Algoritmo SOM com estrutura hierárquica e dinâmica aplicado a compressão de imagens

ln this work the implementation of the SOM (Self Organizing Maps) algorithm or Kohonen neural network is presented in the form of hierarchical structures, applied to the compression of images. The main objective of this approach is to develop an Hierarchical SOM algorithm with static structure and another one with dynamic structure to generate codebooks (books of codes) in the process of the image Vector Quantization (VQ), reducing the time of processing and obtaining a good rate of compression of images with a minimum degradation of the quality in relation to the original image. Both self-organizing neural networks developed here, were denominated HSOM, for static case, and DHSOM, for the dynamic case. ln the first form, the hierarchical structure is previously defined and in the later this structure grows in an automatic way in agreement with heuristic rules that explore the data of the training group without use of external parameters. For the network, the heuristic mIes determine the dynamics of growth, the pruning of ramifications criteria, the flexibility and the size of children maps. The LBO (Linde-Buzo-Oray) algorithm or K-means, one ofthe more used algorithms to develop codebook for Vector Quantization, was used together with the algorithm of Kohonen in its basic form, that is, not hierarchical, as a reference to compare the performance of the algorithms here proposed. A performance analysis between the two hierarchical structures is also accomplished in this work. The efficiency of the proposed processing is verified by the reduction in the complexity computational compared to the traditional algorithms, as well as, through the quantitative analysis of the images reconstructed in function of the parameters: (PSNR) peak signal-to-noise ratio and (MSE) medium squared error

Bioética e odontologia: um perfil dos problemas éticos vividos por cirurgiões-dentistas

Bioethics studies human behavior in the fields ofbiological sciences and health care. Tt strives for humanization in health services along with promoting the rights of patients. In view of the lack of dental research dealing with this topic, the present study was undertaken to identify, from the viewpoint of dental surgeons, ethical problems experienced in dental practice,understand how they occur and how professionals deal with them. It is a descriptive exploratory investigation within a qualitative approach. Empirical material was collected through semi-structured interviews performed with 15 dental surgeons who work both in private and public practice in the state of Rio Grande do Norte, Brazil. The content of the interviews was systemized and organized, resulting in the identification of topics, from which were grouped the ethical problems reported by the participants. The resu1ts indicate that many of the ethical problems coincide with infringements of the norms and mIes of the Dental Code of Ethics, confirming a dental ethic acquired during professional formation and therefore, inadequate for solving the problems that emerge in professional practice. Other questions stand out such as low salaries, competition and poor working conditions. Associated to these problems are lack of commitment and professional responsibility with the patients. Concem with maintaining user autonomy, guaranteeing access to specialized services, and the need for performing only procedures for which they are technically qualified arise in the responses, leading to difficulties in consolidating the principIes proclaimed by bioethics: autonomy, justice, nonmaleficence and beneficence. We concluded that the ethical problems identified in professional practice need to be understood beyond the dental dimension, towards a human approach. It is therefore necessary to incorporate health care management technologies into health practices, including dentistry, which implies recognizing the difTerent dimensions that surround individuaIs, that is, social, economic, political and cultural