We studied effects of 50-200-keV electrons on semiconductor devices using BEASTLI (backscattered electron assisting LSI inspection) method. When irradiating semiconduc-tor devices with such high-energy electrons, we have to note two phenomena. The first is surface charging and the second is device damage. In our study of surface charging, we found that a net positive charge was formed on the device surface. The positive surface charges do not cause serious influence for observation so that we can inspect wafers without problems. The positive surface charging may be brought about because most incident electrons penetrate the device layer and reach the conducting substrate of the semiconductor device. For the device damage, we studied MOS devices which were sensitive to electron-beam irradiation. By applying a 400- annealing to electron-beam irradiated MOS devices, we could restore the initial characteris-tics of MOS devices. However, in order to recover hot-carrier degradation due to neutral traps, we had to apply a 900- annealing to the electron-beam irradiated MOS devices. Thus, BEASTLI could be successfully used by providing an apporopri-ate annealing to the electron-beam irradiated MOS devices.

A new electron-beam wafer inspection system has been developed. The system has a resolution of 5 nm or better, and is applicable to quarter-micron devices such as 256 Mbit DRAMs. The most remarkable feature of this system is that a specimen stage is built in the objective lens and allows a working distance (WD) of 0. "WD=0"minimizes the effect of lens aberrations, and maximizes the resolving power. Innovative designs to achieve WD=0 are as follows: (1)A large objective lens of 730-mm width 730-mm depth 620-mm height that serves as a specimen chamber, has been developed. (2)A hollow specimen stage made of non-magnetic materials has been developed.It allows the lower pole piece and magnetic coile of the objective lens inside it. (3)Acoustic motors made of non-magnetic materials are em-ployed for use in vacuum.

Understanding unknown objects in images is one of the most important fields of the computer vision. We are confronted with the problem of dealing with the ambiguity of the image information about unknown objects in the scene. The purpose of this paper is to propose a new object recognition method based on the fuzzy relation system and the fuzzy integral. In order to deal with the ambiguity of the image information, we apply the fuzzy theory to object recognition subjects. Firstly, we define the degree of similarity based on the fuzzy relation system among input images and object models. In the next, to avoid the uncertainty of relations between the input image and the 2-D aspects of models, we integrate the degree of similarity obtained from several input images by the fuzzy integral. This proposing method makes it possible to recognize the unknown objects correctly under the ambiguity of the image information. And the validity of our method is confirmed by the experiments with six kinds of chairs.

This paper describes a study to determine if a current-mode circuit is useful as an analog circuit technique for realizing submicron mixed analog-and-digital MOS LSIs. To examine this, we designed and circuit simulated a new current-mode ADC bit-block for a 3 V, 10-bit level, 20 MHz ADC with a pipeline architecture and with full current-mode approach. A new precision current-mode sample-and-hold circuit which enables operation of a bit block at a clock speed of 20 MHz was developed. Current mismatches caused by the poor output impedance of a device were also decreased by adopting a cascode configuration throughout the design. Operation with a 3 V power supply and a 20 MHz clock speed in a 3-bit A/D configuration was verified through circuit simulation using standard CMOS 0.6 µm device parameters. Gain error, mismatch of current, and linearity of the bit block with changing threshold voltage of a device were carefully examined. The bit block has a gain error of 0.2% (10-bit level), a linearity error of less than 0.1% (more than 10-bit level), and a current mismatch of DAC current sources in a bit cell of 0.2 to 0.4% (more than 8-bit level) with a 3 V power supply and 20 MHz clock speed. An 8-to 9-bit video-speed pipeline ADC can be realized without calibration. This confirms that the current-mode approach is effective.

The message level performance of error controls in data communication on ATM network is analyzed. Three layers, "a cell"(a unit of transmission), "a block"(a unit of error controls) and "a message"(a unit of transmission of user level) are considered. The error controls treated in this paper are GBN (Go-Back-N) and FEC+GBN. The cell loss process is assumed to be the two state Markov chain considering the cell loss process in ATM networks. Numerical results show that (1) the improvement of the message forwarding delay is saturated in some environments when the interface rate becomes high, (2) FEC is efficient when the burstiness of the cell loss process is small, the message length is large and the interface rate is high.

A trained sparse conjugate codebook is proposed for improving the speech quality of CELP-based coding in a noisy environment. Although CELP coding provides high quality at a low bit rate in a silent environment (creating clean speech), it cannot provide a satisfactory quality in a noisy environment because the conventional fixed codebook is designed to be suitable for clean speech. The proposed codebook consists of two sub-codebooks; each sub-codebook consists of a random component and a trained component. Each component has excitation vectors consisting of a few pulses. In the random component, pulse position and amplitude are determined randomly. Since the radom component does not depend on the speech characteristics, it handles noise better than the trained one. The trained component maintains high quality for clean speech. Since excitation vector is the sum of the two sub-excitation vectors, this codebook handles various speech conditions by selecting a sub-vector from each component. This codebook also reduces the computational complexity of a fixed codebook search and memory requirements compared with the conventional codebook. Subjective testing (absolute category rating (ACR) and degradation category rating (DCR)) indicated that this codebook improves speech quality compared with the conventional trained codebook for noisy speech. The ACR test showed that the quality of the 8 kbit/s CELP coder with this codebook is equivalent to that of the 32 kbit/s ADPCM for clean speech.

In this paper, we propose to use graded-index multimode fibers (GI-MMFs) with Fabry-Perot laser diodes (FP-LDs) for short-span and low-cost feeders. The multimode fiber feeders can be applied to wireless personal communication systems where the required feeder length is within several hundred meters, such as distributed antenna networks for microcellular systems or wireless LANs. The use of multimode fibers makes fiber coupling and connection easier, and has the potential to greatly reduce total system cost. Three types of GI-MMFs are considered as transmission media, (1) silica-based glass optical fiber (GI-GOF),(2) silica-core plastic-clad fiber (GI-PCF), and (3) all-plastic optical fiber (GI-POF). It is shown that GI-GOF and GI-PCF are suitable for use as feeders in the microcells of CDMA cellular and wireless LAN systems within 300m in length. GI-POF is estimated to be suitable for use as feeders in wireless LANs within 100m in length. A multimode fiber feeder with FP-LDs and GI-PCF of 300 m is developed in order to demonstrate its applicability to a wireless LAN system operating in the 2.4 GHz ISM band.

The SAR distributions over a homogeneous human model exposed to a near field of a short electric dipole in the resonant frequency region were calculated with the spatial resolution of 1cm3 which approximated 1g tissue by using the FDTD method with the expansion technique. The dependences of the SAR distribution on the distance between the model and the source and on frequency were investigated. It was shown that the large local SAR appeared in the parts of the body nearest to the source when the source was located at 20cm from the body, whereas the local SAR were largest in the narrow sections such as the neck and legs when the source was farther than 80cm from the model. It was also shown that, for the near-field exposure in the resonant frequency region, the profile of the layer averaged SAR distribution along the main axis of the body of the human model depended little on frequency, and that the SAR distribution in the section perpendicular to the main axis of the human body depended on frequency. The maximum local SAR per gram tissue over the whole body model was also determined, showing that the ratios of the maximum local SAR to the whole-body averaged SAR for the near-field exposure were at most several times as large as the corresponding ratio for the far-field exposure, when the small source located farther than 20cm from the surface of the human model.

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.

This paper discusses a software verification support environment Vega which is based on a model-theoretic methodology that enables verification support for the temporal properties of protocol specifications described in the formal description technique LOTOS. In the methodology of Vega, a protocol specification is defined through the LOTOS process reflecting its practical system structure. The temporal properties to be verified are given as the requirement which the protocol needs to satisfy from the viewpoint of events and are formulated by using the branching time temporal logic defined in this paper. Verification is done by determining whether or not the given temporal properties are satisfied by the model, which corresponds to the transition system derived from the LOTOS specification of the protocol. Vega is provided with an effective interface function, as well as the function of simple model checking based on the above methodology, to give some degree of flexibility for the expression of temporal properties to be verified. Specifically, it allows the user to define useful expressions by combining builtin temporal logic formulas and enter them in Vega for use at any time. With the provision of these functions, Vega is expected to serve as a very powerful and flexible verification support tool.

A new approach is presented for recovering the 3-D shape from shading image. Photometric Stereo Method (PSM) is generally based on the direct illumination. PSM in this paper is modified with the indirect diffuse illumination method (IDIM), and then applied to hybrid reflectance model which consists of two components; the Lambertian reflectance and the specular reflectance. Under the hybrid reflectance model and the indirect diffuse illumination circumstances, the 3-D shape of objects can be recovered from the surface normal vector extracted from the surface roughness, the surface reflectance ratio, and the intensity value of a pixel. This method is rapid because of using the reference table, simplifies the restriction condition about the reflectance function in prior studies without any loss in performance, and can be applied to various types of surfaces by defining general reflectance function.

This paper describes ALINX (Advanced Low-voltage Interface Circuit System), a low-power and high-speed interface circuit of submicron CMOS LSI for digital information and telecommunications systems. Differential and single-ended ALINXs are low-voltage swing I/O interface circuits with less than 1.0 V swing from a 1.2 V supply. Specifically, the differential ALINX features a pair of complementary NMOS push-pull drivers operating from a 1.2 V supply, reducing power consumption compared to conventional high-speed interface circuits operating from a 5 V or 3.3 V supply. The DC power consumption is approximately 11% of ECL. We observed 622 Mbps differential transmission with 8 mW power consumption and single-ended transmission at 311 Mbps with 14 mW with a PN23 pseudo-random pattern. We also describe a noise characteristic and ALINX applications to high-speed data buses and LSI for telecommunications systems. A time/space switch LSI with 0.9 W total power consumption was fabricated by 0.5 µm CMOS process technology. This chip can use a plastic QFP.

A new method is proposed for realizing a flexible change detection which is free from the limitation that multitemporal images must have the same spectral bands whose center wavelength and bandwidth are identical. As spaceborne multispectral scanners are continuously improved for performance and new scanners do not necessarily have the same spaectral bands for observation, this limitation is a serious obstacle for detecting long term temporal change. The proposed method removes this limitation by using an image normalization technique based on multiple regression analysis. The method is successfully applied to actual remotely sensed multitemporal images.

Data reduction method for the earth-satellite-earth laser long-path absorption measurements of atmospheric trace species using the Retroreflector in Space (RIS) on the Advanced Earth Observing Satellite (ADEOS) is described. In the RIS experiment, atmospheric absorption will be measured with single-longitudinal-mode pulsed CO2 lasers and their second and third harmonics. High-resolution absorption spectra are measured by using the Doppler shift of the return beam which is caused by the satellite movement. Vertical profiles of O3 and CH4 are retrieved from the measured absorption line shapes with the inversion method. Also, column contents of CFC12, HNO3, CO2, CO, N2O are derived by the least squares method with assumptions on the relative vertical profiles. Errors in the measurement were evaluated by computer simulation.

A new low-power and high-speed CMOS interface circuit is proposed in which signals are transmitted by means of impulse voltage. This mode of transmission is called impulse transmission. Although a termination resistor is used for impedance matching, the current through the output transistors and the termination resistor flows only in transient states and no current flows in stable states. The output buffer and the termination resistor dissipate power only in transient states, so their power dissipation is reduced to 30% that of conventional low-voltage-swing CMOS interface circuits at 160 MHz. The circuit was fabricated by 0.5 µm CMOS technology and was evaluated at a supply voltage of 3.3 V. Experimental results confirm low power of 4.8 mW at 160 MHz and high-speed 870 Mb/s error free point-to-point transmission.

A non-invasive method is proposed to estimate the location of intracranial vascular disease using several sensors placed on the forehead. The advantage of this method over earlier measurements with a single ocular sensor is the abilty to localize the region of abnormal vascular tissue. A weighted least mean square procedure is applied to estimating the time difference between the sensor outputs using the phase distribution in the cross-spectrum. It is possible to estimate time differences shorter than sampling period. Computer simulation and clinical experiments demonstrate that a distance difference of around 20 times shorter than the wavelength can be obtained.

A new high performance digital signal processor (DSP) that lowers power consumption, reduces chip count, and enables system cost savings for wireless communications applications was developed. The new device contains high performance, hard-wired functionality with a specialized instruction set to effectively implement the worldwide digital cellular standard algorithms, including GSM, PDC and NADC, and also features both full rate and future half rate processing by software modules. The device provides a wider operating voltage ranging from 1.5 V to 5.5 V using 5 V process based on the market requirement of 5 V supply voltage, even though a power supply voltage in most applications will be shifted to 3 V. Several circuits was newly developed to achieve low power consumption and high speed operation at both 5 V and 3 V process using the same data base. The device also features over 50 MIPS of processing power with low power consumption and 100 nA stand-by current at either 3 V or 5 V. One remarkable advantage is a flexible CPU core approach for the future spin-off devices with different ROM/RAM configurations and peripheral modules without requiring any CPU design changes. This paper describes the architecture of a lower power and high speed design with effective hardware and software modules implementations.

In this study, an extraction method of failure sound signal which is strongly contaminated by noise is investigated by genetic algorithm and statistical tests of the frequency domain for the failure diagnosis of machinery. In order to check the extraction accuracy of the failure signal and obtain the optimum extraction of failure signal, the "existing probability Ps (t*k) of failure signal" and statistical information Iqp are defined as the standard indices for evaluation of the extraction results. It has been proven by practical field data and application of the inspection and diagnosis robot that the extraction method discussed in this paper is effective for detection of a failure and distinction of it's origin in the diagnosis of machinery.