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541-560hit(726hit)

  • Formation of Ultra-Thin Organic Films by Micelle-Wrapping Sequential Adsorption Method

    Seimei SHIRATORI  Takahiro ITO  

     
    PAPER-Ultra Thin Film

      Vol:
    E83-C No:7
      Page(s):
    1094-1098

    Layer-by-layer sequential adsorption process of polyelectrolytes had conventionally been used for the fabrication of the ultra-thin organic film formed by various polymers with different polarity of charge. In this study, hydrophobic Ruthenium complex monomer (tris (bilyridyl) ruthenium (II) hexafluorophosphate) was micelle-wrapped with an anionic surfactant, sodium dodecylbenzenesulfonate, and was assembled with PAH (poly (allylamine hydrochloride)) which has the opposite charge on ITO substrates. With this method, we succeed in fabricating ultra-thin organic films even when the adsorption material is not polymer but monomer. Moreover it was found that the bilayer thickness of the self-assembled (Ru micelle/PAH) was systematically changed by adjusting the solution pH of each bath. By using this process, EL device was fabricated by depositing the thin film of micelle-wrapping ruthenium complex monomer on ITO and formed Bi electrode on top of the film. Light emission was observed by applying voltage to this device.

  • Fabrication of Coplanar Microstructures Composed of Multiple Organosilane Self-Assembled Monolayers

    Hiroyuki SUGIMURA  Atsushi HOZUMI  Osamu TAKAI  

     
    PAPER-Ultra Thin Film

      Vol:
    E83-C No:7
      Page(s):
    1099-1103

    Micropatterning of organosilane self-assembled monolayers (SAMs) was demonstrated on the basis of photolithography using an excimer lamp radiating vacuum ultra-violet (VUV) light of 172 nm in wavelength. This lithography is generally applicable to micropatterning of organic thin films including alkyl and fluoroalkyl SAMs, since its patterning mechanism involves cleavage of C-C bonds in organic molecules and subsequent decomposition of the molecules. In this study, SAMs were prepared on Si substrates covered with native oxide by chemical vapor deposition in which an alkylsilane, that is, octadecyltrimethoxysilane [CH3(CH2)17Si(OCH3)3, ODS] or a fluoroalkylsilane, that is, 1H, 1H, 2H, 2H-perfluorodecyltrimethoxy-silane [CF3(CF2)7CH2CH2Si(OCH3)3, FAS] were used as precursors. Each of these SAMs was photoirradiated through a photomask placed on its surface. As confirmed by atomic force microscopy and x-ray photoelectron spectroscopy, the SAMs were decomposed and removed in the photoirradiated area while the masked areas remained undecomposed. A micropattern of 2 µm in width was successfully fabricated. Furthermore, microstructures composed of two different SAMs, that is, ODS and FAS, were fabricated as follows. For example, an ODS-SAM was first micropatterned by the VUV-lithography. Since, the VUV-exposed region on the ODS-SAM showed an affinity to the chemisorption of organosilane molecules, the second SAM, i. e. , FAS, confined to the photolithographically defined pattern was successfully fabricated. Due to the electron negativity of F atoms, the FAS covered region showed a more negative surface potential than that of the ODS surface: its potential difference was ca. 120 mV as observed by Kelvin probe force microscopy.

  • A Distributed Approach against Computer Viruses Inspired by the Immune System

    Takeshi OKAMOTO  Yoshiteru ISHIDA  

     
    PAPER-Communication and Computer Architecture/Assurance Systems

      Vol:
    E83-B No:5
      Page(s):
    908-915

    More than forty thousands computer viruses have appeared so far since the first virus. Six computer viruses on average appear every day. Enormous expansion of the computer network opened a thread of explosive spread of computer viruses. In this paper, we propose a distributed approach against computer virus using the computer network that allows distributed and agent-based approach. Our system is composed of an immunity-based system similar to the biological immune system and recovery system similar to the recovery mechanism by cell division. The immunity-based system recognizes "non-self" (which includes computer viruses) using the "self" information. The immunity-based system uses agents similar to an antibody, a natural killer cell and a helper T-cell. The recover system uses a copy agent which sends an uninfected copy to infected computer on LAN, or receives from uninfected computer on LAN. We implemented a prototype with JAVATM known as a multi-platform language. In experiments, we confirmed that the proposed system works against some of existing computer viruses that can infect programs for MS-DOSTM.

  • OTA-C Based BIST Structure for Analog Circuits

    Cheng-Chung HSU  Wu-Shiung FENG  

     
    LETTER-VLSI Design Technology and CAD

      Vol:
    E83-A No:4
      Page(s):
    771-773

    In this letter, a novel built-in self-test (BIST) structure based on operational transconductance amplifiers and grounded capacitors (OTA-Cs) for the fault diagnosis of analog circuits is proposed. The proposed analog BIST structure, namely ABIST, can be used to increase the number of test points, sampling and controlling of all test points with voltage data, and making less time for test signal observable. Experimental measurements have been made to verify that the proposed ABIST structure is effective.

  • Matter-Conserved Replication Causes Computational Universality

    Kosaku INAGAKI  

     
    LETTER-General Fundamentals and Boundaries

      Vol:
    E83-A No:3
      Page(s):
    579-580

    Signal conservation logic (SCL) is a model of logic for the physical world subject to the matter conservation law. This letter proves that replication, complementary replication, and computational universality called elemental universality are equivalent in SCL. Since intelligence has a close relation to computational universality, the presented theorem may mean that life under the matter conservation law eventually acquires some kind of intelligence.

  • Fault-Tolerance of Distributed Algorithms: Self-Stabilization and Wait-Freedom

    Toshimitsu MASUZAWA  Michiko INOUE  

     
    INVITED SURVEY PAPER-Parallel and Distributed Algorithms

      Vol:
    E83-D No:3
      Page(s):
    550-560

    Distributed computation has attracted considerable attention and large-scale distributed systems have been designed and developed. A distributed system inherently has possibility of fault tolerance because of its redundancy. Thus, a great deal of investigation has been made to design fault-tolerant distributed algorithms. This paper introduces two promising paradigms, self-stabilization and wait-freedom, for designing fault-tolerant distributed algorithms and discusses some subjects important from the point of view of algorithm engineering.

  • New Self-Healing Scheme that Realizes Differentiated Bandwidth Requirement on ATM Networks

    Taishi YAHARA  Ryutaro KAWAMURA  Satoru OHTA  

     
    PAPER-Signaling System and Communication Protocol

      Vol:
    E83-B No:3
      Page(s):
    672-679

    This paper proposes a new self-healing scheme that differentiates the bandwidth requirement for each network service on ATM networks. First, we show the necessity of our proposed scheme. In the future network, we must satisfy two demands, rapid restoration from failure and differentiated bandwidth requirements. The conventional restoration scheme, called the self-healing scheme, realizes rapid restoration, but does not support bandwidth differentiation; the new self-healing scheme proposed herein does. We also show that the proposed scheme reduces the spare resources required for backup. The scheme can be realized as a simple extension of the conventional self-healing scheme. Finally, simulations show that the proposed scheme requires fewer spare resources while offering comparable restoration time to the conventional approach against any demand pattern.

  • Optical Fiber Humidity Sensor with a Fast Response Time Using the Ionic Self-Assembly Method

    Francisco J. ARREGUI  Kristie L. COOPER  Yanjing LIU  Ignacio R. MATIAS  Richard O. CLAUS  

     
    PAPER-Chemical, Environmental, Biochemical and Medical Sensors

      Vol:
    E83-C No:3
      Page(s):
    360-365

    An optical fiber humidity sensor was fabricated forming a nanometer-scale Fabry-Perot interferometer by using the Ionic Self-Assembly Monolayer (ISAM) method. The materials used were Poly R-478 and poly(diallyldimethyl ammonium chloride). Taking advantage of the precision that the ISAM method can achieve in controlling the length of the nano cavity, the length was fit to obtain a maximum variation of 8.7 dB of reflected optical power between 11.3% and 85% RH. The sensor exhibited a fast response time and was able to monitor the human breathing.

  • A Method for Finding the Direction of Arrival of a Single Short Pulse by the Waveform Reconstruction

    Masanori ISHII  Takashi IWASAKI  

     
    PAPER-EMC Measurement and Test

      Vol:
    E83-B No:3
      Page(s):
    453-459

    In this paper, a method for finding the direction of arrival (DOA) of a single short pulse is proposed. The method is based on a waveform reconstruction technique using complex antenna factors (CAF). Since the frequency characteristics of CAF has angle dependency, the DOA of an electromagnetic pulse can be determined by the waveforms reconstructed with CAF. The results of a simulation and an experiment show the possibility to apply the two-dimensional DOA finding.

  • Preplanned Restoration and Optimal Capacity Placement on ATM Multicast Tree

    Yih-Fuh WANG  Jen-Fa HUANG  

     
    PAPER-Traffic Control and Network Management

      Vol:
    E83-B No:2
      Page(s):
    281-292

    The ATM multicast Tree (AMT) is the Mbone of video/audio conferencing and other multicasting applications in ATM (Asynchronous Transfer Mode) networks. However, real problems such as temporarily moving switches, changing optic fiber connections and/or tangible/intangible failures of ATM networks will cause many service disruptions. Thus we must carefully consider the system's SQOS (Survivable QOS) when we construct the system. A point-to-point self-healing scheme utilizing a conventional pre-planned backup mechanism is proposed to protect the AMT from failure. This scheme uses point-to-point pre-planned backup Root-to-Leaf Routes (RLR) as the root-to-leaf structure of an AMT. Though AMT protection via preplanned backup RLR requires no search time, duplicate paths may cause redundant bandwidth consumption. This paper also proposes a closest-node method, which can locate the minimum-length route structure during the initial design and also rebuild the AMT in the event of a network failure. To enhance the survivability of the system, we introduce two near optimal re-routing algorithms, a most-decent search algorithm, and also a predictive-decent search algorithm in order to find the minimum lost flow requirement. These near optimal schemes use search technique to guide the local optimal lost flow to the most-decent lost flow direction. The predictive way is an especially economical technique to reduce the calculation complexity of lost flow function. For the evaluation of the feasibility and performance of the new schemes, we simulate AMT restoration and the simulation results show the closest-node scheme provides superior AMT restoration compared to a system with a preplanned point-to-point backup scheme. In addition, the predictive-decent search algorithm is faster than the most-decent search one.

  • Knowledge Discovery and Self-Organizing State Space Model

    Tomoyuki HIGUCHI  Genshiro KITAGAWA  

     
    INVITED PAPER

      Vol:
    E83-D No:1
      Page(s):
    36-43

    A hierarchical structure of the statistical models involving the parametric, state space, generalized state space, and self-organizing state space models is explained. It is shown that by considering higher level modeling, it is possible to develop models quite freely and then to extract essential information from data which has been difficult to obtain due to the use of restricted models. It is also shown that by rising the level of the model, the model selection procedure which has been realized with human expertise can be performed automatically and thus the automatic processing of huge time series data becomes realistic. In other words, the hierarchical statistical modeling facilitates both automatic processing of massive time series data and a new method for knowledge discovery.

  • Experimental Characterization of the Feedback Induced Noise in Self-Pulsing Lasers

    Minoru YAMADA  Yasuyuki ISHIKAWA  Shunsuke YAMAMURA  Mitsuharu KIDU  Atsushi KANAMORI  Youichi AOKI  

     
    PAPER-Quantum Electronics

      Vol:
    E82-C No:12
      Page(s):
    2241-2247

    Generating conditions of the optical feedback noise in self-pulsing lasers were experimentally examined. The noise charcteristics were determined by changing the operating power, the feedback distance and the feedback ratio for several types of self-pulsing lasers. The idea of the effective modulation index was introduced to evaluate the generating conditions in an uniform manner based on the mode competition theory. Validity of the idea was experimentally confirmed for generation of noise.

  • A Built-in Self-Reconfigurable Scheme for 3D Mesh Arrays

    Itsuo TAKANAMI  Tadayoshi HORITA  

     
    PAPER-Fault Tolerant Computing

      Vol:
    E82-D No:12
      Page(s):
    1554-1562

    We propose a model for fault tolerant 3D processor arrays using one-and-half track switches. Spare processors are laid on the two opposite surfaces of the 3D array. The fault compensation process is performed by shifting processors on a continuous straight line (called compensation path) from a faulty processor to a spare on the surfaces. It is not allowed that compensantion paths are in the near-miss relation each other. Then, switches with only 4 states are needed to preserve the 3D mesh topology after compensating for faults. We give an algorithm in a convenient form for reconfiguring by hardware the 3D mesh arrays with faults. The algorithm can reconfigure the 3D mesh arrays in polynomial time. By computer simulation, we show the survival rates and the reliabilities of arrays which express the efficiencies of reconfiguration according to the algorithm. The reliabilities are compared with those of the model using double tracks for which the near-miss relation among compensation paths is allowed, but whose hardware overhead is almost double of that of the proposed model using one-and-half track. Finally, we design a logical circuit for hardware realization of the algorithm. Using the circuit, we can construct such a built-in self-reconfigurable 3D mesh array that the reconfiguration is done very quickly without an aid of a host computer.

  • A New Single-Clock Flip-Flop for Half-Swing Clocking

    Young-Su KWON  In-Cheol PARK  Chong-Min KYUNG  

     
    PAPER

      Vol:
    E82-A No:11
      Page(s):
    2521-2526

    A new flip-flop configuration for half-swing clocking is proposed to save total clocking power. In the proposed scheme, only NMOS's are clocked with the half-swing clock in order to make it operate without level converters or any additional logics which were used in the earlier half-swing clocking schemes. Vcc is supplied to the random logic circuits and flip-flops while Vcc/2 is supplied to the clock network and some parts of the flip-flop to reduce the power consumed in the clock network. Compared to the conventional scheme, the proposed flip-flop configuration can save the clocking power by 40%.

  • Multi-Path Backup Self-Healing Algorithm for ATM Networks

    Kiyohito YOSHIHARA  Gen HATTORI  Keizo SUGIYAMA  Sadao OBANA  

     
    PAPER

      Vol:
    E82-B No:11
      Page(s):
    1793-1800

    For backup of failed VPs (Virtual Paths) in ATM (Asynchronous Transfer Mode) networks, many self-healing algorithms have already been proposed. However, since the existing algorithms recover each failed VP with a single backup VP, a problem arises in that those algorithms cannot necessarily provide a failed VP having a higher recovery priority with a larger recovery ratio, which is the ratio of the bandwidth of a backup VP to that of a failed VP. For a solution to the problem, this paper proposes a new self-healing algorithm which recovers each failed VP with one or more backup VPs. We also evaluate its availability by comparing with an existing algorithm through simulations.

  • On the Existence and Stability of Solutions in Self-Organizing Cortical Maps

    Anke MEYER-BASE  

     
    PAPER

      Vol:
    E82-A No:9
      Page(s):
    1883-1887

    We analyze the dynamics of self-organizing cortical maps under the influence of external stimuli. We show that if the map is a contraction, then the system has a unique equilibrium which is globally asymptotically stable; consequently the system acts as a stable encoder of external input stimuli. The system converges to a fixed point representing the steady-state of the neural activity which has as an upper bound the superposition of the spatial integrals of the weight function between neighboring neurons and the stimulus autocorrelation function. The proposed theory also includes nontrivial interesting solutions.

  • A Low-Power Half-Swing Clocking Scheme for Flip-Flop with Complementary Gate and Source Drive

    Jin-Cheon KIM  Sang-Hoon LEE  Hong-June PARK  

     
    LETTER-Integrated Electronics

      Vol:
    E82-C No:9
      Page(s):
    1777-1779

    A half-swing clocking scheme with a complementary gate and source drive is proposed for a CMOS flip-flop to reduce the power consumption of the clock system by 43%, while keeping the flip-flop delay time the same as that of the conventional full-swing clocking scheme. The delay time of the preceding half stage of a flip-flop using this scheme is less than half of that using the previous half-swing clocking scheme.

  • Self-Reconstruction of 3D Mesh Arrays with 1 1/2-Track Switches by Digital Neural Circuits

    Itsuo TAKANAMI  Satoru NAKAMURA  Tadayoshi HORITA  

     
    PAPER-Configurable Computing and Fault Tolerance

      Vol:
    E82-C No:9
      Page(s):
    1678-1686

    Using Hopfield-type neural network model, we present an algorithm for reconstructing 3D mesh processor arrays using single-track switches where spare processors are laid on the six surfaces of a 3D array and show its effectiveness in terms of reconstruction rate and computing time by computer simulation. Next, we show how the algorithm can be realized by a digital neural circuit. It consists of subcircuits for finding candidate compensation paths, deciding whether the neural system reaches a stable state and at the time the system energy is minimum, and subcircuits for neurons. The subcircuit for each neuron including the other subcircuits can only be made with 16 gates and two flip-flops. Since the state transitions are done in parallel, the circuit will be able to find a set of compensation paths for a fault pattern very quickly within a time less than 1 µs. Furthermore, the hardware implementation of the algorithm leads to making a self-reconfigurable system without the aid of a host computer.

  • Self-Organizing Relationship (SOR) Network

    Takeshi YAMAKAWA  Keiichi HORIO  

     
    LETTER-Neural Networks

      Vol:
    E82-A No:8
      Page(s):
    1674-1677

    In this letter, the novel mapping network named self-organizing relationship (SOR) network, which can approximate the desired I/O relationship by employing the modified Kohonen's learning law, is proposed. In the modified Kohonen's learning law, the weight vectors are updated to be attracted to or repulsed from the input vector.

  • Generation of Wideband and Flat Supercontinuum over a 280-nm Spectral Range from a Dispersion-Flattened Optical Fiber with Normal Group-Velocity Dispersion

    Fumio FUTAMI  Yuichi TAKUSHIMA  Kazuro KIKUCHI  

     
    INVITED PAPER-Optical Fibers and Cables

      Vol:
    E82-B No:8
      Page(s):
    1265-1272

    Aiming at wideband and flat supercontinuum generation (SC) from optical fibers in the 1.55-µm wavelength region, we study both experimentally and theoretically how SC spectra are influenced by group-velocity dispersion (GVD) of fibers. In the anomalous GVD region, since the peak power of pump pulses is kept high during propagation through the fiber by the higher-order soliton effect, the Raman effect has an adverse effect to flat and wideband SC generation. In the zero GVD region, the interplay of the third-order dispersion (TOD) and the self-phase modulation splits the SC spectrum into two main components. On the other hand, in the normal GVD region, nevertheless the SC spectrum broadens wider and smoother than those in anomalous and zero GVD regions, it is still asymmetric when TOD of the fiber can not be ignored. From these results, we find that a dispersion-flattened fiber with normal GVD is the most suitable for flat and wideband SC generation. A 280-nm wide SC spectrum with the spectral-density fluctuation less than 10 dB is actually generated from such a fiber.

541-560hit(726hit)