Verb phrases are sometimes omitted in natural language (ellipsis). It is necessary to resolve the verb phrase ellipses in language understanding, machine translation, and dialogue processing. This paper describes a practical way to resolve verb phrase ellipses by using surface expressions and examples. To make heuristic rules for ellipsis resolution we classified verb phrase ellipses by checking whether the referent of a verb phrase ellipsis appears in the surrounding sentences or not. We experimented with the resolution of verb phrase elipses on a novel and obtained a recall rate of 73% and a precision rate of 66% on test sentences. In the case when the referent of a verb phrase ellipsis appeared in the surrounding sentences, the accuracy rate was high. But, in the case when the referent of a verb phrase ellipsis did not appear in the surrounding sentences, the accuracy rate was not so high. Since the analysis of this phenomena is very difficult, it is valuable to propose a way of solving the problem to a certain extent. When the size of corpus becomes larger and the machine performance becomes greater, the method of using corpus will become effective.

This paper proposes a quasi-coherent equivalent-time sampling method to acquire repetitive wideband waveform signals with high throughput. We have already proposed a new sampling system which incorporates the pre-trigger ability and the time jitter reduction function for a fluctuated input signal while maintaining the waveform recording efficiency. The quasi-coherent sampling method proposed in this paper can be adopted to it in order to improve its data acquisition throughput significantly. Numerical simulation results show effectiveness of our proposed method.

In this paper an analytical parametric formulation of total degradation in Orthogonal Frequency Division Multiplexing (OFDM) systems including High Power Amplifiers (HPA) is presented. Two classes of non-linear devices are considered: Traveling Wave Tube Amplifiers (TWTA) and Solid State Power Amplifiers (SSPA). In the results the accuracy of the proposed method is checked and the impact of coding to mitigate non-linear distortion is easily assessed.

Various types of wavelength-selectable light sources (WSLs) and wavelength-tunable laser diodes (LDs) have been developed, and the one based on an array of distributed feedback (DFB) laser diodes (LDs) has the advantage of tuning that is both simple and stable tuning. It requires only the selection of a DFB-LD and a temperature control. We report on monolithically integrated WSLs with a DFB-LD array, multimode interference (MMI) coupler, semiconductor optical amplifier (SOA), and electro-absorption (EA) modulator. To make them compact, we introduced microarray structures and to ensure that they were easy to fabricate, we used selective area growth. For the WSL with an integrated EA modulator, we developed a center-temperature-shift method that optimizes the detuning wavelength between the lasing wavelength and the absorption edge wavelength of the EA-modulator. Using this method, we obtained a uniform extinction ratio and were able to demonstrate error-free 2.5-Gb/s transmission over a 600-km fiber span. A CW-WSL without an EA-modulator should provide enough output power to compensate the loss caused by the external modulators, but the high-power operation of a CW-WSL is sensitive to optical feedback from the front facet. We therefore used an angled facet in our WSLs and eliminated a mode hop problem. More than 20 mW of fiber-coupled power was obtained over 23 ITU-T channels on a 50-GHz grid.

We studied various types of 2D and 3D Si-based photonic crystal structures that are promising for future photonic integrated circuit application. With regard to 2D SOI photonic crystal slabs, we confirmed the formation of a wide photonic bandgap at optical communication wavelengths, and used structural tuning to realize efficient single-mode line-defect waveguides operating within the bandgap. As regards 3D photonic crystals, we used a combination of lithography and the autocloning deposition method to realize complicated 3D structures. We used this strategy to fabricate 3D full-gap photonic crystals and 3D/2D hybrid photonic crystals.

Recently, feature maps have been applied to various problem domains. The success of some of these applications critically depends on whether feature maps are topologically ordered. Several different approaches have been proposed to improve the conventional self-organizing feature map (SOM) algorithm. However, these approaches do not guarantee that a topologically-ordered feature map can be formed at the end of a simulation. Therefore, the trial-and-error procedure still dominates the procedure of forming feature maps. In this paper, we propose a healing mechanism to repair feature maps that are not well topologically ordered. The healed map is then further fine-tuned by the conventional SOM algorithm with a small learning rate and a small-sized neighborhood set so as to improve the accuracy of the map. Two data sets were tested to illustrate the performance of the proposed method.

The Recursively Decomposable Interconnection Network (RDIN) is a set of interconnection networks that can be recursively decomposed into smaller substructures whose topologies and properties are similar to the original one. The examples of the RDIN are hypercubes, star graph, mesh, tree, pyramid, pancake, and WK-recursive network. This paper proposed a uniform and simple model to represent the RDIN inside computers at first. Based on the model, a generalized and efficient allocation scheme capable of being applied to all the members of the RDIN is developed. The proposed scheme can fully recognize the substructures (such as subcube, substar, subtree,. . . ) more easily than ever, and it is the first one that can fully recognize all the incomplete substructures. The best-fit allocation is also proposed. The criterion aims at keeping the largest free parts from being destroyed, as is the philosophy of the best-fit allocation. Moreover, the proposed scheme can be performed in an injured RDIN with its processors and/or links faulty. Finally, the mathematical analysis and simulations for two instances, hypercubes and star graphs, of the RDIN are presented. The results show that the generalized scheme outperforms or is comparable to the other proprietary allocation schemes designed for the specific structure.

Since components faults occurring at arbitrary places (primarily on the links) affect seriously network performance and reliability, the multicomputers operating in harsh environments should be designed to guarantee normal network-missions in presence of those faults. One solution to the end is a fault-tolerant routing scheme, which enables messages to safely reach their destinations avoiding failed links when transmission of messages is blocked by certain faults. In the paper, we develop a fault-tolerant routing algorithm with deadlock freedom in an n-dimensional meshed network, and validate its efficiency and effectiveness through proper simulations. The aspects of fault-tolerance is adopted by appending partial-adaptiveness and detouring to the e-cube algorithm, while using a wormhole routing for the backbone routing method. The phenomenon of deadlock incurred due to its adaptiveness is eliminated by classifying a physical channel into a couple of virtual channels.

System specifications should be refined to meet stakeholders' requirements as much as possible, because the first specification does not satisfy all stakeholders in general. This paper presents a procedure to refine behavioral specification to satisfy stakeholders. Non-functional requirements are used for checking stakeholders' satisfaction. With this procedure, stakeholder-dissatisfaction can be reduced and new possibilities to satisfy or dissatisfy other stakeholders can be found, since a modification to cancel dissatisfaction can sometimes influence the satisfaction of the others.

We describe hybrid integration technologies that employ silica-based planar lightwave circuit (PLC) platforms, and report several high-performance optical components based on these technologies. First, we describe the requirements for optical integrated circuits. Then, we discuss the technologies used in hybrid integration, namely optical coupling between a semiconductor optical device and a silica waveguide, electrical signal transmission to the semiconductor optical device, and high quality optical signal processing. In addition, we describe optical integrated circuits developed for short- and long-haul networks. We realized these high-performance integrated components by combining appropriate hybrid integration technologies.

An electric filed sensor using Mach-Zehnder interferometers has been designed to operate more than 10 GHz. The velocity of optical wave on the waveguide is investigated to determine the electrode length, and the characteristics of frequency response are analyzed using the moment method to determine the sensor element length. The electrode length of 1 mm and the element length of 8 mm are settled by these investigations. An isotropic electric field sensor is constructed using three sensors. The minimum detectable electric field strength is 22 mV/m at frequency bandwidth of 100 Hz. This is about 100 times for the conventional electric field sensor using the similar element. The sensitivity deviation is within 3 dB when temperature changes from 0 degree to 40 degree. The deviation of directivity can be tuned within 1 dB to calibrate the sensitivity of the each element. The sensitivity degradation is within 6 dB up to 5 GHz and within 10 dB up to 10 GHz. This is almost agree with the calculated results. The sensor can measure almost the same waveform as the applied electric field pulse whose width is 6 ns and rise time is less than 2.5 ns.

In order to construct optical access networks economically for fiber to the home (FTTH), it is important to reduce the cost of optical fiber cable installation. Optical fiber and cable costs have been reduced over the past ten years, however there have been few reports describing installation cost reduction. In this paper, we describe the design of high-density optical fiber cable that reduces the required installation time. To achieve this we have reduced the optical fiber cable weight and the friction coefficient of the cable sheath. We reduced the cable weight by using polyethylene foam and a non-metallic tensile strength member made of a new material, PBO. These two approaches reduce the cable weight by a total of about 30%. We also added a lubricant to the polyethylene sheath of this cable and this reduced the pulling force required for the additional cable by 30%-50%.

Using a full-vector finite element method (FEM) with curvilinear hybrid edge/nodal elements, a single-mode nature of index-guiding photonic crystal fibers, also called holey fibers (HFs), is accurately analyzed as a function of wavelength. The cladding effective index, which is very important design parameter for realizing a single-mode HF and is defined as the effective index of the infinite photonic crystal cladding if the core is absent, is also determined using the FEM. In traditional fiber theory, a normalized frequency, V, is often used to determine the number of guided modes in step-index fibers. In order to adapt the concept of V-parameter to HFs, the effective core radius, aeff, is determined using the actual numerical aperture given by the FEM. Furthermore, the group velocity dispersion of single-mode HFs is calculated as a function of their geometrical parameters, and the modal birefringence of HFs is numerically investigated.

We theoretically and experimentally demonstrate low loss branches in a Si photonic wire waveguide. Approximate calculation by the two-dimensional finite-difference time-domain (2-D FDTD) method and detailed design by the 3-D FDTD method indicate that low excess loss less than 0.2 dB is expected for a µm-size bend-waveguide-type branch at a wavelength of 1.55 µm. This branch is fabricated in a silicon-on-insulator substrate and the loss is evaluated to be 0.3 dB. This value is small enough to construct a very compact branching circuit.

This paper proposed an automated segmentation algorithm for MR brain images through the complementary use of T1-weighted, T2-weighted, and PD images. The proposed segmentation algorithm is composed of 3 steps. The first step involves the extraction of cerebrum images by placing a cerebrum mask over the three input images. In the second step, outstanding clusters that represent the inner tissues of the cerebrum are chosen from among the 3-dimensional (3D) clusters. The 3D clusters are determined by intersecting densely distributed parts of a 2D histogram in 3D space formed using three optimal scale images. The optimal scale image results from applying scale-space filtering to each 2D histogram and a searching graph structure. As a result, the optimal scale image can accurately describe the shape of the densely distributed pixel parts in the 2D histogram. In the final step, the cerebrum images are segmented by the FCM (Fuzzy c-means) algorithm using the outstanding cluster center value as the initial center value. The ability of the proposed segmentation algorithm to calculate the cluster center value accurately then compensates for the current limitation of the FCM algorithm, which is unduly restricted by the initial center value used. In addition, the proposed algorithm, which includes a multi spectral analysis, can achieve better segmentation results than a single spectral analysis.

In this paper, new integrated schemes of scheduling real-time traffic and cell loss control in high speed ATM networks are proposed for multiple priorities based on variable queue length thresholds for scheduling and the Partial Buffer Sharing policy for cell loss control. In our schemes, the queues for buffering arriving cells can be constructed in two ways: one individual queue for each user connection, or one physical queue for all user connections. The proposed schemes are considered to provide guaranteed QoS for each connection and cell sequence integrity for virtual channel/path characteristics. Moreover, these new schemes are quite flexible and can realize different scheduling algorithms. This paper also provides the Stochastic Petri Net models of these integrated schemes and an approximate analysis technique, which significantly reduces the complexity of the model solution and can be applied to real ATM switch models. From the numerical results, we can see that our schemes outperform those well-known schemes such as the head-of-line (HOL) priority control and the queue length threshold (QLT) policy.

We propose a set of Fabry-Perot etalons integrated in a planar lightwave circuit (PLC-FPE) designed for a unified system for broadcasting and communication. A PLC-FPE containing four etalons having different cavity lengths is fabricated and their loss and frequency characteristics are investigated. The total loss and the maximum finesse were found to be 8 dB and 34, respectively.

Low cost optical subscriber systems and effective operation are indispensable to the construction and maintenance of greatly expanded optical fiber networks. An optical fiber line monitoring system is essential for reducing maintenance costs and improving service reliability in optical access networks. To promote cost-effective optical fiber line operation, we propose an extended automatic optical fiber operations support system (AURORA) with a remotely installed fiber selector. We suggest a configuration for extended AURORA and design the dynamic range of the system. We confirmed that testing could be carried out on an extended optical network section of 10 km in length by using extended AURORA when the optical trunk line was less than 15 km. We also discuss the effect on the maintenance cost of optical fiber cables in access networks. We calculated the annual maintenance cost for periodic tests in actual operation areas, and confirmed that this cost could be reduced by 30% compared with that for a conventional system.

In this paper, we study system-level diagnosis under the comparison approach proposed by Maeng and Malek. Sengupta and Dahbura designed an O(n5) time diagnosis algorithm for identifying all faulty nodes in general graphs (n is the number of nodes in a system). We consider diagnosis on a butterfly network BF(k,r) and propose O(k2 n) time diagnosis algorithms for locating all faulty nodes in BF(k,r).

This paper presents a historical review of fiber technologies from the 1970s till now, focused on design, transmission characteristics, and reliability assurance of silica optical fibers. Discussion is made by dividing the period into two phases; the first phase closing nearly at the end of the 1980s and the second one starting at the same time. As for the first phase, we present designs of graded-index multimode fiber and single-mode fiber, and development of dispersion shifted fiber. Mechanical reliability assurance and loss increase phenomena due to hydrogen are also described. Development of an optical fiber amplifier triggered the start of the second phase. Due to the introduction of WDM transmission systems as well as demand on high bit-rate transmission, fiber dispersion and nonlinearity have become indispensable factors to be taken into consideration for system design and performance evaluation. We discuss novel non-zero dispersion shifted fibers and dispersion compensating fibers, developed to meet the requirements for long distance and high bit-rate WDM transmission systems. Finally, discussions are made on the future research and development items, which are necessary to realize anticipating photonic networks.