New design method for digital servo systems with number limited and bounded inputs is proposed. Most important point in this paper is a new approach for on-line digital control algorithm for control system with bounded inputs. Bounded input is usually encountered by saturation of the actuator ability. The method is based on the already proposed "Error System Method" which has been applied for the design of the usual servo control system without bounded inputs. After transforming the original state equation of controlled object into the extended system which is called error system and defining a modified quadratic performance index so that on-line control will be possible, Maximum Principle is applied at each sampling period. Actuator is controlled by on-off command to obtain the maximum capacity of the actuator.

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We propose a cepstrum-based method for pitch estimation of speech signals in noisy environments. The cepstrum method is useful for pitch estimation. The performance of the method, however, degrades in noisy environments. Instead of the speech signal, we employ its windowless autocorrelation function for obtaining the cepstrum. The windowless autocorrelation function is a noise-reduced version of the speech signal where the periodicity is more apparent. Experimental results on male and female voices in the presence of white and color noise show that the gross pitch error becomes lower when using the proposed method compared with other related methods.

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Electromagnetic emissions leak confidential data of cryptographic devices. By exploiting such emissions, electromagnetic analysis (EMA) is performed with EM probes to extract secret information from these devices. Owing to the locality of EM emissions, namely, secret information may leak from multiple locations around cryptographic devices, it is difficult to determine the exact location before conducting an EMA. In this paper, signal variance of EM emissions during encryption is proposed to identify the information leakage of unprotected and protected cryptographic modules. We prove that signal variance is an equivalent metric to Difference of Means (DoM). Thus, by computing the higher signal variances based on near-field scan, the data-dependent EM emissions are disclosed, namely, the leakage locations are found. In addition, a small and low-cost probe is made to verify the proposed EMA on application-specific integrated circuit (ASIC) implementations. The experiment on AES PPRM1 implementation indicates that misjudgments of leakage are reduced, and the accuracy is improved 48.6% compared with existing methods. Moreover, the experiment of EMA against AES WDDL implementation shows that signal variance is also effective in exposing the leakage locations in the presence of countermeasures. The performance of EMA is enhanced.

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For multiple-input/multiple-output (MIMO) wireless communications systems employing spatial multiplexing transmission, we evaluate by simulation the parameter (i.e., population size, generation number) value requirements for detection based on genetic algorithm (GA) at the receiver. We assume transmit-correlated Rayleigh or Rician fading with realistic Laplacian power azimuth spectrum as well as azimuth spread (AS) and Rician K-factor selected according to the measurement-based WINNER II channel model, for several relevant scenarios. We first confirm that a GA whose parameters are suitably set converges to maximum-likelihood (ML)-like performance. Then, we study the effects of the number of antennas, modulation constellation size, scenario (i.e., AS and K values), and rank of the deterministic component of the channel matrix on parameter values required for GA in order to converge to ML-like performance. We find that, for poorer channel fading conditions, i.e., poorer achievable MIMO detection performance, the GA converges faster and for smaller population size. Therefore, selecting the GA parameter values according to the channel features may help achieve ML-like performance for lower complexity.

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