In this paper, a modified neural network approach called the Guided Neural Network is proposed for the longitudinal dynamics identification of a vehicle using the well-known gradient descent algorithm. The main contribution of this paper is to take account of the known information about the system in identification and to enhance the convergence of the identification errors. In this approach, the identification is performed in two stages. First, the Guiding Network is utilized to obtain an approximate dynamic characteristics from the known information such as nonlinear models or expert's experiences. Then the errors between the plant and Guiding Network are compensated using the Compensating Network with the gradient descent algorithm. With this approach, the convergence speed of the identification error can be enhanced and more accurate dynamic model can be obtained. The proposed approach is applied to the longitudinal dynamics identification of a vehicle and the resultant performance enhancement is given.

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.

This paper presents a universally verifiable Mix-net where the amount of work done by a verifier is independent of the number of mix-servers. Furthermore, the computational task of each mix-server is constant with regard to the number of mix-servers except for some negligible tasks like computing hash function when no disruption occurs. The scheme also provides robustness.

We demonstrate unique dye-doping method to realize organic light emitting diodes (OLED) with high efficiency, high brightness and pure red emission. In this study, we used 5,10,15,20 tetraphenyl -21H,23H-porphine (TPP) as emitting dopant into 8-hydroxyquinoline aluminum (Alq3) emissive layer. To improve turn-on voltage and emission characteristics, a sufficient amount of 4-(dicyano methylene) -2-methyl -6-(p-dimethyl aminostyryl) -4H-pyran (DCM) was added to the TPP doped Alq3 emissive layer. The mechanisms and the emission characteristics of the co-doped EL device are discussed using energy band diagram of the materials used in the device.

In this study, we prepared red organic light- emitting-diode (OLED) with a fluorescent dye(Sq)-doped and inserted 1,3-bis (5-p-t-butylphenyl)-1,3,4-oxadiazol-2-yl) benzene (OXD7) or/and tris (8-hydroxyquinoline) aluminum (Alq3) layers between emission layer and cathode in order to increase electroluminescent (EL) efficiency. This inserting effect has been observed and EL mechanism characteristics have been examined. The hole transport layer was N,N'-diphenyl-N, N'bis-(3-methylphenyl)-1,1'diphenyl-4,4'-diamine (TPD); the host material of emission layer was Alq3; the guest material of emission layer was Sq. When Alq3 was inserted between the emission layer and the cathode, emission efficiency increased. Highly pure red emission, however, was not attaina ble with Alq3. On the other hand, the insertion of OXD7 between the two layers blocked and accumulated holes. Because of its increasing recombination probability of electron and hole, luminance characteristics and emission efficiency were improved with holding highly pure red color.

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.

We have developed a map-based approach that enables us to efficiently extract information about man-made objects, such as buildings, from aerial images. An image is matched with a corresponding map in order to estimate the object information in the image (i. e. , presence, location, shape, size, kind, and surroundings). This approach is characterized by using a figure contained in a map as an object model for a top-down (model-driven) analysis of an object in the aerial image. We determined the principal steps of the map-based approach needed to extract object information and update a map. These steps were then applied to obtain the locations of missing buildings and the heights of existing buildings. The extraction results of experiments using aerial images of Kobe City (taken after the 1995 earthquake) show that the approach is effective for automatically extracting building information from aerial images and for rapidly updating map data.

In this paper we deal with the problem of calibrating a rotating and zooming camera, without 3D pattern, whose internal calibration parameters change frame by frame. First, we theoretically show the existence of the calibration parameters up to an orthogonal transformation under the assumption that the skew of the camera is zero. Auto-calibration becomes possible by analyzing inter-image homographies which can be obtained from the matches in images of the same scene, or through direct nonlinear iteration. In general, at least four homographies are needed for auto-calibration. When we further assume that the aspect ratio is known and the principal point is fixed during the sequence then one homography yields camera parameters, and when the aspect ratio is assumed to be unknown with fixed principal point then two homographies are enough. In the case of a fixed principal point, we suggest a method for obtaining the calibration parameters by searching the space of the principal point. If this is not the case, then nonlinear iteration is applied. The algorithm is implemented and validated on several sets of synthetic data. Also experimental results for real images are given.

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.

Given a set of still images taken from a hand-held camera, we present a fast method for mosaicing them into a single blended picture. We design time- and memory- efficient still image mosaicing algorithms based on geometric point feature matchings that can handle both arbitrary rotations and large zoom factors. We discuss extensions of the methodology to related problems like the recovering of the epipolar geometry for 3d reconstruction and object recognition tasks.

We have reviewed recent progress on arrayed waveguide gratings for DWDM applications. AWGs can be used to realize not only mux/demux filters with various channel spacings, but also highly integrated optical components.

As the clock skew is one of the major constraints for high speed synchronous ICs, it must be minimized in order to obtain high performance. But clock skew minimization may increase the total wire length; therefore, clock routing is performed within the given skew bound. Clock routing under the specified skew bound can decrease the total wire length. A new efficient algorithm for bounded clock skew routing using link-edge insertion is proposed in this paper. It satisfies the given skew bound and prevents the total wire length from increasing. Not only the total wire length and delay time minimization algorithm using the new merging point relocation method but also the clock skew reduction algorithm using link-edge insertion technique for a pair of nodes whose delay difference is large is proposed. The proposed algorithm constructs a new clock routing topology which is a generalized graph model, while most previous methods use only tree-structured routing topology. A new cost function is designed in order to select two nodes for link-edge addition. Using this cost function, delay difference or clock skew is reduced by connecting two nodes whose delay difference is large and distance is small. Furthermore, routing topology construction and wire sizing algorithm is used to reduce the clock delay. The proposed algorithm is implemented in C programming language. The experimental results show that the total wire length can be reduced under the given skew bound.

We propose a novel Bragg grating filter synthesis method using a Fourier transform of the target scattering matrix. Multiple scattering processes are taken into account by iteration to improve the synthesis accuracy.

We have developed spectral separation devices for processing femtosecond pulses. These devices are based on an optical coupler structure with fiber gratings. In a computer simulation, we confirmed that these devices could extract <1 nm bandwidth light with 80% efficiency. We fabricated the spectral separation devices using single mode fibers and highly Ge-doped fibers. These devices successfully extracted narrow spectral light of 0.3 nm bandwidth with 37% efficiency from femtosecond pulses of 40 nm bandwidth. We also fabricated 2-channel spectral separation devices, which could extract the light from each grating channel.

A generalized class of consecutive-k-out-of-n:G systems, referred to as Con/k*/n:G systems, is studied. A Con/k*/n:G system has n ordered components and is good if and only if ki good consecutive components that originate at component i are all good, where ki is a function of i. Theorem 1 gives an O(n) time equation to compute the reliability of a linear system and Theorem 2 gives an O(n2) time equation for a circular system. A distributed computing system with a linear (ring) topology is an example of such system. This application is very important, since for other classes of topologies, such as general graphs, planar graphs, series-parallel graphs, tree graphs, and star graphs, this problem has been proven to be NP-hard.

A 160 GHz colliding-pulse mode-locked laser diode (CPM-LD) was stabilized by injection of a stable master laser pulse train repeated at a 16th-subharmonic-frequency (9.873 GHz) of the CPM-LD's mode-locking frequency. Synchroscan steak camera measurements revealed a clear pulse train with 16-times repetition frequency of the master laser pulse train for the stabilized CPM-LD output, indicating that CPM-LD output was synchronized to the master laser and that the timing jitter was also reduced. The timing jitter of the stabilized CPM-LD was quantitatively evaluated by an all-optical down converting technique using the nonlinearity of optical fiber. This technique is simple and has a wider bandwidth in comparison to a conventional technique, making it possible to accurately measure the phase noise of ultrafast optical pulse train when its repetition frequency exceeds 100 GHz. The electrical power spectra measurements indicated that the CPM-LD's mode-locking frequency was exactly locked by the injection of the master laser pulse train and that the timing jitter decreased as the injection power increased. The timing jitter was reduced from 2.2 ps in free running operation to 0.26 ps at an injection power of 57 mW, comparable to that of the master laser (0.21 ps).

We describe the fabrication method and characteristics of hybrid external cavity lasers composed of a spot-size converter integrated LD (SS-LD) and a UV written Bragg grating in a planar lightwave circuit (PLC) on a Si substrate. The SS-LD is passively aligned on a Si platform formed in the PLC, and the UV grating is created in the PLC with ArF laser irradiation through a phase mask. This structure enables us to fabricate a stable single-mode laser with a precisely controllable oscillation wavelength. By using the above techniques, we obtained a threshold current of 7-8 mA and a side mode suppression of 37 dB for an external cavity laser operating at 1.3 µm. Moreover, we successfully demonstrated a four-channel external cavity laser with a wavelength interval of 2 nm 0.1 nm by integrating 4 SS-LDs on a PLC and controlling the Bragg wavelengths with ArF laser irradiation without a phase mask.

The conventional back-propagation algorithm cannot be applied to networks of units having hard-limiting output functions, because these functions cannot be differentiated. In this paper, a gradient descent algorithm suitable for training multilayer feedforward networks of units having hard-limiting output functions, is presented. In order to get a differentiable output function for a hard-limiting unit, we utilized that if the bias of a unit in such a network is a random variable with smooth distribution function, the probability of the unit's output being in a particular state is a continuously differentiable function of the unit's inputs. Three simulation results are given, which show that the performance of this algorithm is similar to that of the conventional back-propagation.

In this paper, a new network structure called generalized Hierarchical Completely-Connected networks (HCCs) is proposed, and its properties and features are evaluated. Simple routing strategies for HCCs are also developed for shortest-paths routing algorithms. A set of HCCs constructed by the proposed method includes some conventional hierarchical networks, then it is called generalized one. The construction of an HCC starts from a basic block (a level-1 block) which consists of n nodes of constant degree. Then a level-h block for h 2 is constructed recursively by interconnecting any pair of macro nodes (n level-(h-1) blocks) completely. An HCC has a constant node-degree regardless of an increase in its size (the number of nodes). Furthermore, since an HCC has a hierarchically structured topology and the feature of uniformity, a wide variety of inter-cluster connections is possible. Evaluation results show that an HCC is suitable for very large computer systems.

A theoretical study on high slope-efficiency phase-shifted DFB laser diodes is presented. We have proposed a new grating structure called asymmetrically-pitch-modulated (APM) grating, and calculated its slope- efficiency and single-mode-yield. In order to take into account the modulated grating period; we have developed an F-matrix which directly includes a chirped grating structure. APM phase-shifted DFB laser diodes consist of a uniform grating in one half section of the cavity and a chirped grating in the other half. This structure causes asymmetrical field distribution inside the cavity and the optical output power from one facet is larger than that from the other facet. According to the simulation results, when the normalized coupling coefficient κ L is 3.0, the front-to-rear output power ratio is 2.6, while the single-mode-yield remains at 100%, and simultaneously the slope-efficiency improvement becomes 65% better than that of ordinary quarter-wave phase-shifted DFB lasers of the same κ L value.