Soliton transmission control has already proved to be an outstanding technique and enable a soliton to be transmit over one million kilometers. This technique is not only applicable to vast distances but also to shorter distances where the amplifier spacing is greater than that of conventional systems. A combination of time and frequency domain control eliminates the noise accumulation and timing jitter caused by soliton interaction and the Gordon-Haus effect, that are the main impediments to extending the transmission distance. In this paper we describe soliton control techniques applied over an astronomical transmission distance of 180,000,000 km, and to a terrestrial system with a large amplifier spacing of up to 100km. We also report the possibility of realizing a sub-tera bit/s soliton transmission system operating over more than 5,000 km in which the soliton self-frequency shift is controlled with the soliton control technique.

We are studying a novel concept of the on-line hospital system using a virtual environment called Hyper Hospital," the Hyper Hospital" is a medical care system which is constructed in a distributed manner to the electronic information network using virtual reality (VR) as a human interface. In the present report, we studied the physiological and psychological responses of healthy subjects induced by the usage of the VR in terms of fatigue. Twenty healthy young male subjects were exposed to the virtual reality system and they performed some psychological tasks with a virtual nurse for 30 minutes. Several parameters of physiological, psychological, and subjective fatigue were measured. None of the physiological or psychological parameters such as urinary catecholamine release, ECG, etc. showed significant fatigue induced by our VR system. However, by using a standard questionnaire, some kinds of subjective fatigue were noted and they were thought to be indicating a direction of improvement for our VR system.

High performance I/O circuits for fast memory devices such as Synchronous DRAMs were studied. For a TTL interface, the effect of capacitive loading must increase as I/O speed is increased, and signal termination is required for frequencies over 100 MHz. For this reason, industry-proposed alternative interface approaches such as GTL and CTT were investigated using experimental test devices. The results showed that open-drain type drivers have a problem; as the frequency increases, the high-level output voltage becomes degraded. In contrast, a push-pull driver T-LVTTL (Terminated Low Voltage TTL), developed as an implementation of the CTT interface specification, was found to be suitable for high-speed data transfer. A high-speed bus driver circuit connecting an impedance element in series to the stub is proposed as an application of T-LVTTL. Simulated results showed that this scheme greatly improves the signal integrity of memory bus systems; the operating frequency could very well be the highest among several schemes discussed as candidates for the post-LVTTL standard interface.

The Hyper Hospital" is a novel medical care system which will be constructed on an electronic information network. The human interface of the Hyper Hospital based on the modern virtual reality technology is expected to enhance patients' ability to heal by providing computer-supported on-line visual consultations. In order to investigate the effects and features of on-line visual consultations in the Hyper Hospital, we conducted an experiment to clarify the influence of electronic interviews on the talking behavior of interviewees in the context of simulated doctor-patient interactions. Four types of distant-confrontation interviews were made with voluntary subjects and their verbal and non-verbal responses were analyzed from the behavioral point of view. The types of interviews included three types of electronic media-mediated interviews and one of a live face to face interview. There was a tendency in the media-mediated interviews that both the latency and the duration of interviewees' utterances in answering questions increased when they were compared with those of live face to face interviews. These results suggest that the interviewee became more verbose or talkative in the media-mediated interviews than in the live interviews. However, the interviewee's psychological tension was generally augmented in the media-mediated interviews, which was suggested by the delay of the initiation of conversations as compared to the conventional face-to-face interviews. We also discuss the applicability of media-mediated interviews by an electronic doctor which we are studying as a functional unit of our Hyper Hospital, a network based virtual reality space for medical care.

Transistor stuck–open faults in CMOS devices are such that they force combinational circuits to exhibit sequential behaviors. It has been proved that, in general, stuck–open faults can not be modeled as stuck–at faults and, therefore, a sequence of two consecutive test vectors is necessary to guarantee stuck–open fault detection. In this paper we propose a technique to modify CMOS circuits in such a way that any stuck–open fault in the circuit can be detected using only a single test pattern. The amount of additional logic required to achieve the goal is rather limited: Two pass transistors, one input line, and one inverter (or buffer) at the output of the circuit are sufficient to make stuck–open faults detectable by test patterns generated by usual stuck–at fault test generators.

The design theory was revealed by theoretical analysis of the measuring apparatus, and was confirmed experimentally. Higher quality tags having new circuit disigns were proposed by the revealed theory. The measuring apparatus equivalent to the security system was produced to estimate the properties of the LC resonant circuit security tags quantitatively.

A particle trajectory estimation method from far electromagnetic fields are discussed in this paper. Authors have already presented a trajectory estimation method for single particle system and good agreements between a source particle trajectory and an estimated one have been obtained. For this, this paper discusses twin particles system as an examples of multi-particles systems for simplicity. First of all, it is pointed out that far electromagnetic fields from the twin particles system show quite different aspect from the single particle system using an example, radiation patterns produced by two particles which carry out circular motion. This result tells us that any trajectory estimations for general multi-particles system are almost impossible. However, it is shown that when the distance between the particles is small, the estimation method for the single particle system can be applied to the twin particles system, and that twin particles effects appear as disturbance of estimated trajectory.

This paper describes a new method for pose estimation of human face moving abruptly in real world. The virtue of this method is to use a very simple calculation, disparity, among multiple model images, and not to use any facial features such as facial organs. In fact, since the disparity between input image and a model image increases monotonously in accordance with the change of facial pose, view direction, we can estimate pose of face in input image by calculating disparity among various model images of face. To overcome a weakness coming from the change of facial patterns due to facial individuality or expression, the first model image of face is detected by employing a qualitative feature model of frontal face. It contains statistical information about brightness, which are observed from a lot of facial images, and is used in model-based approach. These features are examined in everywhere of input image to calculate faceness" of the region, and a region which indicates the highest faceness" is taken as the initial model image of face. To obtain new model images for another pose of the face, some temporary model images are synthesized through texture mapping technique using a previous model image and a 3-D graphic model of face. When the pose is changed, the most appropriate region for a new model image is searched by calculating disparity using temporary model images. In this serial processes, the obtained model images are used not only as templates for tracking face in following image sequence, but also texture images for synthesizing new temporary model images. The acquired model images are accumulated in memory space and its permissible extent for rotation or scale change is evaluated. In the later of the paper, we show some experimental results about the robustness of the qualitative facial model used to detect frontal face and the pose estimation algorithm tested on a long sequence of real images including moving human face.

A method is presented for reconstructing the surface profile of a perfectly conducting rough surface boundary from the measurements of the scattered far-field. The proposed inversion algorithm is based on the use of the Kirchhoff approximation and in order to determine the surface profile, the Fletcher-Powell optimization procedure is applied. A number of numerical results illustrating the method are presented.

A new leaky surface wave on lithium tetraborate that propagates along the surface with a higher phase velocity than that of ordinary leaky surface waves, radiating two bulk wave terms into the solid, is described.

This paper describes a high-density, high-pin-count flexible SMD connector used for high-speed data buses between MCMs or daughter boards. This connector consists of a flexible film cable interconnection with accurately controlled characteristic impedance, and a contact housing composed of double-line contacts and SMD type leads. It has 98 contacts each with a pitch of 0.4 mm. The connector mounting area is 6 mm wide and 23 mm long. The flexible cable has a double-sided triple-parallel micro stripline structure with an insertion force of less than 2.9 kgf and characteristic impedance of 48 to 50 Ω. Insertion loss is -0.5 dB at 600 MHz and crosstalk noise is less than 110 mV at 250 ps rising time. This connector can be used for high-speed data transmission of up to 300 ps rising time.

Management of control functions in large computer networks is a very difficult problem. One of the effective way to overcome the difficulty is to introduce hierarchical control structure (network cluster) in the management. When a fault occurred in the cluster, routing information at some nodes in the network must be updated in order to react the fault. However, the number of such nodes can be reduced by introducing ingenious topology into the cluster. This paper presents a fundamental discussion on network topology for a network cluster. First, L-FT is defined to represent a degree of fault-tolerance in a cluster with respect to link failures. Secondly, the minimum link problem M is defined to find the minimum number of links to make the cluster L-FT. The following results are obtained. (1) For a network cluster with the fault-tolerant topology 1-FT, at least 2n-2 links have to exist in the cluster where n is the number of border nodes in the cluster. (2) As far as connectivity of the whole network is held, for multiple L link failures in a L-FT cluster, the update of routing information at each node is localized within only the cluster containing the failed links. (3) Several hierarchical networks with fault-tolerant conditions are presented as case studies for a LAN and a MAN.

This paper describes the optical characteristics and static fatigue reliability of a zirconia alignment sleeve, which is a component part of an optical connector with zirconia ferrules. This combination of sleeve and ferrules hardly generates any wear debris during connector insertion and removal cycles. This has reduced the cleaning frequency of the ferrule endface during cycles and greatly improved the return loss stability of the optical connectors. The zirconia alignment sleeve enables stable return loss characteristics to be achieved over a wide temperature range as it has the same thermal expansion coefficient as the zirconia ferrule. Furthermore, the gauge retention force for the zirconia alignment sleeve is defined with a view to its practical use. This force must be between 2.0 and 3.9 N to allow stable optical connections to be made under various mechanical and environmental conditions. We also clarify the conditions for a proof test by which to prevent the occurrence of static fatigue fractures in the sleeve, and we confirm the validity of the test. The static fatigue parameters for zirconia ceramics and derived from the static fatigue theory for brittle materials and fracture testing. We use these static fatigue parameters to predict the lifetime of a zirconia sleeve under working stress. An appropriate stress level for the proof test which eliminates weak sleeves, is about 3 times greater than working stress. The strength of the sleeve as demonstrated in the proof test is confirmed by accelerative stress aging. The performance of this sleeve is superior to that of a conventional copper alloy sleeve and the proof test confirms its reliability; under 0.1 FIT for 20 years of use.

This paper describes a trial coaxial surface mounted connector for PGA-type high-speed multichip modules (MCM). An MCM connector is needed to ensure testability and connection reliability of MCMs mounted on a printed circuit board. Our connector consists of a coaxial elements, a common ground housing made of conductive resin, and a ground contact spring plate. It has 68 signal contacts. We investigated the performance of this connector by experiment and simulation. Its insertion force is only about 53 gf per signal pin. The characteristic impedance is from 45.6 Ω to 61.4 Ω. The average resistance between two contacts is 28 mΩ with a deviation of less than plus or minus 5 mΩ. The insertion is -0.4 dB at 1.0 GHz. Crosstalk noise is less than 1.2%. This prototype connector can transmit pulses of up to 1.2 Gb/s, showing that it is applicable to high-speed MCMs.

The relation between computing part of the FFT spectrum and the so-called generalized FFT (GFFT) is clarified, leading to a new algorithm for performing partial FFTs. The method can be applied when only part of the output is required or when the input data sequence contains many zeros. Such cases arize for example in decimation and interpolation and also in computing linear convolutions. The technique consists of decomposing the DFT into several generalized DFTs. Efficient algorithms for these generalized DFTs exist. The computational complexity of the new approach is roughly equal to the complexity of previous techniques, but the structure is superior, because only one type of butterfly is used and a few lines of code are sufficient. The theoretical properties of the GDFT are given. The case of multidimensional signals, defined on arbitrary sampling lattices is also considered.

In this paper, we present Branching Oriented System Equation based on-line error correction scheme for recursive digital signal processing. The target digital signal processing is linear and time-invariant, and the algorithm includes multiplications with constant coefficient, additions and delays. The difficulties of the algorithm-level fault tolerance for such algorithm without structural regularity include error distribution problem and right timing of error correction. To escape the error distribution problem, multiple fan-out nodes in an algorithm are specified as the nodes at which error corrections are performed. The Branching Oriented Graph and Branching Oriented System Equation are so introduced to formulate on-line correction schemes based on this strategy. The Branching Oriented Graph is treated as the collection of computation sub-blocks. Applying checksum code independently to each sub-block is our most trivial on-line error correction scheme, and it results in, with appropriate selection of error identification process, TMR in sub-block level. One of the advantages of our method is in the reduction of redundant operations performed by merging some computation sub-blocks. On the other hand, the schedulability of the system is an important issue for our method since our on-line error correction mechanism induces additional data dependencies. In this paper, the schedulability condition and some modifications on the scheme are also discussed.

In this paper, a fault model for multiple-valued programmable logic arrays (MV-PLAs) is proposed and the equivalences of faults of MV-PLA's are discussed. In a supposed multiple-valued NOR/TSUM PLA model, it is shown that multiple-valued stuck-at faults, multiple-valued bridging faults, multiple-valued threshold shift faults and other some faults in a literal generator circuit are equivalent or subequivalent to a multiple crosspoint fault in the NOR plane or a multiple fault of weights in the TSUM plane. These results lead the fact that multiple-valued test vector set which indicates all multiple crosspoint fault and all multiple fault of weights also detects above equivalent or subequivalent faults in a MV-PLA.

Exact analytical solutions for the steady-state transmission and reflection characteristics of a nonlinear Fabry-Perot resonator applicable to bistable optical devices are derived. The resonator consists of a Kerr-like nonlinear film sandwiched by reflection mirrors made of a quarter-wave dielectric stack. An equivalent mirrorless model has been introduced to facilitate the analysis. For both positive and negative nonlinear coefficients, the rigorous solutions have been simply expressed in terms of Jacobian elliptic functions.

This paper addresses a method for constructing surface representation of 3D structures from a sequence of cross-sectional images. Firstly, we propose cell-boundary representation, which is a generalization of PVP method proposed by Yun and Park, and develop an efficient surface construction algorithm from a cell-boundary. Cell-boundary consists of a set of boundary cells with their 1-voxel configurations, and can compactly describe binary volumetric data. Secondly, to produce external surface from the cell-boundary representation, we define 19 modeling primitives (MP) including volumetric, planar and linear groups. Surface polygons are created from those modeling primitives using a simple table look-up operation. Since a cell-boundary can be obtained using only topological information of neighboring voxels, there is no ambiguity in determining modeling primitives which may arise in PVP method. Since our algorithm has data locality and is very simple to implement, it is very appropriate for parallel processing.

In this paper we estimate the number of permutations realizable in fault-tolerant multistage interconnection networks designed to tolerate faults on any switching element. The Parallel Omega network and the INDRA network are representative types of fault-tolerate multistage interconnection networks designed to tolerate a single fault. In order to evaluate the enhancement in the function of network by preparing the hardware redundancy for fault-tolerance, we estimate the number of permutations realizable in fault-tolerant networks. This result enables us to set up a standard to evaluate the hardware redundancy required to tolerate multifaults from the viewpoint of the enhancement of network function. This paper concludes that in the case where the number of inputs is up to 32 the increase ratio of the number of realizable permutations is no more than 1/0.73 even if the tolerance to multifaults is prepared instead of the tolerance to a single fault.