We exactly determine the number of negations needed to compute the parity functions and the complement of the parity functions. We show that with k NOT gates, parity can be computed on at most 2k+11 variables, and parity complement on at most 2k+12 variables. The two bounds are shown to be tight.

Graph unification is doubtlessly the most expensive process in unification-based grammar parsing since it takes the vast majority of the total parsing time of natural language sentences. A parsing time overload in unification consists in that, in general, no less than 60% of the graph unifications performed actually fail. Thus one way to achieve unification time speed-up is focusing on an efficient, fast way to deal with such unification failures. In this paper, a process, prior to unification itself, capable of filtering or stopping a considerably high percentage of graphs that would fail unification is proposed. This unification-filtering process consists of comparison of signatures that correspond to each one of the graphs to be unified. Unification-filter (hereafter UF) is capable of stopping around 87% of the non-unifiable graphs before unification itself takes place. UF takes significantly less time to detect graphs that do not unify and discard them than it would take to unification to fail the attempt to unify the same graphs. As a result of using UF, unification is performed in an around 71% of the time for the fastest known unification algorithm.

Self-modelocking of Ti:sapphire laser has obtained with less than 2 W of argon-ion laser pumping. Two independent lasers with 36 fsec and 63 fsec in pulse duration were operated by a 6 W pump laser. In the low-threshold lasers, not only an ordinary mode-locking but also a double-pulse mode-locking, where two pulses circulating in the cavity, was stable.

While Electro-Optic (E-O) sampling has achived the electric signal measurement with advantages of noninvasive, noncontact and ultrafast time resolution, it is unsuitable for measuring long logic patterns in fast ICs under the functional test conditions. To overcome this problem, a real time E-O probing using a continuous wave (CW) diode laser and a fast photodetector has been developed. By adopting a ZnTe E-O probe having a half-wave voltage of 3.6 kV, shot noise limited measurement with a frequency bandwidth of 480 MHz has been achieved using a low noise diode laser (wavelength of 780 nm, output power of 30 mW), a pin photodiode, a wideband low noise amplifier, and a digital oscilloscope having 500 MHz bandwidth as a waveform analyzer. The minimum detectable voltage was 23 mV under 700 times integration. In this paper, discussion of the voltage sensitivity of real time E-O probing is included. Key parameters for attaining the highly sensitive real time E-O probing are the sensitivity of the E-O probe and noises of the probing light and detection system.

For two finite disjoint sets P and Q of strings over an alphabet Σ, an alphabet indexing for P, Q by an indexing alphabet Γ with |Γ||Σ| is a mapping :ΣΓ satisfying (P)(Q), where :Σ*Γ* is the homomorphism derived from . We defined this notion through experiments of knowledge acquisition from amino acid sequences of proteins by learning algorithms. This paper analyzes the complexity of finding an alphabet indexing. We first show that the problem is NP-complete. Then we give a local search algorithm for this problem and show a result on PLS-completeness.

In formal specification languages for parallel processes, such as CSP and LOTOS, algebraic laws for basic operators are provided that can be used to transform process expressions, and in particular, composition of processes can be calculated using these laws. Process composition can be used to simplify and improve the specification, and also to prove properties of the specification such as deadlock absence. We here test the practicality of process composition using CSP and suggest useful techniques, working in an example with nontrivial size and complexity. We emphasize that the size explosion of composed processes, caused by interleaving of the events of component processes, is a serious problem. Then we propose a technique, which we name two-way pipe, that can be used to reduce the size of the composed process, regarded as a program optimization at specification level.

This paper discusses sign word segmentation methods and extraction of motion features for sign language recognition. Because Japanese sign language grammar has not yet been systematized and because sign language does not have prepositions, it is more difficult to use grammar and meaning information in sign language recognition than in speech recognition. Segmentation significantly improves recognition efficiency, so we propose a method of dividing sign language based on rests and on the envelope and minimum of motion speed. The sign unit corresponding to a sign word is detected based on the divided position using such features as the change of hand shape. Experiments confirmed the validity of word segmentation of sign language based on the temporal structure of motion.

We have fabricated a new analog memory with a floating gate as a key component to store synaptic weights for integrated artificial neural networks. The new analog memory comprises a tunnel junction (poly-Si/poly-si oxide/poly-Si sandwich structure), a thin-film transistor, two capacitors, and a floating gate MOSFET. The diffusion of the charges injected through the tunnel junction is controlled by switching operation of the thin-film transistor, and we refer to the new analog memory as switched diffusion analog memory (SDAM). The obtained characteristics of SDAM are a fast switching speed and an improved linearity between the potential of the floating gate and the number of pulse inputs. SDAM can be used in a neural network in which write/erase and read operations are performed simultaneously.

A highly reliable, operated efficiently, and scalable switching node is required for multivendor system management networks. This paper presents techniques for applying the Telecommunications Management Network (TMN) concept to a distributed switching node. First, we select the TMN protocol structures so as to minimize the command response time. To ensure efficient operation and flexible design of the operation, administration and maintenance (OA & M) software, we propose a command-message handling function for mapping managed objects (MOs) to the OA & M software. We have designed MO classes for switching-system-specific devices with a redundant configuration that ensures highly reliable system operation. The feasibility of these techniques have been confirmed on a prototype system.

The improved point-matching method with Mathieu function expansion for the accurate analysis of the W-type elliptical fiber with layers of any ellipticity is proposed. Results of our method are reliable, because we expand the electromagnetic fields by a sum of the complete set of wave functions in each layer of the fiber. Numerical results are presented for the highly-birefringent fibers with a hollow layer outside an elliptical core. It is found that such fibers can realize the large value of the modal birefringence as well as they can be suitable for the single-mode and single-polarization transmission. From the convergence tests, it is confirmed that the relative error of the modal birefringence is less than 0.01%. The comparison of our results with those by previously reported method is presented. The proposed method can be extended for analysis of the elliptical-core fibers with hollow pits and electromagnetic scattering by targets of the complex elliptical geometry.

This paper proposes a new approach to the management of large-scale communication networks. To manage large-scale communication networks effectively, it is essential to get a bird's-eye view of them when they are in their normal conditions. When an indication of faulty state is detected, the focus of the management is narrowed down to the faulty network elements until the appropriate granularity is reached. This management scheme is called multilevel network management in this paper, and it first explains the significance of this scheme for large-scale communication networks and presents some ideas on implementing this management scheme. It then proposes that system identification be used in multilevel network management. The system identification is used to measure transmission delays between two arbitrarily selected nodes in the networks, and multilevel network management is achieved by selecting those two nodes appropriately in accordance with the levels to be managed. Finally, it is demonstrated by computation simulation results that the proposed method is suitable for multilevel network management.

This paper proposes a suitable distributed computing model as the basis for building a network management system. Author has been studying a distributed reactive model, called Meta for this purpose at Cornell University. Effectiveness using Meta is to provide high level program interface for developing network management system, and programmers can achieve network management system with coding small amount of programs. It also realizes easy additions and modifications for network management application programs. To confirm the effectiveness of the proposal, the author has utilized Meta to implement an experimental network management system. The experimental system provides high level interfaces for monitoring and controlling network components. It also supports reliable communication over distributed nodes. Preliminary evaluation of the system shows that critical network management applications are provided within an appropriate response time for all applications provided by SNMP, with small development cost and easy system modification.

A simple method is presented to calculate the parasitic capacitance effect in the propagation delay of series-connected MOS (SCM) structures. This method divides SCM circuits into two parts and accurately calculates the contribution of each part to the difference from the delay without parasitic capacitances.

Trouble management is a key function in solving the problems and maintaining the high communications capability of a network when communication service network users encounter problems in the quality of services [1]. This paper proposes technologies and architecture for an intelligent management system to achieve advanced service/network trouble management. The system generates operation scenarios to find a cause to solve a reported trouble, executes them, and modifies them according to operation circumstance changes. In the scenario execution process, fault propagation simulation is used to isolate a fault in necessary cases. The evaluation of the system applied to the ISDN services shows that the proposed system can achieve high-speed, precise trouble management by the integrated cooperative work of a human (operator) and a machine (operation system).

This paper describes a new algorithm for calculating exact statistics on directional data and its application to pattern processing. Although information about directional characteristics is practically useful in image processing, e.g. texture analysis or color segmentation, dominant information is not always extracted as exact statistics on directional data. The main reason is concerned with periodicity inherent in directional data. For example, an expectation of a random variable X is defined as ∫xp(x)dx, where p(x) is a probability density function of X; therefore, when a random direction D is distributed only at 170[]and 170[] with same probability density, the expectation of D leads to 0[] if nothing about the periodicity is considered. We would, however, expect that the exact expectation of D should be 180[]. To overcome the problem, we, at first, define a directional distance in such a form that can introduce the periodicity. Then, we propose an idea of defining directional statistics by a problem of minimizing an arithmetic mean of squared directional distances to each sample direction. Because the periodicity is introduced to the directional distance definition, the directional statistics are calculated as the exact statistics on directional data. Although the introduced periodicity might cause the minimization to be complex, we can compensate the complexity by introducing recurrence formulas; consequently, dominant information can efficiently be extracted as the directional statistics from those data. Experiments on their applications to pattern processing show that the proposed algorithm works well in detecting (1) divergent points of distorted vector field patterns with noise and (2) moving directions from translational movement vector fields.

This paper proposes a method for constructing an interface between an operations system and a workstation (OpS-WS interface) in a telecommunications management system based on TMN. To construct this interface, an appropriate communication protocol must be selected to perform management through efficient message exchange. The human machine interface provided by the WS should specify the managed objects. The interface also needs to be implemented so as to minimize the software revisions needed when the computer or its associated window system, or both, are changed. The proposed method addresses all these requirements. GUI components for realizing the HMI function are defined as Managed Objects as are communication network resources. Therefore, the communication protocol in TMN is defined as unique and it is possible to separate the HMI Interface from the OpS. CMIP is employed as the communication protocol to provide efficient message exchange. Software components that realize the human machine interface are selected so as to satisfy functional requirements specific to telecommunications management. The managed objects (MOs) and their relationships are investigated in order to represent these components appropriately. In the proposed method, the CMIP-based OpS-WS interface allows the OpS to take the manager role and the WS take the agent role. An implementation technique for MOs is also presented. The technique enables the software that implements MO behaviour to be coded easily. A prototype is built to confirm the correct operation of the proposed OpS-WS interface, and it is shown that CMIP requires fewer message exchanges to indicate alarms on the WS than other protocols. The proposed method is also advantageous because of its flexibility. That is, the WS software can be updated with little effort when the computer or its associated window system, or both, are changed.

This paper proposes a multi-fisheye distortion method which can show a large-scale telecommunication network in a single window on the display of a workstation or personal computer. This distortion method has three advantages over the conventional single-fisheye distortion method. First, the focus area is magnified smoothly by the fisheye distortion method, and the peripheral area coordinates are calculated linearly to avoid unnecessary distortion. Second, multiple focus areas are magnified smoothly by using an average of the coordinates calculated for the individual focuses. Third, the scale of unnecessary areas is reduced to provide sufficient space for magnification. The effectiveness of this method is demonstrated by applying to the display of large-scale networks. The effect of the resulting network map distortion on the user is tested by a subjective evaluation experiment.

Most current management systems employ graphic-user-interface displays to visualize the networks being managed. Some networks are so large that it is difficult to display all network elements in a single window alone, and therefore, the hierarchical multi-window style presentation is commonly used. This form of presentation has disadvantages, however, including the fact that window manipulations are complex. Our approach (bifocal network visualization) is able to display both the context and any detail of a network within a single window, and overcomes the disadvantages of hierarchical multi-window presentation. We implemented this bifocal network visualization on a workstation using a frame buffer memory called DUALQUEST that is able to generate images in real-time and is simple to operate. This paper describes bifocal network visualization and its implementation. Furthermore, we present an experiment to compare our interface with conventional hierarchical multi-window presentation.

Managed Objects (MOs) can be specified by the combination of a static information model and a dynamic process model. First, this paper presents a mapping of attributes from a process model diagram to an information model diagram. Then, it introduces a concept of topology into these two models and proposes a hypothesis about the relationship of topology in these two models. To explicitly explain the hypothesis, it can be stated that all attributes of incoming or outgoing data related to a process in a process model are mapped to an information model where these attributes are interconnected by an explicit relationship which corresponds to a specific meaning, such as physical containment or logical connection. From an intuitive perspective, it can be said that if two attributes have a close topological relationship in a process model, the mapped attributes also have a close topological relationship in an information model. This hypothesis provides clues for determining whether there is an error in an attribute either in the process model or in the information model. By examining the way attributes of incoming or outgoing data related to a process are mapped to an information model, we can detect whether there is an error with respect to the process. The error correction is performed with the assistance of probability analysis. The method of error detection and correction can be implemented in a computer aided tool. Then, error detection on the attribute level becomes automatic, and error correction on the attribute level becomes interactive through the computer aided tool. Finally, the validity of the hypothesis is confirmed by analyzing ITU-T Recommendation M.3100. The specification of the fabric object class defined in M.3 100 is transformed into these two models and the hypothesis is validated for the analysis of the mapping between these two models.

A near-ring is an extended notion of a usual ring. Therefore a ring is a near-ring, but the converse does not necessarily hold. We investigate in this paper one-way functions associated with finite near-rings, and show that if there exists a one-way group homomorphism, there exists a one-way non-ring near-ring homomorphism (Theorem 1); if there exists a one-way ring homomorphism (Theorem 2). Further, we introduce a discrete logarithm problem over a finite near-ring, and show that the integer factoring is probabilistic polynomial-time Turing equivalent to a modified version of this problem (Theorem 3). Theorem 1 implies that under some standard cryptographic assumption, there is an affirmative but trivial solution to the extended version of the open question: Is there an encryption function f such that both f(x+y) and f(xy) are efficiently computed from given f(x) and f(y) ?