[Hospitals of the future confronting a changing epidemiology and the advance of medical research]

A review is offered of the most consistent sociological and epidemiological modifications taking place in this country, and their impact on the behaviour of diseases in the community. Following this picture on-the-move, analysis is performed on how designing, building and managing of the new hospitals are to be modified accordingly. In any case, new hospitals, specifically devoted to acute cases, will enter an assistance network including also territorial institutions, specifically devoted to the management of chronic pathologies.

[Flexibility and safety in hospitals]

The paper explains the reasons according to which the newly-planned hospitals must adopt the concept of advanced flexibility (structural, technological, organizational, diagnostic and therapeutic), in order to avoid the risk of being already obsolete at the moment of their opening, and this due to the fact that too much time elapses in this Country between the moment of planning a new hospital and the moment of the start of its activity. Flexibility is needed at different levels: at low or medium levels for what concerns administrative spaces and also patient rooms (except, in this latter case, when differential intensity of care is adopted); at advanced levelfor what concerns diagnostic and therapeutic areas, which must be rapidly adaptable to new solutions offered by advances in technology and organization. From a different standpoint, flexibility applies also to the fact that hospital must increasingly become a node of a large net including territorial health services: the latter devoted to take care of chronicity, while hospitals should concentrate on acute pathology. Of course the territory surrounding the hospital, through its outpatient service and consultories, is in charge also for first level diagnosy and therapy, leaving the hospital to more sophisticated activities.

Risk management of HBsAg or anti-HCV positive healthcare workers in hospital

Recommendations are made for controlling the transmission of the hepatitis B and hepatitis C viruses from healthcare workers to patients. These recommendations were based both on the literature and on experts' opinions, obtained during a Consensus Conference. The quality of the published information and of the experts' opinions was classified into 6 levels, based on the source of the information. The recommendations can be summarised as follows: all healthcare workers must undergo hepatitis B virus vaccination and adopt the standard measures for infection control in hospitals; healthcare workers who directly perform invasive procedures must undergo serological testing and the evaluation of markers of viral infection. Those found to be positive for: 1) HBsAg and HBeAg, 2) HBsAg and hepatitis B virus DNA, or 3) anti-hepatitis C virus and hepatitis C virus RNA must abstain from directly performing invasive procedures; no other limitations in their activities are necessary. Infected healthcare workers are urged to inform their patients of their infectious status, although this is left to the discretion of the healthcare worker; whose privacy is guaranteed by law. If exposure to hepatitis B virus occurs, the healthcare worker must undergo prophylaxis with specific immunoglobulins, in addition to vaccination.

Improved wavelet-based watermarking through pixel-wise masking

A watermarking algorithm operating in the wavelet domain is presented. Performance improvement with respect to existing algorithms is obtained by means of a new approach to mask the watermark according to the characteristics of the human visual system (HVS). In contrast to conventional methods operating in the wavelet domain, masking is accomplished pixel by pixel by taking into account the texture and the luminance content of all the image subbands. The watermark consists of a pseudorandom sequence which is adaptively added to the largest detail bands. As usual, the watermark is detected by computing the correlation between the watermarked coefficients and the watermarking code, and the detection threshold is chosen in such a way that the knowledge of the watermark energy used in the embedding phase is not needed, thus permitting one to adapt it to the image at hand. Experimental results and comparisons with other techniques operating in the wavelet domain prove the effectiveness of the new algorithm.

A new decoder for the optimum recovery of nonadditive watermarks

Watermark detection, i.e., the detection of an invisible signal hidden within an image for copyright protection or data authentication, has classically been tackled by means of correlation-based techniques. Nevertheless, when watermark embedding does not obey an additive rule, or when the features the watermark is superimposed on do not follow a Gaussian pdf, correlation-based decoding is not the optimum choice. A new decoding algorithm is presented here which is optimum for nonadditive watermarks embedded in the magnitude of a set of full-frame DFT coefficients of the host image. By relying on statistical decision theory, the structure of the optimum is derived according to the Neyman-Pearson criterion, thus permitting to minimize the missed detection probability subject to a given false detection rate. The validity of the optimum decoder has been tested thoroughly to assess the improvement it permits to achieve from a robustness perspective. The results we obtained confirm the superiority of the novel algorithm with respect to classical correlation-based decoding.

Capacity of full frame DCT image watermarks

The evaluation of the number of bits that can be hidden within an image through digital watermarking is a crucial topic, which has been addressed only for additive watermarks. The evaluation of watermark capacity is very important because it allows to put a theoretical upper bound on the amount of information that can be hidden into an image by a given watermarking procedure, regardless of the watermark extraction technique. It is the purpose of this work to suggest a methodology for the evaluation of the watermark capacity in a nonadditive, non-Gaussian framework, and to discuss the results we obtained by applying it to a set of standard images.

A quasi-Euclidean norm to speed up vector median filtering

For reducing impulsive noise without degrading image contours, median filtering is a powerful tool. In multiband images, as for example color images or vector fields obtained by optic flow computation, a vector median filter can be used. Vector median filters are defined on the basis of a suitable distance, the best performing distance being the Euclidean. Euclidean distance is evaluated by using the Euclidean norm which is quite demanding from the point of view of computation given that a square root is required. In this paper an optimal piece-wise linear approximation of the Euclidean norm is presented which is applied to vector median filtering.

Regularization of optic flow estimates by means of weighted vector median filtering

Vector median filtering has been recently proposed as an effective method to refine estimated velocity fields. Here, the use of a weighted vector median filtering is suggested to improve the regularization of the optic flow field across motion boundaries. Information about the confidence of the estimated pixel velocities is exploited for the choice of the filter weights. Experimental results, on both synthetic and real-world sequences, show the effectiveness of the proposed procedure.

A fast algorithm for 1-norm vector median filtering

A major drawback with vector median filters is their high computational complexity. A fast algorithm is presented for the computation of the vector median operator based on 1-norm. The algorithm complexity is investigated both from a theoretical and an experimental point of view. Simulation results are shown proving the complexity reduction achieved by the novel algorithm.