Abstract
Knowledge discovery techniques try to extract patterns and concepts from raw data, and clustering certainly is one of the most popular processes in this research field. However, nowadays data is being produced in streaming fashion and distributed locations, turning most classical methods obsolete. This thesis addresses two different clustering problems in ubiquitous and streaming scenarios, presenting evidence of the advantages produced by applying distributed and streaming machine learning algorithms, and proposing new ones to solve the addressed problems.

Abstract
Implantable electronic cardiovascular devices (IECD) include a broad spectrum of devices that have the ability to maintain rhythm, provide cardiac resynchronization therapy, and/or prevent sudden cardiac death. The incidence of bradyarrhythmias and other cardiac problems led to a broader use of IECD, which turned traditional follow-up into an extremely heavy burden for healthcare systems to support. Our aim was to assess the impact of remote monitoring on the follow-up of patients with IECD. We performed a review through PubMed using a specific query. The paper selection process included a three-step approach in which title, abstract, and cross-references were analyzed. Studies were then selected using previously defined inclusion criteria and analyzed according to the country of origin of the study, year, and journal of publication; type of study; and main issues covered. Twenty articles were included in this review. Eighty percent of the selected papers addressed clinical issues, from which 94% referred clinical events identification, clinical stability, time savings, or physician satisfaction as advantages, whereas 38% referred disadvantages that included both legal and technical issues. Forty-five percent of the papers referred patient issues, from which 89% presented advantages, focusing on patient acceptance/satisfaction, and patient time-savings. The main downsides were technical issues but patient privacy was also addressed. All the papers dealing with economic issues (20%) referred both advantages and disadvantages equally. Remote monitoring is presently a safe technology, widely accepted by patients and physicians, for its convenience, reassurance, and diagnostic potential. This review summarizes the principles of remote IECD monitoring presenting the current state-of-the-art. Patient safety and device interaction, applicability of current technology, and limitations of remote IECD monitoring are also addressed. The use of remote monitor should consider the selection of patients, the type of disease, and centers' availability to receive, interpret and respond to device alerts. Before remote IECD monitoring can be routinely used, technical, procedure, and ethical/legal issues should be addressed.

Abstract
Although IT governance practices (like ITIL, which recommends on the use of Audit Trails (AT) for proper service level management) are being introduced in many Hospitals to cope with increasing levels of information quality and safety requirements, the standard maturity levels of hospital IT departments is still not enough to reach the level of frequent use of AT. This paper aims to address the issues related to the existence and quality of AT in Hospital Information Systems (HIS). A total of 5 hospitals participated in the study (4 CIO interviews and 7 AT from 4 hospitals). Very few AT are known to exist in these hospitals (about 1 per hospital in an estimate of 21 existing IS). The existing AT has poor quality (garbled, incomplete and misformatted information). CIOs should be much more concerned with the existence, quality and maintenance of AT. Recommendations include server clock synchronization, using advanced AT visualization tools, using also real-time auditing tools, and periodically audit the access to all data of a random patient.

Abstract
Although IT governance practices (like ITIL, which recommends on the use of audit logs for proper service level management) are being introduced in many Hospitals to cope with increasing levels of information quality and safety requirements, the standard maturity levels of hospital IT departments is still not enough to reach the level of frequent use of audit logs. This paper aims to address the issues related to the existence of AT in patient records, describe the Hospitals scenario and to produce recommendations. Representatives from four hospitals were interviewed regarding the use of AT in their Hospital IS. Very few AT are known to exist in these hospitals (average of 1 per hospital in an estimate of 21 existing IS). CIOs should to be much more concerned with the existence and maintenance of AT. Recommendations include server clock synchronization and using advanced log visualization tools.

Abstract
The use of computer systems to aid clinical decision making is growing. Besides clinical practice, computer applications, decision support systems or technologies can be used during dentistry and periodontology learning. A research was made using 30 searching expressions, based on MeSH Terms. A total of 17 articles were selected from the initial 249. Dental Students' Ability to Assess Gingival Health Status Software (DAAGS) and Virtual Learning Environment (VLE) are two examples of computer programs used in Priodontology learning. 3D technologies, electronic devices and image analysis systems are tools used during periodontal diagnosis. Dental informatics and periodontology are extremely connected, because, many systems, technologies or electronic devices could be used during diagnose, treatment or pre-operative phase. Computer applications could also be used to improve learning skills during pre-clinical and clinical stages, and at same time other technologies as 3D can present more detailed data to clinician, leading to a correct decision.

Abstract
Currently, in radiotherapy (RT) departments, there are different manufacturers and stand-alone information systems (IS) for single-purpose applications. These systems have most of the data distributed through different IS. The DICOM-RT extension has six objects that provide a standardized way of transferring the information circulating in the external beam RT. The aim of this study is to assess expert's opinion about DICOM-RT and IS interoperability in the RT context, through the characterization of Portuguese RT facilities, in terms of equipment and IS with the identification of existing interoperability problems. This study is cross-sectional, and the preliminary results presented in this paper are relative to the period May-July 2011. All Portuguese RT departments (i.e. 20) were invited to cooperate in the survey; the response rate was 40% (n=8), while 10% (n=2) of the institutions did not authorize the RT departments to participate. The preliminary results show that the RT departments have some equipment and IS from different vendors contributing for heterogeneity of RT workflows. The experts somehow attribute importance to interoperability, but have low knowledge about their own IS integrations, and DICOM-RT. Compliance with DICOM-RT is recommended when acquiring new RT IS to optimise the interoperability.