We propose and demonstrate a directly modulated AM-VSB CATV system employing split-band and optical vestigial sideband (VSB) modulation techniques. Systems' performance can be improved by using optical VSB modulation and split-band techniques simultaneously. Our proposed directly modulated transmission system is simpler and more cost-effective than conventional externally modulated transmission system because of external modulator and complicated stimulated Brillouin scattering (SBS)-suppression method are not required.

A special group of voice application services (VASs) are promising contents for wireless as well as wireline networks. Without a designated call admission policy, VAS calls are expected to suffer from relatively high probability of blocking since they normally require better signal quality than ordinary voice calls. In this letter, we consider a prioritized call admission design in order to reduce the blocking probability of VAS calls, which makes the users feel the newly-provided VAS in belief. The VAS calls are given a priority by reserving a number of channel-processing hardwares. With the reservation, the blocking probability of prioritized VAS calls can be evidently reduced. That of ordinary calls, however, is increasing instead. This letter provides a system model that counts the blocking probabilities of VAS and ordinary calls simultaneously, and numerically examines an adequate level of the prioritization for VAS calls.

Making up an electromagnetic wave simulator based on the FEM is tried, which may run on some widely used platforms by use of Java and a single commercial tool. Since the codes and configuration files to be created for this simulator are common, one can construct the simulator running on the platforms at the same time. Using this simulator, the transmission properties of two- and three-dimensional waveguide discontinuities in optical and microwave waveguides are analyzed, the inverse problem in material constant measurement is solved, and the computed results are presented including plots of the electric field distribution.

In this paper, a non-adaptive optimal transform (NAOT) coding system is proposed. Note that the energy-invariant property in an orthogonal transformation and that the mean squared error (MSE) of a reconstructed image is proportional to the total energy of transform coefficients discarded in the coding process. The NAOT coding system is developed and proved optimal in the sense of minimum average energy loss. Basically, the proposed coding system consists of the following steps. First, obtain the average energy image block from transform image blocks. Second, sort the average energy image block in the descending order by energy where the sorted indices are recorded. Third, specify the number of coefficients, M, to be retained in the coding process. Fourth, the first M sorted indices form a set denoted as SM through which the problem of optimal feature selection in transform coding is solved. Fifth, find a fixed mask AM from set SM which is then used to select M significant transform coefficients in image blocks. Finally, the M selected coefficients are quantized and coded by the order as in SM. To verify the NAOT coding system, simulations are performed on several examples. In the simulation, the optimality and the optimal feature selection in the NAOT coding system are justified. Also, the effectiveness of the proposed SM-based selection approach is compared with the zigzag scan used in the JPEG. For fair comparison, the JPEG is modified to code only M transform coefficients. Simulation results indicate that the performance of SM-based selection approach is superior or identical to the zigzag scan in terms of PSNR. Finally, the performance comparison between the NAOT coding system and the JPEG is made. It suggests that the proposed NAOT coding system is able to trade very little PSNR for significant bit rate reduction when compared with the JPEG. Or it can be said that the JPEG wastes much bit rate to improve very little PSNR on the reconstructed image, when compared with the NAOT coding system.

This article describes a new method for converting an arbitrary topology mesh into one having subdivision connectivity. First, a base mesh is produced by applying a sequence of edge collapse operations to the original mesh with irregular connectivity. Then, the base mesh is iteratively subdivided. Each subdivided mesh is optimized to reduce its distance from the original mesh and to improve its global smoothness and compactness. A set of corresponding point pairs, which is required to compute the distance from the original mesh to the subdivided mesh, is determined by combining the initial parameterization and the multi-resolution projection. Experimental results show that the proposed method yields good performance in terms of global smoothness, small distortion, and good compactness, compared with conventional methods.

The auction is a popular way of trading. Despite of the popularity of the auction, only a small number of papers have addressed the protocol which realize the double auction. In this paper, we propose a new method of double auction which improves the algorithm of the existing double auction protocol. Our new method is based on the idea of number comparison which is realized by homomorphic encryption. The new method solves the problem of the privacy of losing bids found in the existing algorithm. The buyers and the sellers can embed a random number in their bidding information by the use of the homomorphic encryption. The players in an auction cannot get anyone else's bidding information. The new method is more efficient than the existing ones. Our new method satisfies the criteria for the auction protocol.

We have developed a three-dimensional eye movement simulator that simulates eye movement. The simulator allows us to extract the instantaneous eye movement rotation axes from clinical data sequences. It calculates the plane formed by rotation axes and displays it on an eyeball with rotation axes. It also extracts the innervations for eye muscles. The developed simulator is mainly programmed by a CG programming language, OpenGL. First, the simulator was applied to saccadic eye movement data in order to show the so-called Listing's plane on which all hypothetical rotation axes lie. Next, it was applied to clinical data sequences of two patients with benign paroxysmal positional vertigo (BPPV). Instantaneous actual rotation axes and innervations for eye muscle extracted from data sequences have special characteristics. These results are useful for the elucidation of the mechanism of vestibular symptoms, particularly vertigo.

A bi-directional WDM transmission link that changes the channel-count assigned in each direction is proposed for efficiently accommodating IP traffic which is characterized by directional volume asymmetry. A novel bi-directional optical amplifier is also proposed for overcoming the problems that arise in realizing the proposed link. The asymmetric, bi-directional, repeatered WDM transmission of 8 (total) 10 Gbit/s, 50 GHz-spaced channels over eleven 50 km spans is successfully demonstrated. The experimental results clarify that, owing to the use of the proposed bi-directional amplifier, directional asymmetry in channel-count and Rayleigh backscattering do not result in any significant performance degradation. Based upon an analysis of backscattering induced impairment, we show that the total transmission loss of 1000 dB can be supported if the span loss is 20 dB.

In this letter, we propose the Low-Density Parity-Check (LDPC) coded Orthogonal Frequency Division Multiplexing (OFDM) systems to improve the error rate performance of OFDM. We also evaluate the iterative decoding performance on both an AWGN and a frequency-selective fading channels. We show that when the energy per information bit to the noise power spectral density ratio Eb/N0 is not small, the LDPC coded OFDM (LDPC-COFDM) systems have the good error rate performance with a small number of iterations. We also show that when the Eb/N0 is small, the BER of the LDPC-COFDM systems is worse than that of the Turbo coded OFDM (TCOFDM) systems, while when the Eb/N0 is not small, the BER of the LDPC-COFDM systems is better with a small number of iterations.

This paper presents the performance modeling application of SIP-T (Session Initiation Protocol for Telephones) signaling system based on two-class priority queueing process in carrier class VoIP (Voice over IP) network. The SIP-T signaling system defined in IETF (Internet Engineering Task Force) is a mechanism that uses SIP (Session Initiation Protocol) to facilitate the interconnection of existing PSTN (Public Switched Telephone Network) with carrier class VoIP network. One of the greatest challenges in the migration from PSTN toward NGN (Next Generation Networks) is to build a carrier class VoIP network that preserves the ubiquity, quality, and reliability of PSTN services while allowing the greatest flexibility for use of new VoIP technology. Based on IETF, the SIP-T signaling system not only promises scalability, flexibility, and interoperability with PSTN but also provides call control function of MGC (Media Gateway Controller) to set up, tear down, and manage VoIP calls in carrier class VoIP network. This paper presents the two class priority queueing model, performance analysis, and simulation of SIP-T signaling system in carrier class VoIP network focused on toll by-pass or tandem by-pass of PSTN. In this paper, we analyze the average queueing length, the mean of queueing delay, and the variance of queueing delay of SIP-T signaling system that are the major performance evaluation parameters for improving QoS (Quality of Service) and system performance of MGC in carrier class VoIP network. A mathematical model of the M/G/1 queue with two-class non-preemptive priority assignment is proposed to represent SIP-T signaling system. Then, the formulae of average queueing length, queueing delay, and delay variation for the non-preemptive priority queue are expressed respectively. Several significant numerical examples of average queueing length, queueing delay, and delay variation are presented as well. Finally, the two-class priority queueing model and performance analysis of SIP-T signaling system are shown the accuracy and robustness after the comparison between theoretical estimates and simulation results.

We propose a dependency parsing model for head-final, variable word order languages. Based on the observation that each word has its own preference for its modifying distance and the preferred distance varies according to surrounding context of the word, we define a parsing model that can reflect the preference. The experimental result shows that the parser based on our model outperforms other parsers in terms of precision and recall rate.

A novel motion vector re-estimation technique for transcoding into lower spatial resolution is proposed. This technique is based on the fact that the block matching error is proportional to the complexity of the reference block with Taylor series expansion. It is shown that the motion vectors re-estimated by the proposed method are closer to optimal ones and offer better quality than those of previous techniques.

In this paper, a novel technique using proportional current feedback is proposed to improve dynamic response of digital PWM DC-DC converters. Generally, digital controllers are implemented using microprocessors or DSPs. Additional A/D converters are required to sense feedback signals. Proposed simple structure makes it feasible to integrate both A/D converter and digital controller on a single chip. System complexity and hardware cost are therefore greatly reduced. A behavioral time domain circuit model is proposed and analyzed using MATLAB. Both simulation and experimental results showed satisfactory performance to meet power requirements of microprocessors.

In this paper, we introduce an analytical model of CDMA reverse link power control based on the asymptotic theory. The effect of the SIR threshold value on the transient behavior is addressed and the optimal value of the threshold to achieve the fast convergence without oscillation is derived. In addition, the usefulness of the asymptotic analysis is confirmed by simulations.

This paper presents a novel digit-level algorithm for motion estimation (ME) and its hardware implementations. It uses the most-significant-digit-first (MSD-first) processing and on-line arithmetic ME components. A dedicated array architecture is also proposed for applications with high-throughput ME. Various fast search algorithms were presented in literatures to reduce the complexity but sacrifice the motion vector (MV) quality. Our MSD-first ME decomposes the summation of absolute differences (SAD) and comparison operations to digit level with MSD-plane first. These comparisons are interleaved into SADs to distinguish the MV as soon as possible. The algorithm precisely extracts the impossible candidates and removes their rest operations. It saves 47.4 % to 64.3 % of SAD computations in full search block matching (FSBM) ME. In the past, the high implementation cost of redundant number system prevented the practical use of on-line arithmetic. Besides, the redundant SAD removal results in irregular data flow in system-level integration. All these problems are solved by our novel architecture design. In this paper, we propose novel architecture designs to solve these problems. Besides, the architecture requires only one memory access per pixel to lower memory bandwidth by extensive data parallelism and a particular memory addressing while keeping the controller simple. A 4 4 array processor is implemented in 0.35 µm 1P4M CMOS cell library, with 2.84 ns cycle time and 1510 gates. It can support 83 M FSBM operations per second. After normalization, our implementation can support 2.67 times SAD operations per unit area (estimated in gate count) of the conventional two's complement ones. MSD-first ME can realize with other ME algorithms to improve the performance as well.

A two stage non-scan design for testability method is proposed. The first stage selects test points based on an earlier testability measure conflict. A new design for testability algorithm is proposed to select test points by a fault-oriented testability measure conflict+ in the second stage. Test points are selected in the second stage based on the hard faults after the initial ATPG run of the design for testability circuit in the preliminary stage. The new testability measure conflict+ based on conflict analysis of hard-faults in the process of test generation is introduced, which emulates most general features of sequential ATPG. The new testability measure reduces testability of a fault to the minimum D or controllability of the primary outputs, and therefore, does not need observability measure any more. Effective approximate schemes are adopted to get reasonable estimation of the testability measure. A couple of effective techniques are also adopted to accelerate the process of the proposed design for testability algorithm. Experimental results show that the proposed method gets even better results than two of the recent non-scan design for testability methods nscan and lcdft.

The size of the microscopic electron spot is an important parameter for the white-uniformity of a CRT. It changes as a function of the focus voltage and beam repulsion. This paper explains the mechanism behind this phenomenon. The model is supported by means of measurements.

The performance of a GMPLS switching architecture with or without the flush capability is studied. For this switching architecture, we propose a queueing model that includes the control plane, the switch buffer mechanism, and the flush mechanism. The flush capability is included to reduce the out-of-sequence problem due to dynamic path changes. The behavior of aggregated streams, the label-setup and release policies, and the mechanisms for efficient resource allocation are all covered. With the proposed model, one can select appropriate parameters for the label-setup policy and the label-release policy to match the traffic load and network environment. Key performance metrics, such as the label-setup rate, the switching ratio, the bandwidth utilization of the label switched path, the average delay, and the average packet loss rate, can all be evaluated via this mathematical model. Numerical results and simulations are used to verify the accuracy of the proposed queueing model. Furthermore, we adopt trace simulation to certify the applicability the proposed model. The trade-off among these performance metrics can be observed as well.

At EuroCrypt '95, Stadler, Piveteau and Camenish introduced the concept of fair blind signatures to prevent the misuse of blind signature schemes by criminals. Recently, Hwang, Lee and Lai claimed that Stadler et al.'s first fair blind signature scheme cannot meet the untraceability property of the blind signature schemes. However, this letter will demonstrate that Hwang et al.'s claim is incorrect and Stadler et al.'s first scheme still holds the untraceability property.

In this paper, we consider the problem of bearing estimation for spatially distributed sources in unknown spatially-correlated noise. Assumed that the noise covariance matrix is centro-Hermitian, a differential denoising scheme is developed. Combined it with the classic DSPE algorithm, a differential denoising estimator is formulated. Its modified version is also derived. Exactly, the differential processing is first imposed on the covariance matrix of array outputs. The resulting differential signal subspace (DSS) is then utilized to weight array outputs. The noise components orthogonal to DSS are eliminated. Based on eigenvalue decomposition of the covariance matrix of weighted array outputs, the DSPE null spectrum is constructed. The asymptotic performance of the proposed bearing estimator is evaluated in a closed form. Moreover, in order to improve the performance of bearing estimation in case of low signal-to-noise ratio, a modified differential denoising estimator is proposed. Simulation results show the effectiveness of the proposed estimators under the low SNR case. The impacts of angular spread and number of sensors are also investigated.