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Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2012

Security and privacy practices of end-users on social media are an important area of research, as well as a top-of-mind concern for individuals as well as organizations. In recent years, we have seen a sharp increase in data breaches and cyber security threats that have targeted social media users. Hence, it is imperative that we try to better understand factors that affect an end-user’s adoption of effective security safeguards and privacy protection practices. In this research, we propose and validate a theoretical model that posits several determinants of end-user security and privacy practices on social media. We hypothesize relationships among various cognitive, affective and behavioral factors identified under the themes of posture, proficiency, and practices. These constructs and hypotheses are validated through empirical research comprising an online survey questionnaire, and structural equation modeling (SEM) analysis. The key findings of this study highlight the importance of cyber threat awareness and social media security and privacy self-efficacy, which have a direct impact on end-user security and privacy practices. Additionally, our research shows that use of general technology applications for security and privacy impacts the adoption of security and privacy practices on social media. In totality, our research findings indicate that proficiency is a better predictor or security and privacy practices as compared to the posture of an end-user. Factors such as privacy disposition, privacy concerns, and perceived risk of privacy violations do not have as significant or direct effect on security and privacy practices. Based on our research findings, we provide some key take-aways in the form of theoretical contributions, suggestions for future research, as well as recommendations for organizational security awareness training programs.

Product Development Processes have achieved a state of some maturity in recent years, but have focused primarily on structuring technical activities from the initiation of development to launch. We advocate major advances on three fronts; first, implementing an end-to-end process from the front end through field operations, second, integrating business considerations much better into the end-to-end process, and third, incorporating a performance improvement closed loop into the process. We call the resulting process a Product Development Business Process. Three initial applications are summarized. / Improving product development processes along three key vectors leads to greatly improved business performance. / Center for Innovation in Product Development

The Workshop for the Design and Control of Dexterous Hands was held at the MIT Artificial Intelligence Laboratory on November 5-6, 1981. Outside experts were brought together to discuss four topics: kinematics of hands, actuation and materials, touch sensing and control. This report summarizes the discussions of the participants and attempts to identify a consensus on applications, mechanical design, and control.

The demand for reduced-size components and devices is pervasive throughout industrial and commerical sectors. This drive to reduce the achievable size of parts and features has furthered the developmen of processes and tools capable of micro scale fabrication. In particular, one of the directions this field has taken is in scaling down traditional machine tools. Being a relatively young area of manufacturing, the area of miniaturized machining is still developing and a significant portion of work remains yet to be done. As a thorough understanding of this area is still developing, experimental tests play a significant role furthering this process. Therefore the direction of this project has been to explore this field using a predominantly experimental approach. The aim of it being to realize a miniaturized machine tool capable of fabricating features and even parts on the micro scale. Additionally the machine should be controlled as a standard milling machine and also be capable of generating free form three dimensional parts. In parallel to developing a machine tool, the project has also been directed at examining the machine's capabilities through a range of tests. For creating such a machine tool, the process was carried out in a two stages. Each stage involved a miniaturized machine tool at a different level. The first machine tool produced primarily served as a proof of concept structure. By performing a range of tests on this machine, it allowed for useful insights be to gained for developing the subsequent stage along with establishing some base performance characteristics which were also used for subsequent comparisons. The primary contributions made in this research include: the development of a miniaturized machine, the completion of experiments that map out the machine's capabilities, and theoretical calculations which further define these limits.

The increasing demands for improving magnetic resonance imaging (MRI) quality, especially reducing the imaging time have been driving the channel number of parallel magnetic resonance imaging (Parallel MRI) to increase. When the channel number increases to 64 or even 128, the traditional method of stacking the same number of radio-frequency (RF) receivers with very low level of integration becomes expensive and cumbersome. However, the cost, size, power consumption of the Parallel MRI receivers can be dramatically reduced by designing a whole receiver front-end even multiple receiver front-ends on a single chip using CMOS technology, and multiplexing the output signal of each receiver front-end into one channel so that as much hardware resource can be shared by as many channels as possible, especially the digitizer. The main object of this research is focused on the analysis and design of fully integrated multi-channel RF receiver and multiplexing technology. First, different architectures of RF receiver and different multiplexing method are analyzed. After comparing the advantages and the disadvantages of these architectures, an architecture of receiver front-end which is most suitable for fully on-chip multi-channel design is proposed and a multiplexing method is selected. According to this proposed architecture, a four-channel receiver front-end was designed and fabricated using TSMC 0.18μm technology on a single chip and methods of testing in the MRI system using parallel planar coil array and phase coil array respectively as target coils were presented. Each channel of the receiver front-end includes an ultra low noise amplifier (LNA), a quadrature image rejection down-converter, a buffer, and a low-pass filter (LPF) which also acts as a variable gain amplifier (VGA). The quadrature image rejection downconverter consists of a quadrature generator, a passive mixer with a transimpedance amplifier which converts the output current signal of the passive mixer into voltage signal while acts as a LPF, and a polyphase filter after the TIA. The receiver has an over NF of 0.935dB, variable gain from about 80dB to 90dB, power consumption of 30.8mW, and chip area of 6mm2. Next, a prototype of 4-channel RF receiver with Time Domain Multiplexing (TDM) on a single printed circuit board (PCB) was designed and bench-tested. Then Parallel MRI experiment was carried out and images were acquired using this prototype. The testing results verify the proposed concepts.

Squeeze film dampers (SFDs) provide viscous damping to attenuate excessive vibrations and enhance system stability in turbomachinery. SFDs are of special importance in aircraft engines which use rolling element support bearings that, by themselves, do not provide enough damping to ensure safe operation. A modular test rig capable of simulating actual operating conditions in aircraft jet engines is used to test two centrally grooved, end sealed, SFDs. Both SFDs have diameter D and nominal radial clearance c and consist of two parallel squeeze film lands separated by a deep circumferential groove of length LG and depth dG. A short length damper with film land lengths L and a long damper with land lengths 2L are tested. Piston rings seal the damper lands. An ISO VG2 lubricant is supplied to the SFD via three radial holes that discharge lubricant into the central groove. The lubricant passes through the damper lands and across the piston ring seals to finally exit the damper at ambient pressure. Circular orbit tests of amplitude ~0.5c and for static eccentricities varying from 0 to ~0.36c are conducted on the two sealed dampers. The instrumental variable filter method (IVFM) serves to identify the SFD dynamic force coefficients. The parameter identification range is 50Hz to 210Hz for the short damper and 110Hz to 250Hz for the long damper. Large amplitude dynamic pressures measured in the central groove demonstrate that the central groove does not divide the damper in two separate film lands, but the lubricant in the groove interacts with the squeeze film lands, hence contributing significantly to the SFD forced response. Dynamic pressures in the film lands and in the central groove reveal that both dampers operate free of air ingestion or cavitation for the tested static eccentricities and amplitudes of motion. Comparisons to test results for the same SFD configurations but with open ends demonstrate the effectiveness of the end seals on increasing the direct damping coefficients. For the sealed ends short length damper, the added mass coefficients are ~2 times larger and the damping coefficients are ~3.8 times larger than the respective coefficients of the open ends long damper. For the sealed ends long damper, the damping coefficients are ~2.8 times, and the added mass coefficients are ~3.1 times larger than coefficients from the open ends configuration. The identified SFD direct stiffness coefficients are nearly zero except at the maximum static eccentricity for the long damper. Predictions from a novel computational model that include the effects of the central groove, the lubricant feed holes and the end seals are in excellent agreement with results from the short length damper. For the long damper, the predicted damping coefficients are in good agreement with the test results, while the added mass coefficients are under predicted by ~25 percent. Experimental results from the two sealed SFD configurations lead to a better understanding of the effects of end seals as well as central feed groves on the SFD forced performance. The results presented in this thesis will help improve the effectiveness of SFDs aircraft jet engines.

The purposes of this study were to evaluate the frequency of documented prognosis discussions among terminally ill cancer patients, to identify correlates of having documented prognosis discussions, and to describe the content of prognosis discussions as documented in patient medical records. Sample data were collected from the randomly selected medical records of inpatients (n=210) aged 65 years or older and admitted with diagnoses of brain, pancreas, liver, gall bladder, or inoperable lung cancer from six large Connecticut hospitals. A standardized instrument was used to extract data concerning patient demographics, hospital course, prognosis discussions, and evidence of advance care planning. Prognosis discussions were recorded in 79 (38%) of medical records and were correlated with emergency admission status (p=0.004) and longer length of hospital stay (p=0.003) on multivariate analysis. Of the documented prognosis discussions, 63% were within one week of admission but after the first day, and 57% included the patient, 76% included the family, 77 % included the doctor, and 69% did not include another health staff member (n=79). Life sustaining treatment discussions and DNR orders were both associated with prognosis discussions (p=0.001 and p=0.001, respectively) and were more often documented after the prognosis discussions. Prognosis discussions included planning for care and treatment in 33 (42%) of discussions documented. In conclusion, we found that prognosis discussions were infrequently documented during the hospitalization of terminally ill patients diagnosed with cancer. We also found that advance care planning, such as discussions of life sustaining treatment and DNR orders, was significantly associated with prognosis discussions and more often occurred after prognosis was discussed.

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