This paper presents methods for detecting transistor short faults using logic level fault simulation and test generation. The paper considers two types of transistor level faults, namely strong shorts and weak shorts, which were introduced in our previous research. These faults are defined based on the values of outputs of faulty gates. The proposed fault simulation and test generation are performed using gate-level tools designed to deal with stuck-at faults, and no transistor-level tools are required. In the test generation process, a circuit is modified by inserting inverters, and a stuck-at test generator is used. The modification of a circuit does not mean a design-for-testability technique, as the modified circuit is used only during the test generation process. Further, generated test patterns are compacted by fault simulation. Also, since the weak short model involves uncertainty in its behavior, we define fault coverage and fault efficiency in three different way, namely, optimistic, pessimistic and probabilistic and assess them. Finally, experimental results for ISCAS benchmark circuits are used to demonstrate the effectiveness of the proposed methods.

A radio-on-dense-wavelength-division-multiplexing (DWDM) transport system based on injection-locked Fabry-Perot laser diodes (FP LDs) with four microwave carriers and large effective area fiber (LEAF) transmission was proposed and demonstrated. Good performance of bit error rate (BER) and intermodulation distortion to carrier ratio (IMD/C) over a-50 km of LEAF was obtained. Signal quality meets the demands of personal handy system (PHS)/vehicle information and communication system (VICS)/electronic toll collection (ETC)/satellite broadcasting (SB).

We developed an Nb-based fabrication process for single flux quantum (SFQ) circuits in a Japanese government project that began in September 2002 and ended in March 2007. Our conventional process, called the Standard Process (SDP), was improved by overhauling all the process steps and routine process checks for all wafers. Wafer yield with the improved SDP dramatically increased from 50% to over 90%. We also developed a new fabrication process for SFQ circuits, called the Advanced Process (ADP). The specifications for ADP are nine planarized Nb layers, a minimum Josephson junction (JJ) size of 11 µm, a line width of 0.8 µm, a JJ critical current density of 10 kA/cm2, a 2.4 Ω Mo sheet resistance, and vertically stacked superconductive contact holes. We fabricated an eight-bit SFQ shift register, a one million SQUID array and a 16-kbit RAM by using the ADP. The shift register was operated up to 120 GHz and no short or open circuits were detected in the one million SQUID array. We confirmed correct memory operations by the 16-kbit RAM and a 5.7 times greater integration level compared to that possible with the SDP.

This paper describes a robust automatic speech recognition (ASR) system with less computation. Acoustic models of a hidden Markov model (HMM)-based classifier include various types of hidden factors such as speaker-specific characteristics, coarticulation, and an acoustic environment, etc. If there exists a canonicalization process that can recover the degraded margin of acoustic likelihoods between correct phonemes and other ones caused by hidden factors, the robustness of ASR systems can be improved. In this paper, we introduce a canonicalization method that is composed of multiple distinctive phonetic feature (DPF) extractors corresponding to each hidden factor canonicalization, and a DPF selector which selects an optimum DPF vector as an input of the HMM-based classifier. The proposed method resolves gender factors and speaker variability, and eliminates noise factors by applying the canonicalzation based on the DPF extractors and two-stage Wiener filtering. In the experiment on AURORA-2J, the proposed method provides higher word accuracy under clean training and significant improvement of word accuracy in low signal-to-noise ratio (SNR) under multi-condition training compared to a standard ASR system with mel frequency ceptral coeffient (MFCC) parameters. Moreover, the proposed method requires a reduced, two-fifth, Gaussian mixture components and less memory to achieve accurate ASR.

Permutation ambiguity of the classical Independent Component Analysis (ICA) may cause problems in feature extraction for pattern classification. Especially when only a small subset of components is derived from data, these components may not be most distinctive for classification, because ICA is an unsupervised method. We include a selective prior for de-mixing coefficients into the classical ICA to alleviate the problem. Since the prior is constructed upon the classification information from the training data, we refer to the proposed ICA model with a selective prior as a supervised ICA (sICA). We formulated the learning rule for sICA by taking a Maximum a Posteriori (MAP) scheme and further derived a fixed point algorithm for learning the de-mixing matrix. We investigate the performance of sICA in facial expression recognition from the aspects of both correct rate of recognition and robustness even with few independent components.

LSI on-chip optical interconnections are discussed from the viewpoint of a comparison between optical and electrical interconnections. Based on a practical prediction of our optical device development, optical interconnects will have an advantage over electrical interconnects within a chip that has an interconnect length less than about 10 mm at the hp32-22 nm technology node. Fundamental optical devices and components used in interconnections have also been introduced that are small enough to be placed on top of a Si LSI and that can be fabricated using methods compatible with CMOS processes. A SiON waveguide showed a low propagation loss around 0.3 dB/cm at a wavelength of 850 nm, and excellent branching characteristics were achieved for MMI (multimode interference) branch structures. A Si nano-photodiode showed highly enhanced speed and efficiency with a surface plasmon antenna. By combining our Si nano-photonic devices with the advanced TIA-less optical clock distribution circuits, clock distribution above 10 GHz can be achieved with a small footprint on an LSI chip.

In this study, we introduce a software pipeline to track feature points across endoscopic video frames. It deals with the common problems of low contrast and uneven illumination that afflict endoscopic imaging. In particular, irregular feature trajectories are eliminated to improve quality. The structure of soft tissue is determined by an iterative factorization method based on collection of tracked features. A shape updating mechanism is proposed in order to yield scale-invariant structures. Experimental results show that the tracking method produced good tracking performance and increased the number of tracked feature trajectories. The real scale and structure of the target scene was successfully estimated, and the recovered structure is more accuracy than the conventional method.

The average bit error rate performances of M-ary orthogonal code shift keying (CSK) in Rician fading environments are analyzed in this letter. CSK is a digital modulation scheme that uses a code set as M-ary signals. In CSK, one code is selected from a code set containing M codes according to the information data. A signal is modulated by using this code and the effect of fading can be reduced by applying interleaving to the elements of the codes. In the analysis, the bit error probability is derived in closed form expression by using the Chernoff bound. The analysis results show that the error probability decreases when the code length is increased and that an arbitrarily small error probability is achieved as the code length approaches infinity, provided that Eb/N0 exceeds 1.42 dB.

In Distributed detection systems, restricting the output of the local decision to one bit certainly implies a substantial information loss. In this paper, we consider the fuzzy detection, which uses a function called membership function for mapping the observation space of each local detector to a value between 0 and 1, indicating the degree of assurance about presence or absence of a signal. In this case, we examine the problem of distributed Maximum Likelihood (ML) and Order Statistic (OS) constant false alarm rate (CFAR) detections using fuzzy fusion rules such as "Algebraic Product"(AP), "Algebraic Sum"(AS), "Union"(Un) and "Intersection"(IS) in the fusion centre. For the Weibull clutter, the expression of the membership function based on the ML or OS CFAR processors in the local detectors is also obtained. For comparison, we consider a binary distributed detector, which uses the Maximum Likelihood and Algebraic Product (MLAP) or Order Statistic and Algebraic Product (OSAP) CFAR processors as the local detectors. In homogenous and non homogenous situations, multiple targets or clutter edge, the performances of the fuzzy and binary distributed detectors are analyzed and compared. The simulation results indicate the superior and robust performance of the distributed systems using fuzzy detection in the homogenous and non homogenous situations.

In this paper, we present a clean and simple formulation of survey propagation (SP) for constraint-satisfaction problems as "probabilistic token passing". The result shows the importance of extending variable alphabets to their power sets in designing SP algorithms.

Burn-in is a widely used method to improve the quality of products or systems after they have been produced. In this paper, optimal burn-in procedures for a system with two types of failures (i.e., minor and catastrophic failures) are investigated. A new system surviving burn-in time b is put into field operation and the system is used under a warranty policy under which the manufacturer agrees to provide a replacement system for any system that fails to achieve a lifetime of at least w. Upper bounds for optimal burn-in time minimizing the total expected warranty cost are obtained under a more general assumption on the shape of the failure rate function which includes the bathtub shaped failure rate function as a special case.

This paper presents a new interactive learning method for spoken word acquisition through human-machine audio-visual interfaces. During the course of learning, the machine makes a decision about whether an orally input word is a word in the lexicon the machine has learned, using both speech and visual cues. Learning is carried out on-line, incrementally, based on a combination of active and unsupervised learning principles. If the machine judges with a high degree of confidence that its decision is correct, it learns the statistical models of the word and a corresponding image category as its meaning in an unsupervised way. Otherwise, it asks the user a question in an active way. The function used to estimate the degree of confidence is also learned adaptively on-line. Experimental results show that the combination of active and unsupervised learning principles enables the machine and the user to adapt to each other, which makes the learning process more efficient.

Reducing the rate of false positives is of vital importance in enhancing the usefulness of signature-based network intrusion detection systems (NIDSs). To reduce the number of false positives, a network administrator must thoroughly investigate a lengthy list of signatures and carefully disable the ones that detect attacks that are not harmful to the administrator's environment. This is a daunting task; if some signatures are disabled by mistake, the NIDS fails to detect critical remote attacks. We designed a NIDS, TrueAlarm, to reduce the rate of false positives. Conventional NIDSs alert administrators that a malicious message has been detected, regardless of whether the message actually attempts to compromise the protected server. In contrast, TrueAlarm delays the alert until it has confirmed that an attempt has been made. The TrueAlarm NIDS cooperates with a server-side monitor that observes the protected server's behavior. TrueAlarm only alerts administrators when a server-side monitor has detected deviant server behavior that must have been caused by a message detected by a NIDS. Our experimental results revealed that TrueAlarm reduces the rate of false positives. Using actual network traffic collected over 14 days, TrueAlarm produced 46 false positives, while Snort, a conventional NIDS, produced 818.

This paper deals with redundant 3D mesh processor arrays using 1.5-track switches, considering track and switch faults together with processor faults. Four variants are defined based on the distributions of spare PEs, and arrays of three variants have the same PE redundancies among them, but the fabrication-time costs are different. We investigate in detail how the reliability of a total system changes according to the reliabilities of tracks and switches as well as PEs, and show the concrete values of Mt and Ms, when the reliability of array are almost the same even if its variant is changed, and when it is not so, respectively, where Mt and Ms are the ratio of the hardware complexities of a PE and a track, and that of a PE and a contact point of a switch, respectively. Other results which are effective basis for the design of fault-tolerant 3D PE arrays using 1.5-TSs are given.

Multi-carrier code division multiple access (MC-CDMA) has been considered as one of the promising techniques for the next generation of mobile communication systems because of its efficient bandwidth usage, robustness to the multi-path fading and simple channel-sharing scheme. However, MC-CDMA cannot be employed in the uplink communication where the transmitted signal from each user propagates through the different multi-path fading channel, and the received signals are no longer orthogonal at the base station. As a result, bit error rate (BER) performance in the uplink MC-CDMA communication would be strongly degraded due to the occurrence of multi-user interference (MUI). To solve the MUI problem in the uplink MC-CDMA, the pre-equalization method was proposed in which the uplink signal is pre-equalized at the user terminal by using the channel response estimated from the downlink. Although the pre-equalization method is very effective for the stationary uplink channel with fixed users, it is hard to be employed in the time varying fading channel with mobile users, because there is a big difference in the channel responses between downlink and uplink. For the efficient MUI compensation, each user terminal would be required to predict the future channel conditions based on the current observation. This paper proposes a method for model based uplink channel response prediction by employing the spectral decomposition of the downlink channel impulse response. Computer simulation results show that the proposed method can achieve the accurate prediction of channel response for mobile users during the uplink transmission and allows the effective MUI compensation.

Multiple-Input Multiple-Output (MIMO) systems that realize high-speed data transmission with multiple antennas at both transmitter and receiver are drawing much attention. In line-of sight (LOS) environments, the performance of MIMO systems depends largely on the difference of the phase difference of direct paths from transmit antennas to each receive antenna. When the phase difference of direct paths are close to each other, the spatial division multiplexing (SDM) channels are not orthogonal to each other so signal detection becomes difficult. In this paper, we propose a MIMO system with relative phase difference time-shift modulation (RPDTM) in Rician fading environments. The proposed scheme transmits independent signals from each antenna at each time slot where the relative phase difference between signal constellations used by transmit antennas varies in a pre-determined pattern. This transmission virtually changes the phase difference of direct paths from transmit antennas to each receive antenna without lowering data rate and without knowledge of the channels. In addition, forward error correction coding (ECC) is applied to exploit the time slots where the receiver can detect the signals easily to improve the detection performance. If there are time slots where the receiver can separate the received signal, the receiver can decode the data by using the time slots and the correlation between data. From the results of computer simulation, we show that MIMO system with RPDTM can achieve the better bit error rate (BER) than the conventional MIMO system. We also show that the MIMO system with RPDTM is effective by about Rician factor K = 10 dB.

In this paper we propose an algorithm of factoring any integer N which has k different prime factors with the same bit-length, when about ()log2 N high-order bits of each prime factor are given. For a fixed ε, the running time of our algorithm is heuristic polynomial in (log2 N). Our factoring algorithm is based on a lattice-based algorithm of solving any k-variate polynomial equation over Z, which might be an independent interest.

A fair exchange scheme is a protocol by which two parties Alice and Bob exchange items or services without allowing either party to gain advantages by quitting prematurely or otherwise misbehaving. To this end, modern cryptographic solutions use a semi-trusted arbitrator who involves only in cases where one party attempts to cheat or simply crashes. We call such a fair exchange scheme optimistic. When no registration is required between the signer and the arbitrator, we say that the fair exchange scheme is setup-free. To date, the setup-free optimist fair exchange scheme under the standard RSA assumption was only possible from the generic construction of [12], which uses ring signatures. In this paper, we introduce a new setup-free optimistic fair exchange scheme under the standard RSA assumption. Our scheme uses the GQ identity-based signature and is more efficient than [12]. The construction can also be generalized by using various identity-based signature schemes. Our main technique is to allow each user to choose his (or her) own "random" public key in the identity-based signature scheme.

A transverse magnetic (TM) plane wave is diffracted by a periodic surface into discrete directions. However, only the reflection and no diffraction take place when the angle of incidence becomes a low grazing limit. On the other hand, the scattering occurs even at such a limit, if the periodic surface is finite in extent. To solve such contradiction, this paper deals with the scattering from a perfectly conductive sinusoidal surface with finite extent. By the undersampling approximation introduced previously, the total scattering cross section is numerically calculated against the angle of incidence for several corrugation widths up to more than 104 times of wavelength. It is then found that the total scattering cross section is linearly proportional to the corrugation width in general. But an exception takes place at a low grazing limit of incidence, where the total scattering cross section increases almost proportional to the square root of the corrugation width. This suggests that, when the corrugation width goes to infinity, the total scattering cross section diverges and the total scattering cross section per unit surface vanishes at a low grazing limit of incidence. Then, it is concluded that, at a low grazing limit of incidence, no diffraction takes place by a periodic surface with infinite extent and the scattering occurs from a periodic surface with finite extent.

This paper deals with the scattering of a transverse magnetic (TM) plane wave from a perfectly conductive sinusoidal surface with finite extent. By use of the undersampling approximation and a rectangular pulse approximation, an asymptotic formula for the total scattering cross section at a low grazing limit of incident angle is obtained explicitly under conditions such that the surface is small in roughness and slope, and the corrugation width is sufficiently large. The formula shows that the total scattering cross section is proportional to the square root of the corrugation width but does not depend on the surface period and surface roughness. When the corrugation width is not large, however, the scattered wave can be obtained by a single scattering approximation, which gives the total scattering cross section proportional to the corrugation width and the Rayleigh slope parameter. From the asymptotic formula and the single scattering solution, a transition point is defined explicitly. By comparison with numerical results, it is concluded that the asymptotic formula is fairly accurate when the corrugation width is much larger than the transition point.