Optically patternable light-emitting devices based on conducting polymers were fabricated and were characterized. The cathode of the devices is made with a semitransparent-Al film, which enables to photoinduced degradation of the polymers in air. The optically patternable devices were successfully made with poly (2-methoxy-5-dodecyloxy-p-phenylene vinylene) (MDOPPV), as well as with poly (3-dodecylthiophene) (PAT12). However, optical absorption study indicated that the patterning mechanism of the MDOPPV device is considerably different from that of the PAT12 device.

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.

In the food, beverage and cosmetic industry and so on, odor sensing systems instead of human sensory test are demanded. We have developed odor sensing systems using QCM (quartz crystal microbalance) sensor array and pattern recognition method. Since the properties of the sensors depend on the gas sorption characteristics of the sensing films coated on them, the optimum films according to target odors should be selected. In this study, we tried to select sensing films appropriate for discrimination of slightly different apple flavors. The examples of typical apple flavors were prepared blending 9 compounds. The sensing films were extracted from various kinds of materials such as lipid, stationary phase material of GC (gas chromatography) and cellulose. The selection method under the condition of the small number of measurements was studied. We analyzed the data of steady-state sensor responses in terms of the Euclidean distance, and the films appropriate for apple flavor discrimination were successfully selected.

This paper describes an efficient simulation approach of a DSP controlled series-parallel resonant high frequency DC-DC power converter system. Proposed power conversion circuit simulation approach is based on a circuit equation, modeled by substituting time-varying switched resistor circuit in place of all the controllable and uncontrollable power semiconductor switching blocks of power converter circuits. An algebraic algorithm transforms the matrices of the circuit equation into the matrices of the state vector equation. Solution of state equation is by 3rd order Runge Kutta numerical integration method. Simulation results are illustrated and discussed together with experimental results.

We have proposed and demonstrated the circuit, which collectively recognizes header. Comparing with conventional schemes, the proposed circuit consists of simple structure. The proposed recognition circuit enables fast all-optical self-routing and contributes to reduce the buffer size for temporary data storage in each switch.

Channel-state-dependent (CSD) radio-resource scheduling algorithms for wireless message transport using a framed ALOHA-reservation access protocol are presented. In future wireless systems that provide Mbps-class high-speed wireless links using high frequencies, burst packet errors, which last a certain number of packets in time, would cause serious performance degradation. CSD resource scheduling algorithms utilize channel-state information for increasing overall throughput. These algorithms were comparatively evaluated in terms of average allocation plus transfer delay, average throughput, variance in throughput, and utilization of resources. Computer simulation results showed that the CSD mechanism has a good effect, especially on equal sharing (ES)-based algorithms, and also CSD-ES provides low allocation plus transfer delay, high average throughput, low variance in throughput, and efficient utilization of radio resources.

An experimental 640-Gbit/s ATM switching system is described. The switching system is scalable and quasi-non-blocking and uses hardware self-rearrangement in a three-stage network. Hardware implementation results for the switching system are presented. The switching system is fabricated using advanced 0.25-µm CMOS devices, high-density multi-chip-module (MCM) technology, and optical wavelength-division-multiplexing (WDM) interconnection technology. A scalable 80-Gbit/s switching module is fabricated in combination with a developed scalable-distributed-arbitration technique, and a WDM interconnection system that connects multiple 80-Gbit/s switching modules is developed. Using these components, an experimental 640-Gbit/s switching system is partially constructed. The 640-Gbit/s switching system will be applied to future broadband ATM networks.

A highly reliable and available network which automatically can restore itself from failures is an important concept for the future high capacity broadband networks. Self-healing algorithm, restoring the failed VPs (Virtual Paths) in the backbone ATM networks, is an indispensable technique to meet these requirements. In this paper we propose a coordination-based restoring self-healing algorithm called C-TRUS, which meets different requirements of service classes of survivability by using a simple rerouting and capacity reserving protocols. The simulation results show that the proposed algorithm can restore VPs quickly and improve the restoration time in case of multi-failures by using network resources very efficiently. Furthermore, C-TRUS outperforms the combination method in both restoration ratio and restoration time. In addition, the significant improvement of restoration ratio in the multi-failure scenario has been achieved.

An efficient location management for mobile stations plays an important role in personal communication systems. The key elements of location management are location registration and paging. In this paper, we propose the improved movement-based registration method with a selective paging scheme which enables to minimize the signaling traffic such as a paging load and a registration load. For reducing the paging load, we newly establish a paging area and analyze its performance by modeling as one dimensional random walk model with a barrier state. Further, for decreasing the registration load, we also propose a new movement-based registration scheme by using a counter and a buffer which can store the number of cell boundary crossings and the cell identification, respectively. Through numerical results, we show that our proposed movement-based registration provides a better performance than the conventional movement-based registration.

Node placement optimization in ShuffleNets is a combinatorial optimization problem. In this paper, a new heuristic node placement algorithm, called Lookahead Algorithm, is proposed. Its performance is compared with the lower bounds derived in [1], as well as some existing algorithms in the literature. Significant reduction in weighted mean hop distance hd is obtained, especially when the traffic distribution in ShuffleNets is highly skewed. Consider a ShuffleNet with 8 nodes, the hd obtained using Lookahead Algorithm is only 1.90% above the lower bound under the skewed traffic distribution (with traffic skew factor γ = 100), and 16.04% under uniform random traffic distribution.

This letter proposes an initial frame synchronization algorithm for orthogonal frequency division multiplexing (OFDM) systems. Since the proposed scheme utilizes only the cyclic prefix and the phase shift of the demodulated data without the aid of any known signals, it can be applied not only at the beginning of data transmission but also at any instant during transmission. The performance of the proposed algorithm is confirmed by computer simulation for QPSK, 8-PSK, and 16-QAM systems.

This paper presents a new method for statistical modelling of prosody control in speech synthesis. The proposed method, which is referred to as Constrained Tree Regression (CTR), can make suitable representation of complex effects of control factors for prosody with a moderate amount of learning data. It is based on recursive splits of predictor variable spaces and partial imposition of constraints of linear independence among predictor variables. It incorporates both linear and tree regressions with categorical predictor variables, which have been conventionally used for prosody control, and extends them to more general models. In addition, a hierarchical error function is presented to consider hierarchical structure in prosody control. This new method is applied to modelling of speech segmental duration. Experimental results show that better duration models are obtained by using the proposed regression method compared with linear and tree regressions using the same number of free parameters. It is also shown that the hierarchical structure of phoneme and syllable durations can be represented efficiently using the hierarchical error function.

Photocarrier transport of regiorandom poly(3-hexylthiophene) P3HT in ITO/P3HT/Al sandwich cell configuration has been investigated by means of Time-of-Flight technique. Characteristics of Schottky diode and the magnitude of hole mobility have been found to be affected by impurities involved during the synthesis. The hole mobility in regiorandom P3HT at room temperature has been estimated to be 2.4 10-5 and 2.6 10-4 cm2/V. s before and after the removal of ferric ions, respectively, at a field of 5.0105 V/cm. Field dependencies of mobility before and after purification show unique feature and have been discussed in terms of the disorder model.

We have developed a polymer tunable wavelength filter using cross-linked silicone as a waveguide material for wavelength division multiplexing (WDM) systems. The filter operated with a low insertion loss of 3.6-4.1 dB, a low crosstalk of < -30 dB, and a wide tuning range of 10 nm in the 20 to 80C temperature region without any changes in the spectral profile. We investigated the optical characteristics of the 32-ch WDM signals transmitted through the filter. We realized a stable filtering operation by introducing a feedback system. We also applied the filter to a WDM/SCM (subcarrier multiplexing) broadcast-and-select LAN system. We were able to realize a LAN system which operated at 6 Mbit/s and had 3200 channels by using 10-wavelength WDM signal. This suggests that our polymer tunable wavelength filter is suitable for practical use.

The emergence of nomadic applications have recently generated a lot of interest in wireless network infrastructures which support multimedia services. In this paper, we propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e. g. ATM or Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy bandwidth requirement for quality-of-service (QoS) constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.

Thin films of carbon (C)-sulfur (S) compound were formed by plasma CVD (PCVD) at the special chemical condition. The reactor has a parallel plate electrode system and was operated at a discharge frequency of 13.56 MHz with using a mixture gas of argon (Ar), methane (CH4) and SF6. The deposition was performed on a substrate placed on the grounded electrode. Atomic composition of the film was observed to depend on the gas mixture ratio. The sulfur atom density was increased up to 30% with using a mixture gas at a pressure of 0.1 Torr and at a flow rate of 20, 20 and 50 SCCM for Ar, CH4 and SF6, respectively. It was expected that the C-S compounds were deposited under the condition of F atom elimination by forming HF.

In this paper, a method of fusing ground-based laser range image and CCD images for the reconstruction of textured 3D urban object is proposed. An acquisition system is developed to capture laser range image and CCD images simultaneously from the same platform. A registration method is developed using both laser range and CCD images in a coarse-to-fine process. Laser range images are registered with an assumption on sensor's setup, which aims at robustly detecting an initial configuration between the sensor's coordinate system of two views. CCD images are matched to refine the accuracy of the initial transformation, which might be degraded by improper sensor setup, unreliable feature extraction, or limited by low spatial resolution of laser range image. Textured 3D model is generated using planar faces for vertical walls and triangular cells for ground surface, trees and bushes. Through an outdoor experiment of reconstructing a building using six views of laser range and CCD images, it is demonstrated that textured 3D model of urban objects can be generated in an automated manner.

We developed a new water repellent coating consisting of PTFE particles dispersed in PVDF resin. This coating exhibited a contact angle of 150 degrees. By ice accreting test, the intensity of reflected microwave on the water-repellent coated plate did not decrease, whereas that on uncoated one decreased.

In conventional methods for detecting vanishing points and vanishing lines, the observed feature points are clustered into collections that represent different lines. The multiple lines are then detected and the vanishing points are detected as points of intersection of the lines. The vanishing line is then detected based on the points of intersection. However, for the purpose of optimization, these processes should be integrated and be achieved simultaneously. In the present paper, we assume that the observed noise model for the feature points is a two-dimensional Gaussian mixture and define the likelihood function, including obvious vanishing points and a vanishing line parameters. As a result, the above described simultaneous detection can be formulated as a maximum likelihood estimation problem. In addition, an iterative computation method for achieving this estimation is proposed based on the EM (Expectation Maximization) algorithm. The proposed method involves new techniques by which stable convergence is achieved and computational cost is reduced. The effectiveness of the proposed method that includes these techniques can be confirmed by computer simulations and real images.

Short-circuit photocurrents (ISC) utilizing surface plasmon polariton (SPP) excitation were investigated for the merocyanine (MC) LB film photoelectric device. The device has a prism/MgF2/Al/MC LB film/Ag structure. In the attenuated total reflection (ATR) configuration, SPPs were resonantly excited at the interfaces between MgF2 and Al (MgF2/Al) and between Ag and air (Ag/air). The thickness and the dielectric constants of the layers were evaluated from the ATR measurements. Short-circuit photocurrents, ISCs, as a function of the incident angle of the laser beam were observed simultaneously during the ATR measurements. In the ISC curves, large and small peaks were observed, and the peak angles of the ISC almost corresponded to the dip angles of the ATR curves due to the SPP excitations. Electric fields and optical absorptions in the cell were calculated using the dielectric constants and the film thickness obtained from the ATR measurements. The calculated absorption in the MC layer as a function of the incident angle corresponded to the ISC curve. It was thought that the optical absorption in the MC layer affected directly to the profile of the ISC. Furthermore, the calculated absorption in the cell with the prism and the MgF2 layer exhibited much larger than that of the cell without them. It was estimated that the photocurrents were enhanced by the excitation of SPPs in the ATR configuration.