André S. R. Kuramoto

Sets of sequences for QS-CDMA systems with interference cancellation over multipath Rayleigh fading channels

Walsh-Hadamard, QS, Lin-Chang, LCZ-GMW, ZCZ sets of sequences are compared. The comparison is accomplished by analyzing the conventional receiver (RAKE) and a parallel interference canceller (PIC) receiver performance using each one of these sequence sets in a multipath Rayleigh fading channel and similar system loads in a quasi-synchronous condition.

Spreading sequences comparison for DS-CDMA systems

Walsh-Hadamard, QS (QS-sequence), Lin-Chang, ZCZ, PS and SP sets of spreading sequence characteristics are compared. The comparison is accomplished by analyzing the correlation properties, under the conventional receiver performance, using each one of these sets of sequences in an AWGN channel and similar system loads in quasi-synchronous condition.

Effectiveness of signal excitation design methods for ill-conditioned processes identification1

Abstract A comparison of the effectiveness between five different methods to generate excitation input signals for the identification of ill-conditioned processes is presented. Evaluation is made using a 2x2 MIMO model of a high purity distillation column. Results are analysed using a proposed factor, which evaluates dispersion of the system output plane.

Structures’ Influence on Model-Plant Mismatch Detection Methods in MPC Using Partial Correlation

One of the challenges that still needs to be overcome in order to improve the performance of the model predictive control (MPC) is its maintenance. Re-identification of the process is one of the best options available to update the internal model of the MPC, in order to increase the production and improve efficiency. However, re-identification is costly Researchers have proposed two different methods able to detect plant mismatch through partial correlation analysis. Using these techniques, instead of re-identifying all the sub-models in the process, only a few inputs with significant mismatch would have to be perturbed and only the degraded portion of the model would be updated. Nevertheless, there isn’t enough information and analysis about the influence of the choice of the structures for identification (as FIR, ARX, ARMAX and OE) on partial correlation results. This paper demonstrates that the Carlsson method is a particular solution of the Badwe et al. method, when the models used on the identification process are FIR structures. Moreover, some other types of structures will were analyzed in order to check if they are suitable for the partial correlation procedure to detect plant mismatches.

Sequence design for MPG QS-CDMA systems based on heuristic combinatorial optimization

This paper deals with a quasi-synchronous code division multiple access (QS-CDMA) system with a multiple processing gain (MPG) variable data rate scheme in the uplink direction and subject to multipath fading channels. An analytic expression is obtained for the signal-to-noise plus interference ratio (SNIR) at the Rake receiver output (finger). In order to maximize the SNIR, three combinatorial optimization methods applied to sequences selection are compared. Then, sequence selection methodology for this class of system is evaluated, comparing the local search optimization results with unitary Hamming distance (1-opt LS), evolutionary programming with cloning (EP-C), and simulated annealing (SA) ones. The contribution of this work consists of considering the self-interference (SI) effect, besides the multiple access interference (MAI), in the description of the proposed objective function for sequence selection and a compared analysis of three heuristic algorithms maximizing that SNIR. Also, numeric results have demonstrated the effectiveness of the proposed method for the QS-CDMA sequences selection. Copyright

Set of Sequences for QS-CDMA Systems with Multi-User Detection and Multipath-Fading Channels

In this work Walsh–Hadamard, QS, Lin–Chang, LCZ-GMW, ZCZ sets of sequences are compared. The comparison is accomplished by analyzing the conventional receiver (Rake) and a parallel interference canceller (PIC) receiver performance using each one of these sequence sets in a multipath Rayleigh fading channel and similar system loads in quasi-synchronous condition.

Optimization of H2 Production in a Hydrogen Generation Unit

Abstract This article presents the results of the use of advanced process control algorithm to optimize the H2 production of Henrique Lage Refinery (REVAP) located in the state of Sao Paulo, Brazil. The control methodology is applied to the second Hydrogen Generation Unit (HGU) of the Refinery and consists of optimizing its production in order to guarantee the hydrogen supply for the refinerys header without production loss. The designed controller had the support of dynamic simulation for disturbances modelling and identification which contributed for the improvement of the control strategy. The results in this paper represents the application of the control methodology in the real plant.