A linear-in-dB VGA of the current-divider type is fabricated in 0.25 µm CMOS technology. Two gain compensation techniques are proposed in order to compensate the gain deviations due to a MOSFET which has a square-law characteristic or an exponential-law characteristic determined by its current density. Temperature compensation techniques are also proposed. Measure results obtained at 380 MHz are a gain range of 80 dB, a gain error of 3 dB, and an NF of 11 dB.

Utilizing a macromodel which calculates the floating gate potential by combining resistances and dependent voltage and current sources, DC transfer characteristics for multi-input neuron MOS inverters and for those in the neuron MOS full adder circuit are simulated both at room temperature and at 77 K. Based on the simulated results, low temperature circuit failures are discussed. Furthermore, circuit design parameter optimization both for low and room temperature operations is described.

In the study, we build a system called Adaptive Visual Attentive Tracker (AVAT) for the purpose of developing a non-verbal communication channel between the system and an operator who presents intended movements. In the system, we constructed an HMM (Hidden Markov Models)-based TD (Temporal Difference) learning algorithm to track and zoom in on an operator's behavioral sequence which represents his/her intention. AVAT extracts human intended movements from ordinary walking behavior based on the following two algorithms: the first is to model the movements of human body parts using HMMs algorithm, and the second is to learn the model of the tracker's action using a model-based TD learning algorithm. In the paper, we describe the integrated algorithm of the above two methods: whose linkage is established by assigning the state transition probability in HMM as a reward in TD learning. Experimental results of extracting an operator's hand sign action sequence during her natural walking motion are shown which demonstrates the function of AVAT as it is developed within the framework of perceptual organization. Identification of the sign gesture context through wavelet analysis autonomously provides a reward value for optimizing AVAT's action patterns.

Fully embedded spiral inductors in a low loss dielectric multi-layer were designed and fabricated using a low temperature co-fired ceramics (LTCC) technology for RF SIP (system in package) integrations. The line width/space and the number of spiral layers were optimized within five layers of LTCC dielectric for high Q-factor, high self-resonant frequency (SRF), process easiness, and compact size. The embedded multi-layer spiral inductors reveal better performance in terms of Q-factor, SRF and the effective inductance Leff than planar spiral inductors of the same dimension and number of turns. The optimized multi-layer spiral inductor shows maximum Q of 56, Leff of 6.6 nH at Qmax and SRF of 3.6 GHz while planar spiral inductors have maximum Q of 49, Leff of 5.8 nH at Qmax and SRF of 3.0 GHz.

We report field emission from multilayered cathodes grown on silicon and glass substrates. The cathode consist of a layer of nanoseeded diamond and overlayers of nanocluster carbon (sp2 bonded carbon) and tetrahedral amorphous carbon (predominantly sp3 bonded carbon). These films exhibit good field emission characteristics with an electron emission current density of 1µA/cm2, at a field of 5.1V/µm. The multilayered cathodes on silicon substrates exhibit even lower emission threshold field of about 1-2V/µm for an emission current density of 1µA/cm2. The emission is influenced by the nanoseeded diamond size and concentration and the properties of the nano carbon over layer.

This paper presents a method of temporal decomposition (TD) for line spectral frequency (LSF) parameters, called "Modified Restricted Temporal Decomposition" (MRTD), and its application to low rate speech coding. The LSF parameters have not been used for TD due to the stability problems in the linear predictive coding (LPC) model. To overcome this deficiency, a refinement process is applied to the event vectors in the proposed TD method to preserve their LSF ordering property. Meanwhile, the restricted second order TD model, where only two adjacent event functions can overlap and all event functions at any time sum up to one, is utilized to reduce the computational cost of TD. In addition, based on the geometric interpretation of TD the MRTD method enforces a new property on the event functions, named the "well-shapedness" property, to model the temporal structure of speech more effectively. This paper also proposes a method for speech coding at rates around 1.2 kbps based on STRAIGHT, a high quality speech analysis-synthesis method, using MRTD. In this speech coding method, MRTD based vector quantization is used for encoding spectral information of speech. Subjective test results indicate that the speech quality of the proposed speech coding method is close to that of the 4.8 kbps FS-1016 CELP coder.

Though, high dielectric constant material is a possible near future solution in order to suppress gate current densities of MOSFETs, the barrier height generally decreases with an increasing dielectric constant. In this paper, the injection current through gate stacks has been calculated while taking into account the electron temperature using the W.K.B. method to understand the impact of the injection current from the drain edge.

To measure temperature dependent complex permittivity of dielectric materials, a rectangular cavity resonator with a heating system has been developed. In the experiment, microwave power with the frequency of 2.45 GHz is applied to heat the dielectric material. In order to reduce the error of the complex permittivity of dielectric material obtained from the perturbation method, an electromagnetic (EM) field simulator is applied which uses the Transmission Line Modeling (TLM) method. The uniformity of the temperature is also discussed by the use of heat transfer equation which applies the results of TLM simulation. It is found from the results that the accurate temperature dependence of complex permittivity of the material can be obtained by the method presented here.

When we use an adaptive array antenna (AAA) with the minimum mean square error (MMSE) criterion under the multipath environment, where the receiving signal level varies, it is difficult for the AAA to converge because of the distortion of the desired wave. Then, we need the equalization both in space and time domains. A tapped-delay-line adaptive array antenna (TDL-AAA) and the AAA with linear equalizer (AAA-LE) have been proposed as simple space-temporal equalization. The AAA-LE has not utilized the recursive least square (RLS) algorithm. In this paper, we propose a space-temporal simultaneous processing equalizer (ST-SPE) that is an AAA-LE with the RLS algorithm. We proposed that the first tap weight of the LE should be fixed and the necessity of that is derived from a normal equation in the MMSE criterion. We achieved the space-temporal simultaneous equalization with the RLS algorithm by this configuration. The ST-SPE can reduce the computational complexity of the space-temporal joint equalization in comparison to the TDL-AAA, when the ST-SPE has almost the same performance as the TDL-AAA in multipath environment with minimum phase condition such as appeared at line-of-sight (LOS).

Among ITS applications, it is very important to acquire detailed statistics of traffic flows. For that purpose, vision sensors have an advantage because of their rich information compared to such spot sensors such as loop detectors or supersonic wave sensors. However, for many years, vehicle tracking in traffic images has suffered from the problems of occlusion effect and illumination effect. In order to resolve occlusion problems, we have been proposing the Spatio-Temporal Markov Random Field model(S-T MRF) for segmentation of Spatio-Temporal images. This S-T MRF model optimizes the segmentation boundaries of occluded vehicles and their motion vectors simultaneously by referring to textures and segment labeling correlations along the temporal axis as well as the spatial axis. Consequently, S-T MRF has been proven to be successful for vehicle tracking even against severe occlusions found in low-angle traffic images with complicated motions, such at highway junctions. In addition, in this paper, we define a method for obtaining illumination-invariant images by estimating MRF energy among neighbor pixel intensities. These illumination-invariant images are very stable even when sudden variations in illumination or shading effect are occurred in the original images. We then succeeded in seamlessly integrating the method for MRF energy images into our S-T MRF model. Thus, vehicle tracking was performed successfully by S-T MRF, even against sudden variations in illumination and against shading effects . Finally, in order to verify the effectiveness of our tracking algorithm based on the S-T MRF for practical uses, we developed an automated system for acquiring traffic statistics out of a flow of traffic images. This system has been operating continuously for ten months, and thus effectiveness of the tracking algorithm based on S-T MRF model was proven.

This paper describes the behavior of voids that were formed due to electromigration and diffusion in the interconnections of gold during a DC bias tests of GaAs ICs to current densities in the interconnections of 0.67 106 A/cm2 to 1.27 106 A/cm2 in the high temperature range of 230 to 260. We have found that the voids were formed at the centers in the cross sections of the interconnections and that gold is left around the voids, which means current still flows after the void formation. We have carefully observed the movement of the anode and cathode side edge of the voids during the tests and found that edges moved toward the cathode, in the direction opposite to the electron flow. This direction is constant. Also, the voids are extended, which means that the velocity of the cathode side edge is greater than that of the anode side edge. The velocity of the edges almost proportionally increased with the current density. The constant edge movement direction and the velocity of the edge dependence on the current density suggest that one of the causes of the edge movement is electromigration. The velocity of the edge depends on the distance between the anode side edge of the void and the through hole. The velocity increases in accordance with a decrease in the distance. This means that one of the causes of the edge movement is the diffusion of gold atoms by a concentration and pressure gradient. The GaAs IC failed at almost the same time as the voids appeared. It is important for reliability to prevent the formation of voids caused by electromigration and diffusion.

Low-temperature poly-Si thin film transistor with gate-overlapped LDD (GOLD) structure was fabricated. Reliability was evaluated using electrical stress method comparing conventional LDD and single drain structures. As previous researchers have reported, we have confirmed that the degradation of ON current and the field effect mobility was very small compared to conventional LDD or non-LDD structures. We have analyzed the reliability of the GOLD TFT using two-dimensional device simulator. We have clarified that vertical negative field plays a dominant role for improving the reliability in the GOLD TFT. Impact ionization occurs far from the interface between the oxide and poly-silicon by the vertical negative field. GOLD structure is promising for the realization of system on panel.

We developed a new method to improve the efficiency of the PDP (plasma display panel) by the use of a novel protecting film or Gd doped MgO film. In the cells of the PDP, the VUV (vacuum ultraviolet ray) is generated by Xe discharge. The VUV is simply absorbed by the protecting film or MgO film. Therefore, normally the absorbed VUV doesn't contribute to the light conversion efficiency. However, the novel protecting film or MgO:Gd film radiates the ultraviolet ray of which 317 nm wavelength, by the irradiation of the shorter wavelength VUV, and it excites the blue phosphor. Consequently the efficiency of blue emission is improved.

Recent physiological studies on synaptic plasticity have shown that synaptic weights change depending on fine timing of presynaptic and postsynaptic spikes. Here, we show that a phenomenon similar to stochastic resonance with respect to background noise is observed on spike-timing dependent synaptic plasticity (STDP) that can contribute to stable propagation of precisely timed spikes in a multi-layered feedforward neural network.

Cellular Neural Networks (CNNs) have been developed as a high-speed parallel signal-processing platform. In this paper, a generalized two-layer cellular neural network model is proposed for image processing, in which two templates are introduced between the two layers. We found from the simulations that the two-layer CNNs efficiently behave compared to the single-layer CNNs for the many applications of image processing. For examples, simulation problems such as linearly non-separable task--logic XOR, center point detection and object separation, etc. can be efficiently solved with the two-layer CNNs. The stability problems of the two-layer CNNs with symmetric and/or special coupling templates are also discussed based on the Lyapunov function technique. Its equilibrium points are found from the trajectories in a phase plane, whose results agree with those from simulations.

We describe a method of compensating temperature fluctuation by a linear-time-warping processing in a sound reproduction system. This technique is applied to impulse responses of room transfer functions, to achieve a high-quality sound reproduction system, particularly one that treats high-frequency components. First, the impulse responses are measured before and after temperature fluctuation, and the former are converted to the latter by the proposed process. Next, we design inverse filters for the system, and evaluate the improvement of the reproduction accuracy and spectrum distortion. By the compensation method, we can improve the reproduction accuracy at any frequency. Moreover, we propose an adaptive algorithm for the estimation of a suitable warping ratio, using the observed signal of reproduced sound obtained at only one control point. Using the proposed algorithm, we can improve the reproduction accuracy at each control point by about 14 dB, in which a difference in temperature is 1.4.

A coaxial cable measurement system applicable up to 60 GHz in the cryogenic temperature is developed by using V-connectors. In this system, the fine location of coupling loop antennas can be adjusted by three-dimensional mechanical stages in the low temperature region. In order to verify usefulness of this system, the temperature dependence of surface resistance (Rs) of Y-Ba-Cu-O (YBCO) films was measured at 30 GHz by the two-dielectric resonator method using TE011- and TE013- mode sapphire rod resonators. The measured result of Rs was 0.5 mΩ at 30 GHz and 20 K, which was 1/40, compared with those of copper plates.

The non-linear quasiparticle tunnel current flowing in a distributed superconductor-insulator-superconductor (SIS) transmission line resonator has been exploited in a low-noise heterodyne fixed-tuned waveguide receiver in the 600-700 GHz band. The mixer employs two half-wave or full-wave distributed SIS long junctions connected in series. These devices have been fabricated with optical lithography. At 654 GHz, a Y-factor of 1.79 has been recorded, corresponding to a double-side-band (DSB) receiver noise temperature of 198 K at an IF of 3 GHz.

We have designed a torque magnetometer using a 60-kG split-type superconducting magnet. A balance torque compensates the torque acting on a sample in the magnetic field. The feedback circuit for a sample direction consists of an optical position sensor, a moving coil, and a PID controller. We measured the coil current to know a sample torque. The whole torque machinery is directly rotated by a stepping motor of angular resolution 0.0036. An advantage of the torque apparatus is a wide dynamic range up to 1000 dyncm. The sample temperature can be controlled between 4 K and 300 K.

This paper presents a high-throughput VLSI architecture for LZFG data compression and decompression. To reduce the hardware cost and maintain both of the interior node and the leaf node numbering systems, we modify the original LZFG data structure. Compared to the original LZFG tree, the number of characters in our modified LZFG data structure must be greater than one to establish one new interior node down the root node into the new node. Meanwhile, this architecture employs a series of encoding cells with content addressable memory (CAM) to search the longest match and maintain the LZFG data tree during the encoding and decoding processes. By using the parallel design, the compressor and decompressor can keep a constant high bit rate to encode and decode one character per clock cycle, that is, it is directly proportional to the operating clock rate, but independent of the sizes of the word dictionary and the input file. By using 0.25 µm CMOS silicon technology, the operating clock rate can be as high as 85 MHz. Some untargeted encoding cells will be disabled to reduce the power consumption during the comparison operation. Therefore, this architecture can be easily applied in the high-speed real-time communication and data storage systems.