Marcos R. A. Morais

A Fast and Memory Efficient Huffman Decoding Method for the MPEG-4 AAC Standard

Huffman coding is an efficient coding technique that is largely used in applications that need a lossless data compression. We present in this paper a novel method for Huffman decoding that increases the performance and keeps the memory consumption low. The main idea is to add information about the number of bits necessary to search for the next possible symbol in the Huffman tree. The proposed method has been used in the implementation of an MPEG-4 AAC decoder, and has proven to be extremely fast to decode short symbols that are the ones with higher probability to occur in a bitstream.

Behavior coordination in multi-robot systems

A distributed swarm navigation technique is presented for terrestrial mobile robots. Each robot has its own behavior-based controller that coordinates its basic behaviors by using a hybrid automata. The coordination allows flocking behavior as a result of parallel composition of individual robot automata. The distributed navigation problem is formulated for differential-drive wheeled robots equipped with odometry, compass, and laser range sensor. An interference analysis is made to evaluate the system performance under different configuration of initial parameters. The individual controller allows to expand the number of behaviors. This permits cohesion, align and safe navigation in the robot swarm. The pseudo-experimental results obtained in a ROS-GAZEBO environment were quite positive demonstrating the correctness and feasibility of the proposed solution.

Implementation of a FPGA-based data acquisition and processing system for image sensors employed in SPR biosensing

Optical biosensors based on surface plasmon resonance (SPR) are powerful tools for detecting biomolecules. In this paper, a reconfigurable image acquisition and processing system for SPR sensors is presented. The system uses a FPGA device for acquiring and processing data from an image sensor to determine the angle at which the minimum reflectivity of the optical multilayer arrangement occurs. A frequency domain processing for smoothing the SPR signal is implemented in hardware. The system also incorporates a communication interface for sending processed and unprocessed data from the FPGA to a remote device and receiving settings regarding the data acquisition and data processing strategies.

Improved data extraction algorithm for biosensors utilizing surface plasmon resonance sensing

Biosensors based on surface plasmon resonance enable us to detect biochemical compounds by tracking the changes in the reflectivity of a multi-layered system excited with p-polarized light. In this paper, a method to detect the changes on resonance condition is proposed. The method is based on a single sinusoidal approximating function, presents low computational complexity, improved noise immunity, and provides a quite accurate measurement in a single signal processing step. Simulation and experimental results are presented to demonstrate the feasibility of the proposed solution as well as to show its superior noise immunity features when compared to well known resonance detection methods.

Visual feedback trajectory planning for object handling and obstacle avoidance

In this article a visual feedback control system implementation is presented. The proposed system integrates a trajectory planning method into the controller of a five-degree-of-freedom manipulator aiming to simplify object handling and obstacle avoidance. The system aims the intelligent handling of several parts, generating obstacle free paths whenever possible. The workspace information is provided by a redundant vision system: a RGB camera placed over the handler actuator and a fixed RGB-D camera.

Determining lead-acid battery DC resistance by tremblay battery model

Internal resistance measurement of a lead-acid battery is discussed. A criterion based on the battery model discharge equation is used to determine the value of internal resistance. The mathematical model chosen to represent the electrochemical battery and the methods of calculating the internal resistance of a battery is shown. A simulation study is used to demonstrate the feasibility of this measure resistance.

Lifetime estimation technique for lead-acid batteries

Battery mathematical models can be employed to predict its behavior under various charging and discharging conditions, and in some applications, they are key elements for the successes of the design. In this paper, it is analyzed a lead-acid battery model for voltage and lifetime estimation. The chosen model synthesis is based on an electrical equivalent circuit, and has the features that allow it to be used in the calculation of the remaining capacity. The lifetime model employs an adaptive update mechanism during the simulation such that the battery performance is reduced depending on the operating conditions. This paper objective is to generalize the analyzed mathematical system to be used in any lead-acid battery. Both the model and the estimation algorithm are evaluated with two batteries with same voltage and nominal capacity. The generalization of equation is made by the addition of three new parameters to minimize an objective function based on the least squares error. The study is based on a specific scenario that makes the battery reached the end of its lifetime. With the addition of new parameters, the RMS error between real capacity and calculated capacity are evaluated.

SPR sensor for tampering detection in biofuels

This work presents a sensor based on surface plasmon resonance phenomenon and combined with dc-sheet resistance monitoring for detecting tampering of ethanol fuel. To demonstrated the feasibility of the proposed sensor, hydrated and anhydride ethanol fuel were tested. Tampering ethanol with methanol and with increasing water content have been used to evaluate the capabilities of the proposed sensing arrangement.

CleveRemote Adaptive environments using Bluetooth/infrared transceivers

This paper describes a new concept of a location-based remote control. This device analysis the user location and preferences to adapt the environment according to the customer needs. It makes the operation of the remote control easier and more pleasant.

VLSI Implementation of Contour Extraction from Real Time Image Sequences

In this work a parallel architecture is proposed for VLSI implementation of a dataflow algorithm for 2D boundary (or contour) detection.The algorithm works on the gradient image and uses a set of primitive paths to generate all possible contour paths on a neighborhood defined by a 5×5 window. The objective is to determine whether or not the neighborhood central pixel belongs to a continuous boundary line passing across the window. Test results show that one-pixel wide continuous boundary lines can be extracted using this algorithm.