An associative memory model with a forgetting process a la Mezard et al. is investigated for a piecewise nonmonotonic output function by the SCSNA proposed by Shiino and Fukai. Similar to the formal monotonic two-state model analyzed by Mezard et al. , the discussed nonmonotonic model is also free from a catastrophic deterioration of memory due to overloading. We theoretically obtain a relationship between the storage capacity and the forgetting rate, and find that there is an optimal value of forgetting rate, at which the storage capacity is maximized for the given nonmonotonicity. The maximal storage capacity and capacity ratio (a ratio of the storage capacity for the conventional correlation learning rule to the maximal storage capacity) increase with nonmonotonicity, whereas the optimal forgetting rate decreases with nonmonotonicity.

An approximate scheme for decomposing and reconstructing a continuous-time signal as a linear combination of the B-splines is studied. It is an oversampling discrete-time implementation derived by substituting the multifold RRS functions for the B-splines. The RRS functions are multifold discrete convolution of the sampled rectangular functions. Analysis of the scheme yields conditions for the circuit parameters to assure stability and required precision. A design example is presented that makes the error less than 1% in the supremal norm by the oversampling ratio of 512. Its numerical simulation is also presented.

This paper addresses the important issue of estimating realistic grasping postures, and presents a methodology and algorithm to automate the generation of hand and body postures during the grasp of arbitrary shaped objects. Predefined body postures stored in a database are generalized to adapt to a specific grasp using inverse kinematics. The reachable space is represented discretely dividing into small subvolumes, which enables to construct the database. The paper also addresses some common problems of articulated figure animation. A new approach for body positioning with kinematic constraints on both hands is described. An efficient and accurate manipulation of joint constraints is presented. Obtained results are quite satisfactory, and some of them are shown in the paper. The proposed algorithms can find application in the motion of virtual actors, all kinds of animation systems including human motion, robotics and some other fields such as medicine, for instance, to move the artificial limbs of handicapped people in a natural way.

This paper presents a type inference algorithm for a logic language, HS. The algorithm uses a program transformation, SPS, to given programs as a type inference. This method is theoretically clear, because applying it to given programs is equal to executing it partially. No other additional framework is needed for our approach. In contrast, many studies on type inference for logic languages are based on Mycroft and O'Keefe's famous algorithm, which was initially developed for functional languages. Therefore, the meanings of the algorithms are theoretically unclear in the domain of logic languages. Our type inference is flexible. Users of the type inference system can specify the types of objects abstractly (weakly) if the types are not exactly known, or they can specify them particularly (strongly) if the types are exactly known. Both kinds of programs are inferred for types. In contrast, many type inference systems accept purely untyped programs. Thus, with these two features, our method is simple and flexible.

Parallel multiple context-free grammar (PMCFG) and multiple context-free grammar (MCFG) were introduced to denote the syntax of natural languages. By the known fastest algorithm, the recognition problem for multiple context-free language (MCFL) and parallel multiple context-free language (PMCFL) can be solved in O(ne) time and O(ne+1) time, respectively, where e is a constant which depends only on a given MCFG or PMCFG. In this paper, we propose the following two algorithms. (1) An algorithm which reduces the recognition problem for MCFL to the boolean matrices multiplication problem. (2) An algorithm which reduces the recognition problem for PMCFL to the recognition problem for MCFL. The time complexity of these algorithms is O(ne-3i+1 M(ni)) where e and i are constants which depend only on a given MCFG or PMCFG, and M(k) is the time needed for multiplying two k k boolean matrices. The proposed algorithms are faster than the known fastest algorithms unless e=e, i=1 for MCFG, and e=e, i=0 for PMCFG.

A formal verification approach that combines verification based on binary decision diagrams (BDDs) and theorem-prover-based verification has been developed. This approach is called the incremental formal verification approach. It uses an incremental verifier based on BDDs and a conventional theorem-prover-based verifier. Inputs to the incremental verifier are specifications in higher-level descriptions given in terms of arithmetic expressions, lower-level design descriptions given in terms of Boolean expressions, and constraints. The incremental verifier limits the behavior of the design by using the constraints, and compares the partial behavior limited by the constraints with the specifications by using BDD-based Boolean matching. It also replaces the matched part of the lower design description with equivalent constructs in the higher descriptions. Successive uses of the incremental verifier with different constraints can produce higher design descriptions from the lower design descriptions in a step-by-step manner. These higher descriptions are then input to the theorem-prover-based verification which enables faster treatment of larger circuits. Preliminary experimental results show that the incremental verifier can successfully check the partial equivalence and replace the matched parts by higher constructs.

Due to a rather low phoneme recognition rate for noisy telephone speech, there may arise large differences between N-gram built upon recognized phoneme labels and those built upon original attached phoneme labels, which in turn would affect the performances of N-gram based language identification methods. Use of N-gram built upon recognized phoneme labels from the training data was evaluated and was shown to be more effective for the language identification. The performance of mixed phoneme recognizer, in which both language-dependent and language-independent phonemes were included, was also evaluated. Results showed that the performance was better than that using parallel language-dependent phoneme recognizers in which bias existed due to different numbers of phonemes among languages.

One of unique features of CDMA slotted ALOHA (CDMA S-ALOHA) is that user must synchronize his transmission to given slot. Thus orthogonal sequence as spreading sequence would achieve ideal throughput if each of packets accomplish perfect synchronization. In the presence of any ambiguity in synchronizations, however, quasi-synchronous (QS) sequences suit well with CDMA S-ALOHA system. In this paper, we introduce new QS-sequences obtained from the orthogonal Gold sequences and discuss their performance when applying to CDMA S-ALOHA systems. As a result, withstanding to access timing error, good performance is ensured with this sequence under the environment of AWGN, MAI (multiple access interference) and frequency non-selective fading, that is, micro or pico cellular systems and indoor wireless LANs.

In this paper, we describe the implementation of the proposed single user type CDMA adaptive interference canceller (AIC) with RAKE structure in the developed testbed for the base station, and evaluate its performance in the multiuser and multipath fading environment. Laboratory experiment demonstrates that the AIC receiver is much more near-far resistant than the conventional matched filter (MF) receiver in the multiuser case. When the power of the other users is 6 dB larger than that of the desired user, the AIC receiver can achieve the BER of 10-3 at C/PG = 33. 3 % in the 2-path fading channel, while the MF receiver cannot achieve the BER at C/PG of more than 20. 8%. Furthermore, we evaluate the effect of transmission power reduction in the transmitter with transmission power control (TPC). The experimental result shows that the required transmission power can be greatly reduced by 3. 0 dB and 9. 2 dB with the AIC receiver at C/PG = 29. 2 % and 33. 3%, respectively.

One-way sensing simple multihead finite automata with bounds on the number of times of use of sensing function in accepting computations are studied. It is shown that the languages accepted by one-way sensing simple multihead finite automata with constant sensing function bound satisfy the semilinear property, and that for one-way sensing simple multihead finite automata, m+1 times of the use of sensing function are better than m.

This paper describes a new Artificial Neural Network (ANN), UNItary Decomposition ANN (UNIDANN), which can perform the unitary eigendecomposition of the synaptic weight matrix. It is shown both analytically and quantitatively that if the synaptic weight matrix is Hermitian positive definite, the neural output, based on the proposed dynamic equation, will converge to the principal eigenvectors of the synaptic weight matrix. Compared with previous works, the UNIDANN possesses several advantageous features such as low computation time and no synchronization problem due to the underlying analog circuit structure, faster convergence speed, accurate final results, and numerical stability. Some simulations with a particular emphasis on the applications to high resolution bearing estimation problems are also furnished to justify the proposed ANN.

To improve the resolution of the color CRTs, we propose a new electrostatic lens system which has two additional electrodes between the focus electrode and the anode electrode. The anode voltage and focus voltage are supplied on these additional electrodes. The numerical simulation shows that the system can reduce the third order aberration coefficients almost up to 31% of the conventional system. And the experiments show that the typical beam spot diameter is improved by nearly 20% of the conventional system.

In this paper, a new overload control strategy is proposed for a call control processor (CCP) in the base station controller (BSC) and processor utilization is measured. The proposed overload control strategy can regulate the call attempts by adopting measured processor utilization. A function, specifically a linear interpolation function based on Inverse Transform theory is used to convert controlled predictive average load rate in a call rejection rate. Then a call admission rate is obtained from the call rejection rate. Simulation shows that the proposed algorithm yields better performance than the conventional algorithm does under the heavy transient overload status in terms of call admission rate.

This letter reports on the condition for applying a feedback connection to a deterministic finite automata. First we define the partial delayed dependence condition for the feedback connection, and then consider problems related to the completeness problem of automata.

QoS of a multimedia interactive satellite communications system, which uses a satellite circuit for downlinks and a terrestrial network for uplinks, has been measured and evaluated under inferior satellite circuit conditions. Our attention in this paper is focused on TCP throughput as the most significant QoS, and experiments and analysis on TCP throughput were performed. The measured results are in good agreement with theoretical values calculated by taking congestion avoidance algorithms of TCP into consideration. As a result, we were able to verify that the TCP throughput declines radically when the low signal quality of a satellite circuit causes packet retransmission to occur. In this case, congestion avoidance works to reduce network congestion. The congestion avoidance increases the value of a retransmission timer and decreases the window size even if the network is not congested. Assuming that throughput deterioration is caused by rain fade, the total time when the throughput declines is less than 4 hours a year in Tokyo, and the results show the system can be put to practical use.

We propose and demonstrate a simple polarization-independent construction of a local node for optical WDM ring networks using a centralized multiwavelength light source (MWLS). The node is simply composed of a 4-port optical circulator, an add/drop multiplexing (ADM) filter, a reflective modulator, and a drop fiber Bragg grating (FBG). A Faraday rotator mirror (FRM) is used to enable an LiNbO3 intensity modulator to operate in the polarization-independent mode. We examine three ADM filters, an interference filter, a fiber Fabry-Perot (FP) filter, and a set of FBG's. An optical WDM system experiment is performed to demonstrate the feasibility of the proposed node construction.

An automatic defect classification system (ADC) for use in visual inspection of semiconductor wafers is introduced. The methods of extracting the defect features based on the human experts' knowledge, with their correlations with the defect classes are elucidated. As for the classifier, Hyperellipsoid Clustering Network (HCN) which is a layered network model employing second order discrimination borders in the feature space, is introduced. In the experiments using a collection of defect images, the HCNs are compared with the conventional multilayer perceptron networks. There, it is shown that the HCN's adaptive hyperellipsoidal discrimination borders are more suited for the problem. Also, the cluster encapsulation by the hyperellipsoidal border enables to determine rejection classes, which is also desirable when the system will be in actual use. The HCN with rejection achieves, an overall classification rate of 75% with an error rate of 18%, which can be considered equivalent to those of the human experts.

The Available Bit Rate (ABR) service of Asynchronous Transfer Mode (ATM) networks employs explicit rate notification algorithms to ensure better and fair distribution of available bandwidth among contending sources. The Enhanced Proportional Rate Control Algorithm (EPRCA) is one of the explicit rate control algorithms recommended by the ATM forum. In this paper, we identify deficiencies and problems associated with EPRCA and show that these cause unfairness in bandwidth utilization by the contending sources. We propose modification in EPRCA and call it Modified Enhanced Proportional Rate Control Algorithm (EPRCAM). We will argue and show through simulation results that EPRCAM leads to better link utilization and fair bandwidth allocation among contending sources. In our simulation model, EPRCAM results in as high as 97. 8% link utilization without cell loss.

This paper describes a factorization-based algorithm that reconstructs 3D object structure as well as motion from a set of multiple uncalibrated perspective images. The factorization method introduced by Tomasi-Kanade is believed to be applicable under the assumption of linear approximations of imaging system. In this paper we describe that the method can be extended to the case of truly perspective images if projective depths are recovered. We established this fact by interpreting their purely mathematical theory in terms of the projective geometry of the imaging system and thereby, giving physical meanings to the parameters involved. We also provide a method to recover them using the fundamental matrices and epipoles estimated from pairs of images in the image set. Our method is applicable for general cases where the images are not taken by a single moving camera but by different cameras having individual camera parameters. The experimental results clearly demonstrates the feasibility of the proposed method.

An enhanced priority reservation algorithm for ATM multicast switches with a one-shot scheduling scheme is proposed. This algorithm is an input reservation method in which priority is selected among input ports considering the number of rejected copy requests and the blocked age of head-of-line (HOL) cells. The operation procedure of the proposed algorithm is described, and the average cell-delay and throughput performance is evaluated by simulation. The simulation results show that the proposed algorithm yields better performance than the conventional algorithms.