Aczel's theory of structured objects is extended under the assumption that a structured object may belong to a sort and that these sorts are partially ordered. Based on the assumption, the forms of required objects can be specified more precisely and concisely. The resulting theory provides a general principle for the construction of order-sorted ontologies and universes of structured objects. It is applicable to systems with structured objects, such as situation theory, feature-based grammars, knowledge representation, constraint logic programming and object-oriented systems.

This paper proposes a topology-independent predistortion for filters using integrators. This employs integrators having the same structure, the same-value elements and an electrically controllable unity-gain frequency and compensates for the deviation of frequency characteristics due to excess phase shifts of integrators without knowledge of a filter topology. The effectiveness of the proposed method is demonstrated through SPICE simulations.

This letter describes an efficient and economical method for dropping optical fiber to residential premises in which several fiber ribbons in a distribution cable are assigned to one dropping point. The optical fiber cables for dropping, which contain mono-coated fibers, are then aerially installed between several poles from this point during initial construction. One or two fibers in a cable are then branched and dropped to a subscriber when the demand arises. When an optical drop wire stranded cable is used as the optical fiber cable for dropping, the above method can be employed without the need for a fiber joint in the dropping portion. The tube stranding pitch of this cable is investigated theoretically and experimentally, and the cable is manufactured based on the results. The transmission characteristics of the cable are confirmed to be stable.

This paper describes the new analog-digital merged circuit architecture which utilizes the pulse modulation signals. By reconsidering the information representing and processing principles, and the circuit operations governed by the physical law, the new circuit architecture is proposed to overcome the limitations of existent VLSI technologies. The proposed architecture utilizes the pulse width modulation (PWM) signal which has analog information in the time domain, and be constructed with the novel PWM circuits which carry out the multi-input arithmetic operations, the signal conversions and the data storage. It has a potential to exploit the high speed switching capability of deep sub-µm devices, and to reduce the number of devices and the power dissipation to one-tenth of those of the binary digital circuits. Therefore it will effectively implement the intelligent processing systems utilizing 0.5-0.2µm scaled CMOS devices.

The electrical characteristics of sealed CMOSFETs with gates crossing sources/drains at 90 and 45 are experimentally investigated using test devices fabricated by an n-well CMOS process with trench isolation. Gain factors of surface-channel 90 and 45 n-MOSFETs can be estimated by a simple correction theory based on the combination of a center MOSFET and two edge MOSFETs. However, relatively large departures from the theory are observed in buried-channel 90 and 45 p-MOSFETs with widths less than the channel length. The difference between n- and p-MOSFETs is mainly due to the channel type. Other basic device parameters such as saturation drain currents, threshold voltages, subthreshold swings, maximum substrate currents and substrate-voltage dependence of threshold voltages are also measured and qualitatively explained.

This letter presents a new design method for approximate inverse systems using all-pass networks. The efficacy of approximate inverse systems for input and parameter estimation of nonminimum phase systems is well recognized. in the previous methods, only time domain design of FIR (finite impulse response) type approximate inverse systems were considered. Here, we demonstrate that IIR (infinite impulse response) type approximate inverse systems outperform the previous methods. A nonlinear optimization technique is adopted for designing the proposed system in the frequency domain. Numerical examples are also presented to show the effectiveness of the proposed method.

This letter shows that a portable visual stimulator for MEG measurements can be realized using an optical fiber bundle and a CRT display system offering high brightness and high speed raster scanning, and that MEGs with neither magnetic contamination nor jitter can be measured by the stimulator.

The degradation of I-V characteristics under constant emitter-base reverse voltage stress in advanced self-aligned bipolar transistors was analyzed. Experimental analyses have been taken the stress field effect into account when predicting hot-carrier degradation. These analyses showed that base current starts to increase when the reverse voltage stress is about 3 V. The dependence of the base current change on reverse voltages of more than 3 V was also investigated experimentally, and equations expressing hot-carrier degradation in terms of the exponential dependence of excess base current on both reverse stress voltage and stress-enhancing voltage related to emitter-base breakdown voltage were derived.

According as the fine LSI process technique develops, the technique to reduce power dissipation of high-frequency integrated analog circuits is getting more important. This paper describes a design of high-frequency integrator with low power dissipation for monolithic leapfrog filters. In the design of the conventional monolithic integrators, there has been a great dfficulty that a high-frequency integrator which can operate at low supply voltage cannot be realized without additional circuits, such as unbalanced-to-balanced conversion circuits and common-mode feedback circuits. The proposed integrator is based on the Miller integrator. By a PNP current mirror circuit, high CMRR is realized. However, the high-frequency characteristic of the integrator is independent of PNP transistors. In addition, it can operate at low supply voltage. The excess phase shift of the integrator is compensated by insertion of the compensation capacitance. The effectiveness of the proposed technique is confirmed by PSPICE simulation. The simulation results of the integrator shows that the common-mode gain is efficiently low and the virtual ground is realized, and that moderate phase compensation can be achieved. The simulation results of the 3rd-order leapfrog filter using the integrator shows that the 50 MHz-cutoff frequency filter is obtained. Its power dissipation in operating 2 V-supply voltage is 5.22 mW.

A novel technique for evaluation of charge build-up in semiconductor wafer processing such as ion implantation, plasma etching and plasma enhanced chemical vapor deposition by using the breakdown of MOS capacitors with charge collecting electrodes (antenna) is proposed. The charge build-up during high beam current ion implantation is successfully evaluated by using this technique. The breakdown sensitivity of a MOS capacitor is improved by using a small area MOS capacitor with a large area antenna electrode. To estimate charge build-up on wafers quantitatively, the best combination of gate oxide thickness, substrate type, MOS capacitor area and antenna ratio should be carefully chosen for individual charge build-up situation. The optimum structured antenna MOS capacitors which relationship between QBD and stressing current density was well characterized give us very simple and quantitative charge build-up evaluation. This technique is very simple and useful to estimate charge build-up as compared with conventional technique by suing EEPROM devices or large area MOS capacitors.

The properties of the optical-microwave mixing process are investigated in detail. To describe these processes a new approach, the parametric method is introduced which provides a better description of the mixing phenomenon. The paper presents new experimental results on and new theoretical analysis methods for the optical-microwave mixing process and also for its dynamic behavior. The dynamic properties are very important in many applications when the light is intensity modulated by a high frequency or high bit rate signal. A remarkable decrease is observed in the mixing product with increasing optical modulation frequency. There are two reasons for it: the time constant exhibited by the depletion region between the substrate and the epitaxial layer and the optically induced substrate current which is increasing with the modulation frequency and doesn't contribute to the mixing effect. Understanding the optical-microwave mixing process provides new solutions for many applications. For example the optical-microwave mixing techniques offers several advantages in case of optical reception. In the detection process the modulation signal can be transposed to an intermediate frequency band (instead of the baseband) making possible a lower noise reception in a wider band. Another important and advantageous application is in the reception of subcarrier modulated optical signals.

Access control has been an important security issue in information systems. Multilevel hierarchical information access widely exists in present-day government, military, and business applications. Extending access control design to work in a hierarchical environment is natural and necessary but rarely addressed so far in the literature. In this paper, a dynamic group-oriented cryptographic scheme to access a multilevel data hierarchy is proposed. In the proposed scheme, a trusted central authority is in charge of the administrative activities among the organization hierarchy. At the beginning, each user class submits its associated information and a cryptographic key of its preference to the central authority. Next the central authority generates a public information for each class according to their location in the organization hierarchy. The cryptographic key held by each class can be used directly as an encryption key to encipher data. These keys need not be modified when adding/deleting a class to/from the system. Compare with other existing schemes, ours has the advantages of flexibility in choosing user preferred cryptographic keys, cryptographic keys not exceeding a fixed length, reduced storage space in publishing pubic information, and protection from conspiracy attack.

We present a recursive algorithm for constructing linear discrete-time systems which interpolate the desired 1st-and 2nd-order information. The recursive algorithm constructs a new system and connects it to the previous system in the cascade form every time new information is added. These procedures yield a practical realization of all the interpolants.

An optoelectronic beam forming network (BFN) is presented for a single beam, 3-element phased array antenna that utilizes electrically controllable birefringence mode nematic liquid-crystal cells (ECB mode NLC cells) for phase shifting and amplitude control. In the circuit, a microwave signal is carried by a pair of orthogonal linearly polarized lightwaves (signal and reference lightwaves) using the optical heterodyning technique. Birefringence of liquid-crystals is utilized to selectively control the phase of the signal and reference lightwaves. Because an interferometer is formed on a single signal path, the complexity of the optical circuit is much reduced, compared to the BFNs based on arrays of Mach-Zender interferometers. A prototype circuit is built using laser sources of 1.3 µm, and its performance experimentally examined. With small deviations among the three cells, phase shifts of up to 240 degrees are achived for MW signals from 0.9 GHz to 20 GHz with good stability; attenuation of more than 18dB is achieved. An optoelectronic technique for parallel control of amplitude and phase of MW signals was developed.

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.

This paper proposes a photonic integrated beam forming and steering network (BFN) that uses switched true-time-delay (TTD) silica-based waveguide circuits for phased array antennas. The TTD-BFN has thermooptic switches and variable time delay lines. This TTD-BFN controls four array elements, and can form and steer a beam. An RF test was carried out in the 2.5 GHz microwave frequency range. The experimental results show a peak-to-peak phase error of 6.0 degrees and peak-to-peak amplitude error of 2.0 dB. Array factors obtained from the measured results agree well with the designed ones. This silica-based beam former will be a key element in phased array antennas.

In this paper, we propose a new method of dialogue data collection which can be used to evaluate modules of a spoken dialogue system. To evaluate the module, it is necessary to use suitable data. Human-human dialogue data have not been appropriate to module evaluation, because spontaneous data usually include too much specific phenomena such as fillers, restarts, pauses, and hesitations. Human-machine dialogue data have not been appropriate to module evaluation, because the dialogue was unnatural and the available vocabularies were limited. Here, we propose 'Hybrid method' for the collection of spoken dialogue data. The merit is that, the collected data can be used as test data for the evaluation of a spoken dialogue system without any modification. In our method a human takes the role of some modules of the system and the system, also, works as the other part of the system together. For example, humans works as the speech recognition module and the dialogue management and a machine does the other part, response generation module. The collected data are good for the evaluation of the speech recognition and the dialogue management modules. The reasons are as follows. (1) Lexicon: The lexicon was composed of limited words and dependent on the task. (2) Grammar: The intention expressed by the subjects were concise and clear. (3) Topics: There were few utterances outside the task domain. The collected data can be used test data for the evaluation of a spoken dialogue system without any modification.

Caenorhabditis elegans during feeding gives good moving biological images",in which motions of several pulsing organs are superposed on its head swing. A powerful method to extract dynamic features is presented. First step is to use a variance picture VAG4 in order to pick up active pixel coordinates of concerned moving objects. Superiority of VAG4 over usual variance picture VAG2 is shown quantitatively by a model of moving particles. Pulsing areas of C. elegans, are exhibited more clearly in VAG4 than VAG2. Second step is use of a new subtraction method to extract main frequency bands. FFT spectra are averaged in active positions where VAG4 is above threshold THVR in the square with 88 pixels (ONA). The power spectra averaged in the enlarged squares (ELA) are subtracted from those in ONA, in which ELA includes ONA in its centre position. Large peak bands emerge in the subtracted power spectra. The subtraction eliminates the effect of head swing by spatial averagings in ELA. This new emphasizing method is compared to another subtraction method. The characteristic frequency of periodical moving organs coincides well with the values observed by other research groups and our visual estimation of replayed VTR images. Thus the proposed extraction method is verified to work well in double superposed motions.

This paper proposes a Japanese continuous speech recognition mechanism in which a full-sentence-level context-free-grammar (CFG) and one kind of semantic constraint called dependency relationships between two bunsetsu (a kind of phrase) in Japanese" are used during speech recognition in an integrated way. Each dependency relationship is a modification relationship between two bunsetsu; these relationships include the case-frame relationship of a noun bunsetsu to a predicate bunsetsu, or adnominal modification relationships such as a noun bunsetsu to a noun bunsetsu. To suppress the processing overhead caused by using relationships of this type during speech recognition, no rigorous semantic analysis is performed. Instead, a simple matching with examples" approach is adopted. An experiment was carried out and results were compared with a case employing only CFG constraints. They show that the speech recognition accuracy is improved and that the overhead is small enough.

This paper presents the performance prediction method on sentence recognition system which uses a finite state word automaton. When each word is uttered separately, the relationship between word recognition score and sentence recognition score can be approximated using the number of word sequences at a minimum distance from each sentence in the task. But it is not clear that how we get this number when the finite state word automaton is used as linguistic information. Therefore, we propose the algorithm to calculate this number in polynomial time. Then we carry out the prediction using this method and the simulation to compare with the prediction on the task of Japanese text editor commands. And it is shown that our method approximates the lower limit of sentence recognition score.