An ECL-CMOS SRAM technology is proposed which features a combination of ECL word drivers, ECL write circuits and low-voltage CMOS cells. This technology assures both ultra-high-speed and high-density. In the ECL-CMOS SRAM,various kinds of noise generated during the write cycle seriously affect the memory performance, because it has much faster access than conventional SRAMs. To overcome this problem, we propose three noise reduction techniques; a noise reduction clamp circuit, an emitter follower with damping capacitor and a twisted bit line structure with "normally on" equalizer. These techniques allow fast accese and cycle times. To evaluate these techniques, a 64-kb SRAM chip was fabricated using 0.5-µm BiCMOS technology. This SRAM has a short cycle time of 2 ns and a very fast access time of 1.5 ns. Evaluation proves the usefulness of these techniques.

The intensity-dependent transmission characteristics of an Ag+Na+ ion-exchanged glass waveguide with a nematic liquid crystal MBBA cover have been investigated experimentally using an Ar+ laser. It is found that the transmission characteristics of the TE1 mode are strongly influenced by temperature. Optical bistability has been observed at a particular temperature. Such the strong temperature dependence is believed to be brought by an increase in ordinary refractive index of the MBBA cover due to temperature rise.

For analyzing the transient electromagnetic fields caused by electrostatic discharge (ESD), a new ESD model is presented here. Numerical calculation is also given to explain the distinctive phenomenon being well-recognized in the ESD event.

This paper focuses on two areas in our effort to synthesize speech from neuromotor input using neural network models that effect transforms between cognitive intentions to speak, their physiological effects on vocal tract structures, and subsequent realization as acoustic signals. The first area concerns the biomechanical transform between motor commands to muscles and the ensuing articulator behavior. Using physiological data of muscle EMG (electromyography) and articulator movements during natural English speech utterances, three articulator-specific neural networks learn the forward dynamics that relate motor commands to the muscles and motion of the tongue, jaw, ant lips. Compared to a fully-connected network, mapping muscle EMG and motion for all three sets of articulators at once, this modular approach has improved performance by reducing network complexity and has eliminated some of the confounding influence of functional coupling among articulators. Network independence has also allowed us to identify and assess the effects of technical and empirical limitations on an articulator-by-articulator basis. This is particularly important for modeling the tongue whose complex structure is very difficult to examine empirically. The second area of progress concerns the transform between articulator motion and the speech acoustics. From the articulatory movement trajectories, a second neural network generates PARCOR (partial correlation) coefficients which are then used to synthesize the speech acoustics. In the current implementation, articulator velocities have been added as the inputs to the network. As a result, the model now follows the fast changes of the coefficients for consonants generated by relatively slow articulatory movements during natural English utterances. Although much work still needs to be done, progress in these areas brings us closer to our goal of emulating speech production processes computationally.

A new automated main distributing frame (AMDF) system is developed that reduces operating costs in metallic-cable main distributing frames (MDFs) used for communication networks. In this AMDF system, a robot inserts connecting-pins into the crosspoint holes of matrix-boards. This process allows jumpering to be completed within three minutes and the route-setting for line testing within one minute. The AMDF system provides approximately 2,100 office equipment cable-terminals. Parallel installation of several AMDF systems allows larger MDF systems to be constructed. This system reduces costs and achieves high reliability through three new technologies: high-density matrix-board, precision pin-handling, and a highly reliable system control. Test results for a prototype AMDF system confirm their effectiveness.

256 MbDRAM chips have been fabricated by mix-and-match method using high NA KrF excimer laser stepper and i-line stepper. In the case of KrF stepper, the negative siloxane resist is used for rectangular and wiring patterns and the positive novolak-resin resist is used for hole patterns. Both of these two kinds of resist produce accurate pattern shape, allow-able pattern profile, satisfactory depth of focus and sufficient overlay accuracy for device fabrication in 0.25 µm design rule.

In this paper we present a method to generate test sequences for stuck-at faults in sequential circuits which have distinguishing sequences. Since the circuit may have no distinguishing sequence, we use two design techniques for circuits which have distinguishing sequences. One is at state transition level and the other is at gate level. In our proposed method complete test sequence can be generated. The sequence consists of test vectors for the combinational part of the circuit, distinguishing sequences and transition sequences. The test vectors, which are generated by a combinational test generator, cause faulty staes or faulty output responses for a fault, and disinguishing sequences identify the differences between faulty states and fault free states. Transition sequences are necessary to make the state in the combinational vectors. And the distinguishing sequence and the transition sequence are used in the initializing sequence. Some techniques for shortening the test sequence is also proposed. The basic ideas of the techniques are to use a short initializing sequence and to find the order in concatenating sequences. But fault simulation is conducted so as not to miss any faults. The initializing sequence is obtained by using a distinguishing sequence. The efficiency of our method is shown in the experimental results for benchmark circuits.

The propagation characteristics of nonlinear TE waves guided by planar optical waveguide whose guiding region has arbitrary inhomogeneous refractive-index profile are investigated theoretically by using the WKB method. The effects of inhomogeneous index profile of a guided region on the propagation characteristics such as the propagation constant and the field distribution are estimated numerically.

Recently, a flexible image database retrieval system where image keywords can be captured automatically is strongly required, in order to manage a practical number of image data successfully. However, image recognition/understanding technology level is not generally sufficient enough to achieve this requirement. In order to overcome this problem, a new type of image database framework is proposed in this paper. In the proposed system, image keywords are extracted in fully-automated fashion by the flexible and generalized image recognition system. Image keywords employed in this system are a collection of recognized objects in the image, where achieved recognition levels are allowed to be intermediate or imperfect. The concept of recognition thesaurus" has been introduced to manage these various abstraction level of kerwords successfully. As an embodiment of this concept, an experimental image database with various types of sports scenes has been implemented and various retrieval evaluations have been performed. Experimental results reveal the effectiveness of the proposed method.

This paper presents a linear time optimal algorithm to a channel pin assignment problem for hierarchical building-block layout design. The channel pin assignment problem is to determine positions of the pins of nets on the top and the bottom sides of a channel, which are partitioned into several intervals, and the pins are permutable within their associated intervals. The channel pin assignment problem has been shown NP-hard in general. We present a linear time optimal algorithm for an important special case of the problem, in which there is at most one pin of a net within each interval in the channel. The proposed algorithm is optimal in a sense that it can minimize both the channel density and the total wire length of the channel. We also disscuss how to apply our algorithm to the pin assignment in the L-shaped and staircase channels. Experimental results indicate that substantial reduction in both channel density and estimated total wire length can be obtained by permuting pins in each interval. Combining the proposed algorithm with a conventional channel router, results of channel routing also achieve large amount of reduction of the number of tracks, total wire length, and the number of vias.

The synchronic distance is a fundamental concept in a Petri net. Marked graphs form a subclass of Petri nets. Given a matrix D, we are interested in the problem of finding a marked graph whose synchronic distance matrix is D. It is wellknown that the synchronic disrance matrix of a marked graph is a distance matrix. In this letter, we give a matrix D such that D is a distance matrix and there does not exist a marked graph whose synchronic distance matrix is D.

The antennas for subsurface radar are usually covered with a conducting cavity to prevent the radiation field from affecting the electromagnetic environment and to protect the received field from external noises. Furthermore, radiowave absorber is attached to the interior wall of the cavity in order to suppress the multiple reflections in the cavity. In this paper, the characteristics of the two-dimensional cavity-backed antenna having the absorber and the over-all properties of this subsurface radar due to buried objects are numerically analyzed by the Finite-Difference Time-Domain method. It is shown that the pulse propagation in the ground is confined to the narrow region due to the cavity. It is also shown that the multiple reflections in the cavity are effectively suppressed by choosing the suitable absorber, and so that the distinctive pulse echo can be obtained.

High performances of CMOS/SOI inverter by simulations of analytical model, reducing the poly-Si gate thickness (tm), and experiments are verified and proposed. It is shown that the tm and gate oxide thickness(tox) are correlated to gate fringing capacitance, which largely influences on the Propagation Delay Time(TPD). Contributions of gate fringing capacitance to CMOS/SIMOX inverter time delay in deep submicrometer gate devices are propounded. Measurements of the fifty-one stage ring oscillator's TPDs are completed for comparison with analytical model. Simulation results by the analytical model, including Time-Dependent Gate Capacitance (TDGC) model, agree well with the experimental results at the same conditions. Simulation results are also predicted that SOI technology is promising for speed enhancement by reducing the poly-Si gate thickness, while the tox remains constant. It is concluded that the TPDs by reducing the tm to zero are improved up to about two times faster than typically fabricated ring oscillator at 350 nm of the tm in deep-submicrometer gate CMOS/SIMOX inverters at room temperature.

Poled polymer films doped with novel nonlinear organic materials, α-cyano unsaturated carboxylic acid (α-CUCA) derivatives, are prepared. Linear and second-order nonlinear optical properties are investigated. It is found that as the value of hyperpolarizability of the derivatives increases, the second-order nonlinear susceptibility of the film increases. Cerenkov-type second harmonic generation (SHG) of Nd: YAG laser is realized in a poled polymer waveguide doped with the α-CUCA material with a slight absorption at doubled wavelength.

The fast and highly reliable method reported here uses two techniques to detect all types of defects, such as unsoldered leads, solder bridges, and misalignes leads in the minute solder joints of high density mounted devices. One technique uses external force applied by an air jet that vibrates or shifts unsoldered leads. The vibration and shift is detected as a change in the speckle pattern produced by laser illumination of the solder joints. The other technique uses fluorescence generated by short-wavelength laser illumination. The fluorescence from a printed circuit board produces a silhouette of the solder joint and this image is processed to detect defects. Experimental results show that this inspection method detects all kinds of defects accurately and with a very low false alarm rate.

We present an extension of the previously proposed 3-layer feedforward network called a cascaded network. Cascaded networks are trained to realize category classification employing binary input vectors and locally represented binary target output vectors. To realize a nonlinearly separable task the extended cascaded network presented here is consreucted by introducing high order cross producted inputs at the input layer. In the construction of the cascaded network, two 2-layer networks are first trained independently by delta rule and then cascaded. After cascading, the intermediate layer can be understood as a hidden layer which is trained to attain preassigned saturated outputs in response to the training set. In a cascaded network trained to categorize binary image patterns, saturation of hidden outputs reduces the effect of corrupted disturbances presented in the input. We demonstrated that the extended cascaded network was able to realize a nonlinearly separable task and yielded better generalization ability than the Backpropagation network.

A systematic theory of the optimum sub-band interpolation using parallel wavelet filter banks presented with respect to a family of n-dimensional signals which are not necessarily band-limited. It is assumed that the Fourier spectrums of these signals have weighted L2 norms smaller than a given positive number. In this paper, we establish a theory that the presented optimum interpolation functions satisfy the generalized discrete orthogonality and minimize the wide variety of measures of error simultaneously. In the following discussion, we assume initially that the corresponding approximation formula uses the infinite number of interpolation functions having limited supports and functional forms different from each other. However, it should be noted that the resultant optimum interpolation functions can be realized as the parallel shift of the finite number of space-limited functions. Some remarks to the problem of distinction of images is presented relating to the generalized discrete orthogonality and the reciprocal property for the proposed approximation.

High speed simulation of neural networks can be achieved through parallel implementations capable of exploiting their massive inherent parallelism. In this paper, we show how this inherent parallelism can be effectively exploited on parallel data-driven systems. By using these systems, the asynchronous parallelism of neural networks can be naturally specified by the functional data-driven programs, and maximally exploited by pipelined and scalable data-driven processors. We shall demonstrate the suitability of data-driven systems for the parallel simulation of neural networks through a parallel implementation of the widely used back propagation networks. The implementation is based on the exploitation of the network and training set parallelisms inherent in these networks, and is evaluated using an image data compression network.

Since, in a VLSI circuit, the number of transistors and the clock frequency are constantly increasing, it is important to analyze the voltage drop and current density on a full chip's power networks. We propose a new hierarchical power analysis system named XPOWER. A new reduction algorithm for the resistance and current source network is used in this system. The algorithm utilizes the design hierarchy in nature and is independent of network topology. Networks at each level are reduced into small and equivalent networks, and this reduction is performed recursively from the bottom levels of the design hierarchy. At each step of the reduction, the network under consideration consists of two kinds of objects: (1) reduced child networks, and (2) the interconnection between child networks. After all networks have been reduced, circuit equationa are solved recursively from the top. This allows to decrease the size of the matrix to be solved and to reduce the execution time. Experimental results show that the factor of reduction in matrix size is from 1/10 to 1/40 and execution is six times faster than with flat analysis. The power networks of a 16 bit digital signal processor was analyzed within 15 minutes using XPOWER.

A new system of measuring the thickness of thin filn or paper using 40 kHz ultrasonic wave in air is described. The thickness of samples measured is smaller by a factor of sevreal hundreds than the wavelength of sound. Experinents with polymer and metal films and paper are described to demonstrate the measurement possibilities.