per-unit cost of existing link capacity is thought to be less than that of newly installed capacity and a link cost function is modeled by a non-linear, non-differentiable one which is composed of two portions of capacity cost. After formulating the CA problem, two optimum algorithms derived from Lagrange multiplier method are presented and a modified algorithm is used for solving the CA problem in order to reduce the computation time. Some numerical results show that according to the values of link traffic flows, there will be links whose capacities must be set equally to the existing values. Moreover, when link cost difference is introduced in the CA problem, the number of links that the capacities of which have to be changed from existing values is less than that of linear cost function case, i.e., the case without consideration of the cost difference in link capacity.

A new approximation calculation method, named the Recursive Matrix-calculation (RM) method, is proposed. It uses matrix calculation to determine the number of link disjoint paths under a hop link number constraint, i.e. hop limit. The RM method does not overestimate the number of link disjoint paths. When networks are designed by this method, network reliability is perfectly guaranteed. Moreover, the RM method is based on matrix calculation, so CPU time can be reduced by using super-computers equipped with vector processors. Simulation results confirm that the RM method yields rapid approximations that are conservative. Thus the proposed method is very useful for designing reliable multimedia networks.