A hidden Markov model (HMM)-based parameter estimation scheme is proposed for wideband speech recovery. In each Markov state, the estimation efficiency is improved using a new mapping function derived from the weighted least squares of vector deviations. The experimental results reveal that the performance of the proposed scheme is superior to that combining the HMM and Gaussian mixture model (GMM).

The most obvious architectural solution for high-speed fuzzy inference is to exploit temporal parallelism and spatial parallelism inherited in a fuzzy inference execution. However, in fact, the active rules in each fuzzy inference execution are often only a small part of the total rules. In this paper, we present a new architecture that uses less hardware resources by discarding non-active rules in the earlier pipeline stage. Compared with previous work, implementation data show that the proposed architecture achieves very good results in terms of the inference speed and the chip area.

This paper presents a pseudo glottal excitation model for the type of linear prediction vocoders with speech being coded at 1.6 kbps. While unvoiced speech and silence intervals are processed with a stochastic codebook of 512 entries, a glottal codebook with 32 entries for voiced excitation is used to describe the glottal phase characteristics. Steps of formulating the pseudo glottal excitation for one pitch period consist of 1) applying a polynomial model to simulate the low-frequency constituent of the residual, 2) inserting a magnitude-adjustable pulse sequence to characterize the main excitation, and 3) introducing turbulent noise in series with the resulting excitation. Procedures are described for codebook construction in addition to analysis and synthesis of the pseudo glottal excitation. Results in a mean opinion score (MOS) test show that the quality produced by the proposed coder is almost as good as that by 4.8 kbps CELP coder for male utterances, but the quality for female utterances is yet somewhat inferior.

This study presents an adaptive quantization index modulation scheme applicable on a small audio segment, which in turn allows the watermarking technique to withstand time-shifting and cropping attacks. The exploitation of auditory masking further ensures the robustness and imperceptibility of the embedded watermark. Experimental results confirmed the efficacy of this scheme against common signal processing attacks.

An echo-hiding scheme is presented to detect the pitch variation due to playback speed modification. The inserted time-spread echo is obtained by convolving the highpass filtered audio with a gain-controlled pseudo noise sequence. The perceptual evaluation confirms that the embedded echo is virtually imperceptible. Compared with the Fourier magnitude modulation, the proposed scheme attains better detection rates.

The relative window method provides quantitative crosstalk delay degradation for the post-layout timing analysis in deep sub-micron VLSI design. However, to the best of our knowledge, the relative window method has not been applied to the crosstalk minimization in gridded channel routing problem. Most conventional crosstalk optimizers only use the coupling length to estimate the crosstalk. In this paper, we present a post-layout timing driven crosstalk optimizer based on the relative window method. According to the relative signal arrival time and the coupling length, we define a delay degradation graph to describe the crosstalks between nets in a routing solution. Our optimization goal is to maximize the time slack by iteratively improving the delay degradation graph without increasing the channel height. Benchmark data consistently show that our post-layout timing driven crosstalk optimizer can further improve the routing solution obtained by a conventional crosstalk optimizer.

With the advent of deep sub-micron era, there is a demand to consider the design closure problem in high-level synthesis. It is well known that the slack is an effective means of tolerating the uncertainties in operation delays. Previous work ever attempted to increase the usable slack based on a given initial schedule. Instead of the post-processing approach, this paper is the first attempt to the simultaneous application of operation scheduling and slack optimization. We use a 0-1 integer linear programming (0-1 ILP) approach to formally formulate the problem. Under the design constraints (timing and resource), our approach is applicable to two different objective functions: the maximization of the total usable slack and the maximization of the number of non-zero slack operations. Compared with previous work, our approach has the following two advantages: first, our approach guarantees the optimality; second, our approach is more suitable for the design space exploration.

Because dielectrics between active layers have low thermal conductivities, there is a demand to reduce the temperature increase in three-dimensional integrated circuits (3D ICs). This paper demonstrates that, in the design of 3D ICs, different layer assignments often lead to different temperature increases. Based on this observation, we are motivated to perform temperature-aware layer assignment. Our work includes two parts. Firstly, an integer linear programming (ILP) approach that guarantees a minimum temperature increase is proposed. Secondly, a polynomial-time heuristic algorithm that reduces the temperature increase is proposed. Compared with the previous work, which does not take the temperature increase into account, the experimental results show that both our ILP approach and our heuristic algorithm produce a significant reduction in the temperature increase with a very small area overhead.

In conventional preamble based channel estimation in OFDM/offset QAM (OFDM/OQAM) system, both the even index subcarriers and the odd index subcarriers are with identical value selected from { 1 } respectively to avoid inter-carrier interference (ICI), if and only if channel frequency response in neighbor few subcarriers remain invariable. However, it requires larger coherent bandwidth. In this paper, we propose an effective preamble design with ICI cancellation for channel estimation in OFDM/OQAM system. With this structure, we only utilize even (or odd) index of subcarriers as reference signal to avoid ICI, and then the channel information of remaining subcarriers can be estimated by the interpolation approach. Based on the sampling theorem, the mean square error (MSE) performance of the proposed preamble design is analyzed, where channel estimation performance is same for all subcarriers. Simulation and analytical results demonstrate that the proposed preamble design with ICI cancellation method outperforms the conventional one in term of channel estimation accuracy in OFDM/OQAM system.

Although much research effort has been devoted to the minimization of total power consumption caused by the clock tree, no attention has been paid to the minimization of the peak current caused by it. In this paper, we propose an opposite-phase clock scheme to reduce the peak current incurred by the clock tree. Our basic idea is to balance the charging and discharging activities. According to the output operation, the clock buffers that transit simultaneously are divided into two groups: half of the clock buffers transit at the same phase of the clock source, while the other half transit at the opposite phase of the clock source. As a consequence, the opposite-phase clock scheme significantly reduces the peak current caused by the clock tree. Experimental data show that our approach can be applied at different design stages in the existing design flow.

At the behavioral level, large power savings are possible by shutting down unused operations, which is commonly referred to as power management. However, operation scheduling has a significant impact on the potential for power saving via power management. In this paper, we present an integer linear programming (ILP) model to formally formulate the simultaneous application of operation scheduling and power management in high level synthesis. Our objective is to maximize the power saving under both the timing constraints and the resource constraints. Note that our approach guarantees solving the problem optimally. Compared with previous work, experimental data consistently show that our approach has significant relative improvement in the power savings.