We can model embedded systems as hybrid systems. Moreover, they are distributed and real-time systems. Therefore, it is important to specify and verify randomness and soft real-time properties. For the purpose of system verification, we formally define probabilistic linear hybrid automaton and its symbolic reachability analysis method. It can describe uncertainties and soft real-time characteristics.

In this paper, we propose a new multimodal interaction description language, MIML (Multimodal Interaction Markup Language), which defines dialogue patterns between human and various types of interactive agents. The feature of this language is three-layered description of agent-based interactive systems. The high-level description is a task definition that can easily construct typical agent-based interactive task control information. The middle-level description is an interaction description that defines agent's behavior and user's input at the granularity of dialogue segment. The low-level description is a platform dependent description that can override the pre-defined function in the interaction description. The connection between task-level and interaction-level is realized by generation of interaction description templates from the task level description. The connection between interaction-level and platform-level is realized by a binding mechanism of XML. As a result of the comparison with other languages, MIML has advantages in high-level interaction description, modality extensibility and compatibility with standardized technologies.

Access selection in future multiple radio access environments is considered in this paper from a new perspective, that of the consumer. A model is proposed for the automatic acquisition of user preferences to assist in access selection decision making. The proposed approach uses a two-level Bayesian C-Metanetwork that models individual user preferences in terms of affordable cost, acceptable level of quality of service and reputation of the access networks. User preferences under different contexts, such as leisure and business, are also considered. The model also adapts to the change of user preferences over time. A simulator has been developed to evaluate the proposed model and the simulation results are promising in terms of the proportion of correct preference predictions after a small number of training samples.

To cut down the sidelobe level of radiation pattern, a novel adaptive algorithm is proposed for electronic steering parasitic antenna. The composite objective function in this algorithm takes both directivity and sidelobe level of pattern into account, and the steepest gradient algorithm is selected to search the optimum value of reactive load. Simulations are carried out to validate the algorithm, simulated results show that the levels of sidelobe are both below -4 dB in different beamforming cases, and the front to back ratios are better than 10 dB.

A block-matching-based self-organizing map (BMSOM) is presented. Finding a winner is carried out for each block, which is a set of neurons arranged in square. The proposed learning process updates the reference vectors of all of the neurons in a winner block. Then, the degrees of vector modifications are mainly controlled by the size (i.e., the number of neurons) of the winner block. To prevent a single cluster with neurons from splitting into some disjointed clusters, the restriction of the block size is imposed in the beginning of learning. At the main stage, this restriction is canceled. In BMSOM learning, the size of a winner block does not always decrease monotonically. The formula used to update the reference vectors is basically uncontrolled by time. Therefore, even if a map is in a nonstationary environment, training the map is probably pursued without interruption to adjust time-controlled parameters such as learning rate. Numerical results demonstrate that the BMSOM makes it possible to improve the plasticity of maps in a nonstationary environment and incremental learning.

Timing optimization is an important goal of global routing in deep submicron era. To guarantee the timing performance of the circuit, merely adopting topology optimization becomes inadequate. In this paper, we present an efficient timing-driven global routing algorithm with buffer insertion. Our approach is capable of applying topological-based timing optimization and buffer insertion simultaneously with routablity considerations. Compared with previous works, we efficiently solve the timing issues under a limited buffer usage. The experimental results have demonstrated significant delay improvement within short runtime with very small number of buffers inserted.

In our previous work, the hyper H∞ filter is developed for tracking of unknown time-varying systems. Additionally, a fast algorithm, called the fast H∞ filter, of the hyper H∞ filter is derived on condition that the observation matrix has a shifting property. This algorithm has a computational complexity of O(N) where N is the dimension of the state vector. However, there still remains a possibility of deriving alternative forms of the hyper H∞ filter. In this work, a fast J-unitary form of the hyper H∞ filter is derived, providing a new H∞ fast algorithm, called the J-fast H∞ filter. The J-fast H∞ filter possesses a computational complexity of O(N), and the resulting algorithm is very amenable to parallel processing. The validity and performance of the derived algorithm are confirmed by computer simulations.

This paper presents a new technique for automatically synthesizing human walking motion. In the technique, a set of fundamental motion units called motion primitives is defined and each primitive is modeled statistically from motion capture data using a hidden semi-Markov model (HSMM), which is a hidden Markov model (HMM) with explicit state duration probability distributions. The mean parameter for the probability distribution function of HSMM is assumed to be given by a function of factors that control the walking pace and stride length, and a training algorithm, called factor adaptive training, is derived based on the EM algorithm. A parameter generation algorithm from motion primitive HSMMs with given control factors is also described. Experimental results for generating walking motion are presented when the walking pace and stride length are changed. The results show that the proposing technique can generate smooth and realistic motion, which are not included in the motion capture data, without the need for smoothing or interpolation.

We developed material and process technologies concerned to DDF, which is formed on MgO surface around the inter-pixel gap to prevent vertical crosstalk discharge in stripe rib structure. First we tried with thin film deposition and lift-off patterning to find Al2O3 and TiO2 are both available for DDF material. Next we tried with thick film printing in favor of mass productivity for large size PDPs. In case DDF included PbO glass, we met serious hardship in generating discharge. The problem was perfectly solved by having thick film DDF composed of 100 nm sized Al2O3 grains without glass component. Its γi was about 1/5 that of MgO, suggesting that the thick film DDF is almost compatible with thin film Al2O3 in electron emission characteristics. Such very small grain size contributes to DDF transparency, which is excellently high. In addition to it, such DDF is equipped with cushioning effect to prevent dot defects caused by rib breakage. Furthermore the DDF functions as getter during panel exhaustion to bring deep blue color by promoting deoxidization of blue phosphor provided that its volume is small enough. Transparent DDF may be rather better than black one with respect to bright room contrast ratio, not to mention to avoiding terrible sparking discharge. Thus material and process technologies for DDF have been almost fixed in success.

We had recently measured a chromatic dispersion of optical fiber and a time delay of chirped fiber grating based on a bidirectional modulation of an optical intensity modulator. In this paper, we analyze characteristics of the chromatic dispersion measurement method using a bidirectional modulation of an optical intensity modulator, and give a detailed explanation about the selection of measurement setup parameters to achieve an accurate measurement. We also propose a modified measurement system to decrease relative intensity noise caused by the bidirectional transmission through a device under test.

This letter develops convergence analysis of normalized sign-sign algorithm (NSSA) for FIR-type adaptive filters, based on an assumption that filter tap weights are Gaussian distributed. We derive a set of difference equations for theoretically calculating transient behavior of filter convergence, when the filter input is a White & Gaussian process. For a colored Gaussian input and a large number of tap weights, approximate difference equations are also proposed. Experiment with simulations and theoretical calculations of filter convergence demonstrates good agreement between simulations and theory, proving the validity of the analysis.

The performance of avalanche photodiodes with deep guard rings for Geiger mode operation is studied. The electric field distribution is calculated using the finite element method and the carrier multiplication characteristic is calculated along typical lines in the device. The nonlinear dependence of the ionization rates on the electric field strength can make a guard ring less effective in Geiger mode operation. The maximum single photon detection efficiency that can be obtained without breakdown at the guard ring is calculated for several structure parameters. It is shown that the single photon detection efficiency strongly depends on the guard ring design.

The next-generation wireless networks will bring users with Software Defined Radio (SDR) terminals seamless mobility and ubiquitous computing through heterogeneous networks. This paper proposes a soft-prioritization based system selection algorithm performed by SDR terminal and investigates the effectiveness of the soft-prioritization based system selection by using a concrete simulation model. To maximize the quality of service (QoS), wireless communication systems are prioritized on the basis of criteria for system selection such as data rate, channel quality and cost, and should be dynamically changed. However, frequent inter-system handovers based on hard-prioritization are undesirable in view of interrupting and dropping, particularly for real-time traffic and managing channel capacities. Wireless communication systems are softly prioritized in the soft-prioritization based system selection algorithm, and therefore inter-system handovers between systems with the same priority aren't initiated. To elucidate the validity of the soft-prioritization based system selection algorithm, a system simulation model consisting of five wireless communication systems is employed. Simulation results confirm that the soft-prioritization system selection algorithm offers higher performance in terms of the number of inter-system handovers and throughput of best effort traffic.

This paper proposes two space-time joint channel parameter estimation and signal detection algorithms for downlink DS-CDMA systems with multiple-input-multiple-output (MIMO) wireless multipath fading channels. The proposed algorithms initially use the space-time MUSIC to estimate the DOA-delays of the multipath channel. Based on these estimated DOA-delays, a space-time channel decoupler is developed to decompose the multipath downlink channel into a set of independent parallel subchannels. The fading amplitudes of the multipath can then be estimated from the eigen space of the output of the space-time channel decoupler. With these estimated channel parameters, signal detection is carried out by a maximal ratio combiner on a pathwise basis. Computer simulations show that the proposed algorithms outperform the conventional space-time RAKE receiver while having the similar performance compared with the space-time minimum mean square error receiver.

It is often observed that the operation of the digitally controlled dc-dc power converter becomes unstable when the relatively large integral coefficient is used to extend the regulation range of the output voltage to handle variations in the input voltage and load. This paper presents a novel digital controller with static model reference for switching dc-dc power converters to improve the performance characteristics and discusses its design-oriented analysis in the steady-state characteristics. It is clarified theoretically and experimentally that using the static model reference, the wide regulation range of the output voltage to handle variations in the input voltage and load current can be achieved with the appropriate small integral coefficient in the digital P-I-D controller. Therefore, since the integral coefficient is selected to cover the maximum instantaneous variation value of the static reference model, the integral coefficient is small and the operation is always stable.

In 2002, Zhu et al. proposed a password-based authenticated key exchange protocol based on RSA. Zhu et al. claimed the protocol is efficient for the low-power devices in wireless networks. Unfortunately, Yeh et al. pointed out that Zhu et al.'s protocol was weak against undetectable on-line password guessing attack. Not only that, Zhu et al.'s protocol does not achieve explicit key authentication. At the same time, Yeh et al. proposed an improved method. However, in this paper, we shall point out that Yeh et al.'s improvement is vulnerable to the off-line password guessing attack. At the same time, we shall propose a solution to resist the above attack.

This paper proposes a backlight module which drives multiple cold-cathode fluorescent lamps (CCFLs) with a current mirror technique to equalize the driving current for each lamp. We first adopt a half-bridge parallel-resonant inverter as the main circuit and use a single-input, multiple-output transformer to drive the multi-CCFLs. Next, we introduce current-mirror circuits to create a new current-sharing circuit, in which its current reference node and the parallel-connected multi-load nodes are used to accurately equalize all CCFLs' driving current. This will balance each lamp's brightness and, consequently, improve the picture display quality of the related liquid crystal display (LCD). This paper details the design concept for each component value with the assistance of an actual design example. The results of the example are examined with its actual measurements, which consequently verify the correctness of the proposed control strategy.

Volume Graphics Clusters (VG Clusters) have proven to be efficient in a wide range of visualization applications and have also shown promise in some other applications where the image composition device could be fully utilized. The main differentiating feature from other graphics clusters is a specialized image composition device, commercially available as the MPC Image Compositor, which enables the building of do-it-yourself VG Clusters. Although this device is highly scalable, the unidirectional composition flow limits the data subdivision to the quantity of physically available rendering nodes. In addition, the limited buffer memory limits the maximum capable image composition size, therefore limiting its use in large-scale data visualization and high-resolution visualization. To overcome these limitations, we propose and evaluate an image composition mechanism in which additional hardware is used for assisting the image composition process. Because of the synergistic use of two distinct image composition hardware devices we named it "Hybrid Image Composition". Some encouraging results were obtained showing the effectiveness of this solution in improving the VG Cluster 's potential. A low-cost parallel port based hardware barrier is also presented as an efficient method for further enhancing this kind of small-scale VG Cluster. Moreover, this solution has proven to be especially useful in clusters built using low-speed networks, such as Fast Ethernet, which are still in common use.

Driving methods for TFT-OLEDs are explained with their features and classified from the viewpoints of grayscale methods and uniformizing methods. This classification leads us to a novel proposal using time ratio grayscale and current uniformization. This driving method maintains current uniformity and simultaneously overcomes charging shortage of the pixel circuit for low grayscale levels and current variation due to the shift of operating points. Tolerance toward degraded characteristics, linearity of grayscale and luminance uniformity against degraded characteristics are confirmed using circuit simulation.

A polarization-independent liquid crystal (LC) grating with a microscale LC molecular alignment pattern is proposed. The microscale LC alignment pattern is achieved using a microrubbing technique. The optical properties of the proposed LC grating are theoretically discussed in detail using Jones matrix method. Optimum condition for obtaining maximum +1st or -1st diffraction efficiencies is derived. The diffraction efficiency of the LC grating is measured and the diffraction efficiency characteristics are compared with the theoretical result. Furthermore, the dependence of the polarization direction of the incident light on the diffraction efficiency is discussed.