To investigate the feasibility of a compact FEA image sensor with a large number of pixels, a 128 96 pixel FEA image sensor with a 4-µm-thick HARP target was fabricated and tested for the first time. The experimental results showed that the prototype could stably operate as a highly sensitive image sensor having both sufficient resolution corresponding to the number of pixels and a wide dynamic range, which demonstrated its potential as a next-generation image sensor.

We propose a high-sensitivity and wide-dynamic-range position sensor using logarithmic-response and correlation circuit. The 3-D measurement system using the proposed position sensor has advantages to applications, for example a walking robot and a recognition system on vehicles, which require both of availability in various backgrounds and safe light projection for human eyes. The position sensor with a 64 64 pixel array has been developed and successfully tested. We describe the sensitivity of position detection as SBR (Signal-to-Background Ratio). The minimum SBR of the sensor is -13.9 dB lower than standard sensors. High sensitivity under -10 dB SBR is realized in a dynamic range of 41.7 dB in terms of background illumination. Experimental results of position detection and 3-D measurement in a strong background illumination are also presented.

This letter proposes a design methodology of a capacitor for a switched capacitor filter. The capacitor design method makes the capacitor accurate to the capacitance ratio and insensitive to the process deviation. The SCF designed is used for the PCM CODEC filter and the deviation of the frequency characteristic is below 0.05 dB for a process deviation 0.5 µm in 5 µm CMOS process.

We report our studies on the spectral sensitivity of superconducting NbN thin-film single-photon detectors (SPD's) capable of GHz counting rates of visible and near-infrared photons. In particular, it has been shown that a NbN SPD is sensitive to 1.55-µm wavelength radiation and can be used for quantum communication. Our SPD's exhibit experimentally measured intrinsic quantum efficiencies from 20% at 800 nm up to 1% at 1.55-µm wavelength. The devices demonstrate picosecond response time (<100 ps, limited by our readout system) and negligibly low dark counts. Spectral dependencies of photon counting of continuous-wave, 0.4-µm to 3.5-µm radiation, and 0.63-µm, 1.33-µm, and 1.55-µm laser-pulsed radiations are presented for the single-stripe-type and meander-type devices.

This paper proposes a measure of coefficient quantization errors for linear discrete-time state-space systems. The proposed measure of state-space systems agrees with the actual output error variance since it is derived from the exact evaluation of the output error variance due to coefficient deviation. The measure in this paper is represented by the controllability and the observability gramians and the state covariance matrix of the system. When the variance of coefficient variations is very small, the proposed measure is identical to the conventional statistical sensitivity of state-space systems. This paper also proposes a method of synthesizing minimum measure structures. Numerical examples show that the proposed measure is in very good agreement with the actual output error variance, and that minimum measure structures have a very small degradation of the frequency characteristic due to coefficient quantization.

This paper proposes a design method of variable IIR digital filters based on balanced realizations and minimum round-off noise realizations of digital filters. Highly accurate variable digital filters are easily derived by the proposed method. The coefficient matrices of both realizations of second-order digital filters are obtained directly from prototype realizations. The filter coefficients of variable digital filters can be obtained by frequency transformations to the realizations. The filter coefficients are presented as truncated Taylor series for the purpose of reducing a number of calculations to tune the coefficients. However the proposed filters have highly accurate variable characteristics against the coefficient truncation since balanced realizations and minimum round-off noise realizations have very low coefficient sensitivities, which are invariant under the frequency transformations. Moreover, the dynamic ranges of the proposed filters are almost constant against the frequency transformations. Numerical examples show the effectiveness of the variable digital filters designed by the proposed method.

In distributed network systems, it is one of the most important problems how to assign the files to servers in view of cost and delay. It is obvious that there is a trading-off relationship between costs and delays in these systems. In order to evaluate the optimization that the total cost is minimized subject to the total delay, we have presented the Optimal File Allocation Model as 0-1 integer programming, and have investigated the general characteristics in distributed systems. In this model, we have introduced many cost and delay parameters to evaluate the total cost and delay in the system more exactly. In constructing practical systems, it is necessary to investigate the weight and the contribution of each parameter to the total cost. It is very useful to show how to estimate cost and delay parameters on the basis of this analysis. In this paper, we analyze the sensitivity of these parameters and make clear the influence between principal parameters.

As the function of a system getting more complex, IP (Intellectual Property) reusing is the trend of system design style. Designers need to evaluate the performance and features of every candidate IP block that can be used in their design, while IP providers hope to keep the structure of their IP blocks a secret. An IP level power model is a model that takes only the primary input statistics as parameters and does not reveal any information about the sizes of the transistors or the structure of the circuit. This paper proposes a new method for constructing power model that is suitable for IP level circuit blocks. It is a nominal point selection method for power models based on power sensitivities. By analyzing the relationship between the dynamic power consumption of CMOS circuits and their input signal statistics, a guideline of selecting the nominal point is proposed. From our analysis, the first nominal point is selected to minimize the average estimation error and two other nominal points are selected to minimize the maximum estimation error. Our experimental results on a number of benchmark circuits show the effectiveness of the proposed method. Average estimation accuracy within 5.78% of transistor level simulations is achieved. The proposed method can be applied to build a system level power estimation environment without revealing the contents of the IP blocks inside. Thereby, it is a promising method for IP level power model construction.

We will discuss performance optimization of strain and temperature sensors based on long period fiber gratings (LPFGs) through control of the temperature sensitivity of the resonant peak shifts. Distinction between the effects of strain and temperature is a major concern for applications to communication and sensing. This was achieved in this work by suppressing or enhancing the temperature sensitivity by adjusting the doping concentrations of GeO2 and B2O3 in the core or cladding. The LPFGs were fabricated with a CO2 laser by the mechanical stress relaxation and microbending methods. The optimized temperature sensitivities were 0.002 nm/ for the suppressed case and 0.28 nm/ for the enhanced case, respectively. These LPFGs were used for simultaneous measurement of strain and temperature. The result indicates the rms errors of 23 µstrain for the strain and 1.3 for the temperature.

One of the most important capacity parameters in the DS-CDMA cellular systems is the system reliability on which the reverse link capacity is usually limited by a prescribed lower bound. In this letter, the effect of the system reliability as well as imperfection of the power control on the system capacity is quantitatively considered using sensitivity analysis in a multimedia DS-CDMA cellular system. As a result, an analytical close-form formula is presented in terms of the standard deviation of the received SIR and the system reliability. In a numerical example, sensitivity with respect to the system reliability on the system capacity has the value ranging from 5 to 50 between 95% and 99% the range in we are interested.

A fiber Bragg grating, which has periodical perturbation of the refractive index in the fiber core, acts as a wavelength selective reflection filter and steep optical spectrum can be realized by forming more than ten thousand of gratings along the fiber core. Owing to capability of making steep optical spectrum, fiber Bragg gratings has been expected to be introduced practical use as multiplexing or demultiplexing filters in dense WDM transmission systems. On the other hand, radiation mode loss, reflection side mode and temperature dependence of Bragg wavelength, should be improved to put the fiber Bragg grating to practical use in dense WDM transmission systems. In this paper, an optimum design and performance of the fiber Bragg grating for dense WDM systems are described. The photosensitive cladding fiber realized less than 0. 2 dB insertion loss at transmitted signal channels and less than 0. 1 dB splicing loss with standard single-mode fibers. An adequate apodization technique in the refractive index distribution suppressed reflection side modes. A temperature compensating package, which gives longitudinal strain with negative temperature dependence to a fiber Bragg grating, minimized temperature dependence of Bragg wavelength less than 0. 001 nm/. Thermal decay of Bragg grating was also investigated and adequate annealing condition was estimated to obtain sufficient stability for practical use in dense WDM transmission.

We fabricated a tunable and polarization-insensitive arrayed-waveguide grating (AWG) 1616 multiplexer that operates around the wavelength of 1. 55 µm using fluorinated polyimides. The wavelength channel spacing was 0. 8 nm, and the 3-dB passband width was 0. 26 nm. The insertion loss at each channel was from 8 to 12 dB, and the crosstalk was less than -28 dB. The transmission pass wavelength was tuned over a wide range of 6 nm by heating from 24 to 64. The slope of the temperature dependence of the pass wavelength was -0. 15 nm/, which is ten times that of a silica-based multiplexer. Polarization-insensitivity was achieved by fabricating a film AWG multiplexer, which was formed by removing the silicon substrate and annealing at 350. The polarization-dependent wavelength shift was smaller than the spectrum analyzers wavelength resolution of 0. 1 nm.

In this paper, two universal building blocks for complex filter using CCIIs, CFCCIIs, grounded resistors and grounded capacitors are presented. These can be used to realize various complex bandpass filters with arbitrary order. The paper shows that the response error of the proposed circuit caused by nonideality of active components is more easily compensated than that of the conventional one employing op-amps, and that the sensitivities for all components are relatively small. Experimental results are used for verifying the validity of the proposed circuits.

The problem of restoring binary (black and white) images degraded by color-dependent flip-flap noises is considered. The real image is modeled by a Markov Random Field (MRF). The Iterated Conditional Modes (ICM) algorithm is adopted. It is shown that under certain conditions the ICM algorithm is insensitive to the MRF image model and noise parameters. Using this property, we propose a parameter-free restoration algorithm which does not require the estimations of the image model and noise parameters and thus can be implemented fully in parallel. The effectiveness of the proposed algorithm is shown through applying the algorithm to degraded hand-drawn and synthetic images.

The characteristics of high-performance InP-based monolithically integrated single and multiple channel photoreceivers with an InGaAs p-i-n photodiode and InAlAs/InGaAs HBTs, realized by one-step molecular beam epitaxy, are described. The monolithically integrated photoreceiver includes an integrated spiral inductor following the p-i-n diode at the input of the transimpedance amplifier to enhance the circuit response at high frequencies. Crosstalk of the multi-channel photoreceiver arrays is greatly reduced by applying both a metal ground shield and dual bias. The maximum measured -3 dB bandwidth of a single-channel integrated p-i-n/HBT photoreceiver is 19.5 GHz and the minimum crosstalk of the photoreceiver arrays, with an individual channel bandwidth of 11.5 GHz, is 36 dB. At these performance levels, these OEICs represent the state-of-the-art in multichannel integrated photoreceiver arrays.

Polarization insensitive discrete electroabsorption modulators have been designed as an optical gating device. It reveals the first finding, to our knowledge, that the ratio of the optical confinement factor (Γ) to the differential of the values (ΔΓ) between TE and TM polarized lights decides polarization dependence of attenuation. The ratio ΔΓ/Γ is significantly reduced by increasing core thickness. Large optical confinement structures combining a thick InGaAsP bulk absorption layer and polyimide-buried mesa-ridge waveguide have fabricated. The ratio ΔΓ/Γ of the high-mesa structure was estimated to be less than 0.05 in the gain-region of an erbium-doped fiber amplifier (EDFA), which enable us extremely low polarization sensitivity less than 1 dB up to 20 dB extinction. Proper waveguide length of the structure allowed low insertion loss ( 9.3 dB), small loss-change ( 1.8 dB) and sufficient modulation depth ( 30 dB) simultaneously in the EDFA's gain region. The low-mesa structure provided low insertion loss around 7 dB with small deviation in the wavelength region. High modulation band-width and a polarization-insensitive optical gating waveform have also demonstrated.

Video services such as video-on-demand are expected to be a motivation for deploying multimedia services in residential areas. These services should increase customer demand for video channels as customer demands become more sophisticated and diverse in the future. Therefore, it is important to determine how network configurations (i.e. network transition scenarios) should evolve in response to changes in access network demand. This paper proposes economical deployment of access networks based on transition scenarios. We conclude that transition scenarios offer more economical deployment than single-network configurations. Two transition scenarios, from passive double-star to fiber single-star, and from hybrid fiber-coax to fiber single-star, are evaluated as examples. These transition scenarios are economical even when customer demand changes. The transition starting time affects the present worth of annual charges (PWAC) of access networks more than the transition period does.

This paper is described on the realization of simulated inductance cercuit with parallel negative conductance and its application for an oscillator. The design's condition for realizing the circuit needs stability, narrow expance of elements, larger dynamic-range and lower sensitivity. A new floating simulated inductance circuit with parallel nagative conductance with two operational amplifiers, four resistors, and four capacitors is created by using the design's algorithm. And the elements sensitivity of the simulated circuit is superior to that of the conventional circuits. By experimenting with a resonance circuit, the author tested the sinusoidal oscillator's circuit of a parallel -GLC as an application in order to confirm the operation of the simulated inductance circuit with parallel negative conductance.

This article considers a hybrid data backup model for a file system, which combines both conventional magnetic disk (MD) and write-once, read-many optical disk (OD). Since OD recently is a lower cost medium as well as a longer life medium than the ordinary MD, this kind of backup configuration is just recognized to be important. We mathematically formulate the hybrid data backup model and obtain the closed-form average cost rate when the system failure time and the recovery time follow exponential distributions. Numerical calculations are carried out to obtain the optimal backup policy, which is composed of two kinds of backup sizes from the main memory to MD and from MD to OD and minimizes the average cost rate. In numerical examples, the dependence of the optimal backup policy on the failure and the recovery mechanism is examined.

The disturbance-rejection problem is to find a feedback control law for linear control systems such that the influence of disturbances is completely rejected from the output. In 1970 Wonham and Morse first studied this problem in the framework of the so-called geometric approach. On the other hand, in 1985 Ghosh studied parameter insensitive disturbance-rejection problems with state feedback and with dynamic compensator. In this paper we study the parameter insensitive disturbance-rejection problem with static incomplete-state feedback for linear multivariable systems in the framework of the geometric approach from the mathematical point of view. Necessary conditions and/or sufficient conditions for this problem to be solvable are presented. Finally an illustrative example is presented.