We developed a compact rf receiver subsystem using a high-Tc superconducting sharp skirt band-pass filter with a center frequency tuning function. A 24-pole hairpin-type 2 GHz microstrip-line filter was fabricated with YBa2Cu3Oy thin films deposited on a LaAlO3 substrate. Attenuation characteristics were more than 30 dB at 1 MHz apart from both the lower and the higher pass-band edges. For center frequency tuning, a 1-mm-thick dielectric sapphire plate was stacked on the filter, and the filtering characteristics were tuned by moving the plate using a piezoelectric bending actuator. The range of the center frequency modulation was more than 12 MHz with no degradation of the low-loss and sharp-skirt characteristics.

Fiber-optic MEMS which is fabricated by combining direct photo-lithography of optical fiber and silicon micro-machining is proposed. Preliminary results of micro-machining of optical fiber and variable telecommunication devices are presented.

We present a new technique for hierarchical intellectual property (IP) protection using partially-mergeable cores. The proposed core partitioning technique guarantees 100% protection of critical-IP, while simplifying test generation for the logic that is merged with the system. Since critical-IP is tested using BIST, the controllability and observability of internal lines in the core are enhanced, and test application time is reduced. Case studies using the ISIT-DLX and Picojava processor cores demonstrate the applicability of our technique.

In mechanical splice technology, loss change during temperature cycling is mainly caused by fiber slippage or shift at the interface between fibers and fiber clamping substrates. The upper limit of the fabrication accuracy of the fibers and substrates restricts the total number of fibers in a splice. To overcome this, we propose a novel fiber clamping method using the elasticity of the substrate surface. We clamp the fibers more strongly at the fiber clamping ends, where the fibers need a greater friction force than around the butt-joint, to hold them in position. Taking the case of an 8-fiber ribbon splice, we compared linear marks on the substrates with the boundary linewidth curves for the onset of slippage. We achieved an insertion loss change of less than 0.1 dB during a temperature cycling test in accordance with Telcordia Technologies test specification. When we clamp fibers using the plasticity of the substrate surface, we can also reduce the required fabrication accuracy. However, insufficient accuracy causes an unexpected loss change due to fiber shift as a result of a plastic flow on the substrate surface in contact with the fibers.

We propose a mechanism to facilitate the development of component-based mobile applications with adaptive behaviors. The design principles and communication patterns of legacy software systems will greatly change in a forthcoming environment, where a variety of computing devices become embedded in home and office environments, users move around with/without portable computing devices, and all the devices are interconnected through wired/wireless networks. In the proposed mechanism, Improvised Assembly Mechanism (IAM), we realize functionality to compose an application in an ad hoc manner and to achieve the adaptation of applications by adding, replacing, supplementing, and relocating components at system runtime according to various environmental changes such as the locational changes of computing devices and users. The mechanism is implemented as a built-in functionality of the Soul component, which is one of the fundamental elements in the Possession model.

This paper describes two competitive learning algorithms from the viewpoint of deleting mechanisms of weight (reference) vectors. The techniques are termed the adaptivity and sensitivity deletions participated in the criteria of partition error and distortion error, respectively. Experimental results show the effectiveness of the proposed approaches in the average distortion.

Using LiTaO3 and LiNbO3 single crystals, we wish to miniaturize a powerful ultrasonic vibrator. We studied the method of measuring mechanical fractures of resonators with good reproducibility and collected data on mechanical fractures of crystals due to high input electric power. Chip resonators with a 4 MHz and 8 MHz shear mode were selected for the test samples. The driving frequency was swept near the resonance frequency, the duration time was short enough to raise the resonant vibrations and the driving voltage increased in one-volt increments. The method is free from unstable temperature increases. Values of the fracture limit for the driving current were measured and transformed to mechanical vibration velocities. These showed a nearly normal distribution. It was a surprise that concavity in the crater was observed at the center of the 16 MHz LiNbO3 resonator due to high input power. It was confirmed that the elastic fracture limit was latently very high for LiNbO3 and LiTaO3 single crystals.

In this paper we report on the modeling and simulation of tunneling current in MOS devices including quantum mechanical effects. The simulation model features an original scheme for the self-consistent solution of Poisson and Schrodinger equations and it is used for the extraction of the oxide thickness, by fitting CV curves, and the calculation of the tunneling current. Simulations and experiments are compared for different device types and oxide thicknesses (1.5-6.5 nm) showing good agreement and pointing out the importance of quantum mechanical modeling and the presence of many tunneling mechanisms in ultra-thin oxide MOS devices.

Thin films of carbon (C)-sulfur (S) compound were formed by plasma CVD (PCVD) at the special chemical condition. The reactor has a parallel plate electrode system and was operated at a discharge frequency of 13.56 MHz with using a mixture gas of argon (Ar), methane (CH4) and SF6. The deposition was performed on a substrate placed on the grounded electrode. Atomic composition of the film was observed to depend on the gas mixture ratio. The sulfur atom density was increased up to 30% with using a mixture gas at a pressure of 0.1 Torr and at a flow rate of 20, 20 and 50 SCCM for Ar, CH4 and SF6, respectively. It was expected that the C-S compounds were deposited under the condition of F atom elimination by forming HF.

An integrated slider-suspension system was designed and prototyped. The structure of this system has a full flying air-bearing surface in the leading part with a contamination-resistant feature, and it accommodates a slider with a 5-15 nm head-disk spacing at the trailing part. Performance analysis and simulation were conducted to validate the high performances of the design. Two key issues, the rigid motions (vibrations) and the elastic motions of the slider, were investigated systematically. For the rigid motions, it was found that the natural frequencies of the slider system are dependent on the disk contact stiffness and that the slider vibrations under excitation exhibit various nonlinear resonance. For the elastic motions, the average elastic response of the slider body under the random interaction of the interface was derived and characterized.

In this paper, we will present a study of the time-dependence effect in alumite perpendicular media at different thicknesses. Important parameters of the time-dependence effect such as magnetic viscosity and activation volume are investigated. Viscosity as a function of applied field (viscosity curve) exhibits a short plateau at a low field and then decreases monotonously with increasing field. After correcting for the demagnetizing field, the shape of the intrinsic viscosity curves changes to the well-known shape of the viscosity curve of in-plane media, i. e. , they have a peak near Hc. The intrinsic viscosity curves obtained from the experiments were fitted to an analytical model by Chantrell et al., from which, we found that the effective switching volumes obtained by fitting are much smaller than the column volumes, indicating that the reversal mechanism is incoherent.

We propose a new method to construct a four parameter family of quantum-mechanical point interactions in one dimension, which is known as all possible self-adjoint extensions of the symmetric operator T=-Δ C0(R \{0}). It is achieved in the small distance limit of equally spaced three neighboring Dirac's δ potentials. The strength for each δ is appropriately renormalized according to the distance and it diverges, in general, in the small distance limit. The validity of our method is ensured by numerical calculations. In general cases except for usual δ, the wave function discontinuity appears around the interaction and one can observe such a tendency even at a finite distance level.

This paper presents two competitive learning methods with the objective of avoiding the initial dependency of weight (reference) vectors. The first is termed the refractory and competitive learning algorithm. The algorithm has a refractory period: Once the cell has fired, a winner unit corresponding to the cell is not selected until a certain amount of time has passed. Thus, a specific unit does not become a winner in the early stage of processing. The second is termed the creative and competitive learning algorithm. The algorithm is presented as follows: First, only one output unit is prepared at the initial stage, and a weight vector according to the unit is updated under the competitive learning. Next, output units are created sequentially to a prespecified number based on the criterion of the partition error, and competitive learning is carried out until the ternimation condition is satisfied. Finally, we discuss algorithms which have little dependence on the initial values and compare them with the proposed algorithms. Experimental results are presented in order to show that the proposed methods are effective in the case of average distortion.

This paper proposes a new design method of nonlinear filtering and fixed-point smoothing algorithms in discrete-time stochastic systems. The observed value consists of nonlinearly modulated signal and additive white Gaussian observation noise. The filtering and fixed-point smoothing algorithms are designed based on the same idea as the extended Kalman filter derived based on the recursive least-squares Kalman filter in linear discrete-time stochastic systems. The proposed filter and fixed-point smoother necessitate the information of the autocovariance function of the signal, the variance of the observation noise, the nonlinear observation function and its differentiated one with respect to the signal. The estimation accuracy of the proposed extended filter is compared with the extended maximum a posteriori (MAP) filter theoretically. Also, the current estimators are compared in estimation accuracy with the extended MAP estimators, the extended Kalman estimators and the Kalman neuro computing method numerically.

We propose a learning algorithm for self-organizing neural networks to form a topology preserving map from an input manifold whose topology may dynamically change. Experimental results show that the network using the proposed algorithm can rapidly adjust itself to represent the topology of nonstationary input distributions.

With the progress of LSI technology, the electronic device size is presently scaling down to the nano-meter region. In such an ultrasmall device, it is indispensable to take quantum mechanical effects into account in device modeling. In this paper, we first review the approaches to the quantum mechanical modeling of carrier transport in ultrasmall semiconductor devices. Then, we propose a novel quantum device model based upon a direct solution of the Boltzmann equation for multi-dimensional practical use. In this model, the quantum effects are represented in terms of quantum mechanically corrected potential in the classical Boltzmann equation.

The ATM Forum specifies several fairness criteria, thus the scheduling mechanisms should allocate enough bandwidth to each connection to achieve one of such fairness criteria. However, two fairness criteria (MCR plus equal share, maximum of MCR or Max-Min share) cannot be achieved by conventional scheduling mechanisms. In this letter, we have developed new scheduling mechanisms that achieve these fairness criteria. We also present simulation results to show that our mechanisms can allocate bandwidth fairly.

In this paper we present a complete methodology for efficient electro-mechanical characterization of a CMOS compatible MEMS technology. Using an original test structure, the so-called "U-shape cantilever beam," we are able to determine all mechanical characteristics of force sensors constituted with elementary beams in a given technology. A complete set of electro-mechanical relations for the design of Microsystems have also been developed.

In this paper, we show that two-dimensional billiards with point interactions inside exhibit a chaotic nature in the microscopic world, although their classical counterpart is non-chaotic. After deriving the transition matrix of the system by using the self-adjoint extension theory of functional analysis, we deduce the general condition for the appearance of chaos. The prediction is confirmed by numerically examining the statistical properties of energy spectrum of rectangular billiards with multiple point interactions inside. The dependence of the level statistics on the strength as well as the number of the scatterers is displayed.

The Asynchronous Transfer Mode (ATM) technique has been accepted as a basis for the future B-ISDN networks. In ATM networks, all information is packetized and transferred in small packets of fixed length, called cells. The packetized information transfer, without flow control between the user and the network and the use of statistical multiplexing, results in a need of a policing mechanism to control the traffic parameters of each virtual connection in order to guarantee the required quality of service (QoS). Policing of the peak cell rate is generally not complex and can be achieved by using a cell spacer or other policing mechanisms (PMs). Monitoring of the mean cell rate is more difficult, but is intended to improve the link utilization when it has to handle bursty traffic sources. Conventional PMs, such as the Leaky Bucket Mechanism (LBM) and Window Mechanisms (WMs), are not well suited to the bursty nature of the sources supported by ATM networks, therefore intelligent PMs are needed. In this paper, we propose a Fuzzy Policing Mechanism (FPM) for multimedia applications over ATM networks. We consider the case of still picture source control. The performance evaluation via simulation shows that the FPM efficiently controls the mean cell rate of the still picture source. The proposed FPM shows a good response behavior against parameter variations and the selectivity characteristics approach very close to the ideal characteristic required for a PM. The FPM has a better characteristic compared with the LBM.