Jerónimo Manuel Mora Pascual

Adjustable compression method for still JPEG images

There are a large number of image processing applications that work with different performance requirements and available resources. Recent advances in image compression focus on reducing image size and processing time, but offer no real-time solutions for providing time/quality flexibility of the resulting image, such as using them to transmit the image contents of web pages. In this paper we propose a method for encoding still images based on the JPEG standard that allows the compression/decompression time cost and image quality to be adjusted to the needs of each application and to the bandwidth conditions of the network. The real-time control is based on a collection of adjustable parameters relating both to aspects of implementation and to the hardware with which the algorithm is processed. The proposed encoding system is evaluated in terms of compression ratio, processing delay and quality of the compressed image when compared with the standard method. Our method performs real-time encoding/decoding still images based on JPEG standard.We introduce parameters that concern to the performance of the image processing.Adjusting the parameters affords to time/quality meet the application constraints.Experiments and quality test were made to probe the method consistency.

Time-precision flexible adder

A new conception of flexible calculation that allows us to adjust a sum depending on the available time computation is presented. More specifically, the objective is to obtain a calculation model that makes the processing time/precision more flexible. The addition method is based on carry-select scheme adder and the proposed design uses precalculated data stored in look-up tables, which provide, above all, quality results and systematization in the implementation of low level primitives that set parameters for the processing time. We report an evaluation of the architecture in area, delay and computation error, as well as a suitable implementation in FPGA to validate the design.

Resilience modeling by means of a set of recursive functions

This paper presents a computational framework to approach the resilience properties of the systems in many different domains. The proposal models elementary behaviors of the systems by means of a set of recursive functions defined by a few parameters. The parameter values determine wide intervals that characterize the behavioral patterns. The proposal provides a theoretical model of resilience related to the capability of a system to maintain its own pattern by displaying only minor changes when the parameter values of the model vary inside the intervals. This model lays out two powerful design principles for resilience issues, which are the parameterized form of the function and its recursive calculation. The model has been successfully applied to the study of well known system archetypes.

Exact numerical processing

A model of an exact arithmetic processing is presented. We describe a representation format that gives us a greater expressive capability and covers a wider numerical set. The rational numbers are represented by means of fractional notation and explicit codification of its periodic part. We also give a brief description of exact arithmetic operations on the proposed format. This model constitutes a good alternative for the symbolic arithmetic, in special when numerical exact values are required. As an example, we show an application of the exact numerical processing to calculate the perpendicular vector to another one for aerospace purposes.