This paper proposes a surveillance system concept, which includes the analysis of fiber fault factors and monitored items, the architecture for diagnosing fiber degradation and the system configuration. Fiber faults are classified into two types. One is fiber failure caused by fiber axial tensile strain and the other is fiber loss increase caused by fiber bending and the absorption of hydrogen molecules. It was found that there is an urgent need for fiber axial strain monitoring, sensitive loss monitoring operating at longer wavelengths and water sensing, in order to detect the origin and early indications of these faults before the service is affected. Moreover, an algorithm for predicting and diagnosing fiber faults based on the detected results was investigated and systematized.

We propose an integrated smart cable operation system and its architecture for the future cable network. In the proposed architecture, an application programs and various modules are loosely coupled using a cable operation system platform. We anticipate the task flows for the future optical cable network operation in order to realize the proposed system and architecture. Each task flow is broken down into "atomic tasks." The task flow can be changed easily by combining these atomic tasks. We use an object-oriented design for designing the cable operation system platform. As a first step towards the construction of the proposed system a pre-prototype system was constructed and the results are shown.

A new capacitor over bit-line (COB) stacked capacitor memory cell was developed using a local interconnect poly-silicon layer to arrange a capacitor contact between bit-lines. This memory cell enables usable capacitor area to increase and capacitor contact hole depth to decrease. The hemispherical grain (HSG) silicon, whose effective surface area is twice that of ordinary poly-silicon, was utilized for the storage node to increase the storage capacitance without increasing the storage node height. The feasibility of achieving a 1.8 µm2 memory cell with 30 fF storage capacitance using a 7 nm-SiO2-equivalent dielectric film and a 0.5 µm-high HSG storage node has been verified for 64 MbDRAMs by a test memory device using a 0.4 µm CMOS process.

The subject of the paper is to propose an O(|V|+|E|) algorithm for the 3-edge-connectivity augmentation problem (UW-3-ECA) defined by "Given an undirected graph G0=(V,E), find an edge set E of minimum cardinality such that the graph (V,EE ) (denoted as G0+E ) is 3-edge-connected, where each edge of E connects distinct vertices of V." Such a set E is called a solution to the problem. Let UW-3-ECA(S) (UW-3-ECA(M), respectively) denote UW-3-ECA in which G0+E is required to be simple (G0+E may have multiple edges). Note that we can assume that G0 is simple in UW-3-ECA(S). UW-3-ECA(M) is divided into two subproblems (1) and (2) as follows: (1) finding all k-edge-connected components of a given graph for every k3, and (2) determining a minimum set of edges whose addition to G0 result in a 3-edge-connected graph. Concerning the subproblem (1), we use an O(|V|+|E|) algorithm that has already been existing. The paper proposes an O(|V|+|E|) algorithm for the subproblem (2). Combining these algorithms makes an O(|V|+|E|) algorithm for finding a solution to UW-3-ECA(M). Furthermore, it is shown that a solution E to UW-3-ECA(M) is also a solution to UW-3-ECA(S) if |V|4, partly solving an open problem UW-k-ECA(S) that is a generalization of UW-3-ECA(S).

Two kinds of nitrided ultrathin (510 nm) SiO2 films were formed on the silicon (100) face using rapid thermal NH3-nitridation (RTN) and rapid thermal N2O-oxynitridation (RTON) technologies. The MOS capacitors with RTN SiO2 film showed that by Fowler-Nordheim (F-N) electron injection, both electron trap density and low-field leakage increase by the NH3-nitridation. In addition, the charge-to-breakdown (QBD) value decreases owing to NH3-nitridation. By contrast, RTON SiO2 films exhibited extremely low electron trap density, almost no increase of the leakage current, and large QBD value above 200C/cm2. The oxide film composition was evaluated by secondary ion mass spectroscopy (SIMS). The chemical bonding states were also examined by Fourier transform-infrared reflection attenuated total reflectance (FT-IR ATR) and X-ray photoelectron spectroscopy (XPS) measurements. These results indicate that although a large number of nitrogen (N) atoms are incorporated by the RTN and RTON, only the RTN process generates the hydrogen-related species such as NH and SiH bounds in the film, whereas the RTON film indicates only SiN bonds in bulk SiO2. From the dielectric and physical properties of the oxide films, it is considered that the oxide wearout by high-field stress is the result of the electron trapping process, in which anomalous leakage due to trap-assisted tunneling near the injected interface rapidly increases, leading to irreversible oxide failure.

The effects of low temperature etching for sub-half micron multi-layer resist are investigated. The low temperature etching with pure O2 gas provides higher anisotropic profiles than with an additional gas such as Cl2, N2. This is caused by the difference in the formative process of the side wall protection. With pure O2 gas at 80, highly anisotropic profiles for 0.35 µm patterns can be performed while the maximum tolerable width loss is below 0.03 µm.

We report on Brillouin optical-fiber time domain reflectometry (BOTDR) for distributed temperature or strain measurement along a single-mode optical fiber. BOTDR uses Brillouin scattering in optical fibers, whose Brillouin frequency shift increases in proportion to temperature or strain induced in the fiber. This method requires access to only one end of a fiber, as with conventional optical time domain reflectometry (OTDR) which uses Rayleigh scattering in optical fibers. In BOTDR, a coherent optical detection method is used as a backscattered light detection technique. This technique can achieve both high sensitivity and high frequency resolution and easily separate a weak Brillouin line from a strong Rayleigh scattering peak and Fresnel reflected light. Experimental results show the potential for measuring temperature and strain distribution with respective accuracies of 3 or 0.006%, and a spatial resolution of 100m in an 11.57km long fiber.

A novel CMOS structure has been developed using Ti-salicide PSD transistor formed by a new self-aligned method. Both N-channel and P-channel PSD transistors exhibit excellent short-channel behaviors down to the sub-half-micrometer region with shallow S/D junctions formed by dopant diffusion from polysilicons. New salicide process has been developed for the PSD structure and can effectively reduce the sheet resistances of the S/D polysilicon and the polysilicon gate to as low as 45Ω/. As a result, the low resistive local interconnects can be successfully implemented by the Ti-salicide S/D polysilicon merged with contacts by self-alignment. More-over it is found that shallow Ti-salicide S/D junctions with the PSD structure can achieve approximately 12 orders of magnitude lower area leakage current than that of the conventional implanted S/D junctions by eliminating implanted damage and preventing penetration of silicide into junctions with the elevated structure of S/D polysilicon layer. Furthermore CMOS ring oscillators having PSD transistors with an effective channel length of 0.4 µm were fabricated using the salicided S/D polysilicon as a local interconnect between the N+ and the P+ regions, and successfully operated with a propagation delay time of 50 ps/stage at a supply voltage of 5 V.

We designed and fabricated a prototype 0.4-µm-gate CMOS/SIMOX PLL LSI in order to verify the potential usefulness of ultrathin-film SIMOX technology for creating an extremely low-power LSI containing high-speed circuits operating at frequencies of at least 1 GHz and at low supply voltages. This PLL LSI contains both high-frequency components such a prescaler and low-frequency components such as a shift register, phase frequency comparator, and fixed divider. One application of the LSI could be for synthesizing communication band frequencies in the front-end of a battery-operated wireless handy terminal for personal communications. At a supply voltage of 2 V, this LSI operates at up to 2 GHz while dissipating only 8.4 mW. Even at only 1.2 V, 1 GHz-operation can be obtained with a power consumption of merely 1.4 mW. To explain this low-power feature, we extensively measured the electrical characteristics of individual CMOS/SIMOX basic circuits as well as transistors. Test results showed that the high performance of the LSI is mainly due to the advanced nature of the CMOS/SIMOX devices with low parasitic capacitances around source/drain regions and to the new circuit design techniques used in the dual-modulus prescalar.

Self-aligned aluminum-gate MOSFET's have been successfully fabricated by employing ultraclean ion implantation technology. The use of ultra high vacuum ion implanter and the suppression of high-energy ion-beam-induced metal sputter contamination have enabled us to form ultra-shallow low-leakage pn junctions by furnace annealing at a temperature as low as 450. The fabricated aluminum-gate MOSFET's have exhibited good electrical characteristics, thus demonstrating a large potential for application to realizing ultra-high-speed integrated circuits.

Copper contamination behavior is studied, depending on the pH level, conductivity type P or N of a silicon substrate, and contamination method of copper. If the pH level of a copper containing solution is adjusted by using ammonia, copper atoms and ammonia molecules produce copper ion complexes. Accordingly, the amount of copper adsorption on the substrate surface is decreased. When N-type silicon substrates are contaminated by means of copper containing solutions, copper atoms on the surfaces diffuse into bulk crystal even at room temperature. But for P-type silicon substrates, copper atoms are transferred into bulk crystal only after high temperature annealing. In the case of silicon substrates contaminated by contact with metallic copper, no copper atom diffusion into bulk crystal was observed. The above mentioned copper contamination behavior can be explained by the charge transfer interaction of copper atoms with silicon substrates.

Improvement of fatigue behavior of a fusion spliced portion on a carbon-coated fiber is achieved by recoating carbon using a thermal-CVD process with a CO2 laser as a local heat source. The fatigue parameters, so-called n-values, of 121 and 94 are obtained on the non-spliced portion and the spliced portion, respectively. Assuming a life time prediction model, these high values have been proved to have an advantage in a long-term reliability and to be sufficient in a practical submarine cable use.

Optical soliton transmissions at 10 and 20Gbit/s over 1000km with the use of erbium-doped fiber amplifiers are described in detail. For the 10Gbit/s experiment, a bit error rate (BER) of below 110-13 was obtained with 220-1 pseudorandom patterns and the power penalty was less than 0.1dB. In the 20Gbit/s experiment optical multiplexing and demultiplexing techniques were used and a BER of below 110-12 was obtained with 223-1 pseudorandom patterns under a penalty-free condition. A new technique for sending soliton pulses over ultralong distances is presented which incorporates synchronous shaping and retiming using a high speed optical modulator. Some experimental results over 1 million km at 7.210Gbit/s are described. This technique enables us to overcome the Gordon-Haus limit, the accumulation of amplified spontaneous emission (ASE), and the effect of interaction forces between adjacent solitons. It is also shown by computer runs and a simple analysis that a one hundred million km soliton transmission is possible by means of soliton transmission controls in the time and frequency domains. This means that limit-free transmission is possible.

This paper studies a method for a parallel implementation of digital half toning technique, which converts continuous tone images into monotone one without losing fidelity of images. A new modified algorithm for half toning is proposed, which is able to be implemented on a rectangular or one dimensional parallel multi-processor array as a part of extensions of space partitioning image processings. The purpose of this paper is primarily to apply space partitioning local image processing technique to nonlinear recursive algorithms. The target is to achieve a fast half toning with high quality. For that propose, local directional error diffusion techniques will be introduced, which enable original recursive error diffusion half toning to be converted into a local processing algorithm without losing its original advantages of producing high quality images. The characteristics of proposed methods will be analyzed and the advantages of our algorithm of high speed processing and high quality will be demonstrated by showing the results of simulations for typical examples.

Selective epitaxial growth technology has been extended to the base formation of a transistor on the basis of the SATURN (Self-Alignment Technology Utilizing Reserved Nitride) process, a high-speed bipolar LSI processing technology. The formation of a self-aligned base contact, coupled with SIC (Selective Ion-implanted Collector) fabricated by lowenergy ion implantation, has not only narrowed the transistor active regions but has drastically reduced the base width. A final base width of 800 and a maximum cut-off frequency of 31 GHz were achieved.

In this paper, we discuss secure protocols for shared computation of algorithms associated with digital signature schemes based on discrete logarithms. Generic solutions to the problem of cooperatively computing arbitraty functions, though formally provable according to strict security notions, are inefficient in terms of communication--bits and rounds of interaction--; practical protocols for shared computation of particular functions, on the other hand, are often shown secure according to weaker notions of security. We propose efficient secure protocols to share the generation of keys and signatures in the digital signature schemes introduced by Schnorr (1989) and ElGamal (1985). The protocols are built on a protocol for non-interactive verifiable secret sharing (Feldman, 1987) and a novel construction for non-interactively multiplying secretly shared values. Together with the non-interactive protocols for shared generation of RSA signatures introduced by Desmedt and Frankel (1991), the results presented here show that practical signature schemes can be efficiently shared.

To construct a Fiber-To-The-Home network, high count optical fiber cables are needed. The requirements for these cables are small diameter, light weight, and high capacity. We studied the cable structures for ribbon fiber, which are useful for quick splicing. We calculated the diameter of three types of cables: a slotted rod cable, a loose tube cable and a newly developed U-groove cable. When the same ribbons are cabled with the same clearance, the cross sectional area of the U-groove cablet is about 27% less than that of the other two cables. No problems with the manufactured 1500-fiber U-groove unit cable are detected by the conventional cable testing.

The 22 mechanical optical switch for single mode fiber (SMF) is reported. By using the precision grinding and molding techniques all-plastic multiple-fiber connector, 22 pin-referenced indirect slide switch is developed. The characteristics and the reliability test's results of this optical switch are also reported. Evaluations confirm that the switch has low insertion loss, high-speed switching, stable switching operations and reliability in practical applications.

Gradient-based methods for the computation of the velocity from image sequences assume that the velocity field varies smoothly over image. This creates difficulties at regions where the image intensity changes abruptly such as the occluding contours or region boundaries. In this letter, we propose a method to overcome these difficulties by incorporating the information of discontinuities in image intensity into a standard local optimization method. The presented method is applied to the synthetic and real images. The results show that the velocity field computed by the proposed method is less blurred at region boundaries than that of the standard method.

In this work, we introduce a fuzzy inference in conventional backpropagation learning algorithm, for networks of neuron like units. This procedure repeatedly adjusts the learning parameters and leads the system to converge at the earliest possible time. This technique is appropriate in a sense that optimum learning parameters are being applied in every learning cycle automatically, whereas the conventional backpropagation doesn't contain any well-defined rule regarding the proper determination of the value of learning parameters.