Reclaiming Control over Personal Data with Blockchain Technology: An Exploratory Study

With the digitalization and increasing number of Internet users, more and more personal data breaches occur. Many people are not aware of their personal data rights and have not received any instructions on how to act in situations such as when their personal data is abused. This is something that illustrates the flaws of the Internet. A technology that provides solutions to some of these problems, such as trust and transparency, is the blockchain technology. Hence, the objective of this paper is to investigate knowledge about personal data rights and to explore the design of a prototype of a blockchain application for increased security and transparency. User tests were conducted, highlighting the greatest needs for users to feel secure and in control over their personal data. This knowledge provide the foundation for a prototype based on blockchain technology that gives the users increased security and forces those who store personal data to be more transparent with the usage

Single and multi-junction thin film silicon solar cells for flexible photovoltaics

This thesis investigates amorphous (a-Si:H) and microcrystalline (μc-Si:H) solar cells deposited by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) in the n-i-p or substrate configuration. It focuses on processes that allow the use of non transparent and flexible substrates such as plastic foil with Tg 1 micron) against thin (<0.3 micron) absorber layer, the antireflection effect of ITO becomes more effective and the structure with the flat TCO provides as much light trapping as the rough LP-CVD ZnO. Finally, the conformality of the layers is investigated and guidelines are given to understand the effectiveness of the light trapping in devices deposited on periodic gratings. In the second part, we quantitatively describe the effect of continually varying the substrate morphology for the device in the n-i-p configuration on open-circuit voltage (Voc) and fill factor (FF). Transmission electron microscope (TEM) observations show that V shape morphology creates nano- cracks and reduces the Voc and FF of the solar cells. Hence, we investigate cell designs and processes that avoid Voc and FF losses. For a-Si:H solar cells, we introduce an amorphous silicon carbide n-layer (n-SiC), a buffer layer at the n/i interface, and show that the new cell design yields high Voc and FF on both flat and textured substrates, contrary to the usual microcrystalline silicon n-doped layer. Finally, the beneficial effect of our optical and electrical findings is used to fabricate a-Si:H solar cell with an initial efficiency of 8.8 % and stabilized efficiency of 7% on plastic foil. We find that for our reduced temperature processes windows, the light-induced degradation of a-Si:H solar cells depends strongly on the thickness of the absorber layer. Indeed, the relative efficiency degradation is reduced from 27% to 17% for 400 nm and 200 thick cells, respectively. This degradation can be further lowered to 15 % in a-Si/a-Si tandem structure, and still using a total 300 nm thick absorber layer. For μc-Si:H solar cells, we introduce a buffer layer with a higher amorphous fraction between the n-doped and intrinsic layer. Our study reveals that the buffer layer limits the formation of voids and porous areas (nano-cracks), which promotes oxygen diffusion in the μc-Si:H material. Therefore, this layer mitigates the Voc and FF losses which enhances the performance of the μc- Si:H solar cell. By applying our findings, we make μc-Si:H solar cells with an efficiency of 8.7% on plastic foil for an only 1.2 m absorber layer thickness. The micromorph solar cell (stack of amorphous and microcrystalline cells) concept is the key for achieving high efficiency stabilized thin film silicon solar cells. We present results with and without an intermediate reflector. In particular, we introduce an original device structure that allows a better control of the layer growth and of the light in-coupling into the two sub-cell components. It is based on an asymmetric intermediate reflector (AIR), which increases the effective thickness of the a-Si:H by a factor of more than three. Hence, the a-Si:H thickness reduction diminishes the light-induced degradation, and micromorph tandem cells with 11.2 % initial and 9.8% stabilized efficiencies (1000h, 50°C, 100mW/cm2) are achieved on plastic foil. The stabilized Jsc of the n-i-p tandem solar cells is close to 12 mA/cm2, which offers the possibility for the low Tg flexible substrate technology to compete with state of the art stabilized thin film silicon devices. Based on the results obtained here, a further optimisation of the ITO/p and p-i interfaces, should allow it to be possible to exceed 12% stabilized efficiency on low Tg plastic substrate for micromorph tandems cells

The User Experience of Personalized Content

Content in digital services is often filtered for users based on individual preferences with the possible consequence of creating a state referred to as a “filter bubble”. The objective of this paper is to examine which of a user’s inherent needs that are important to satisfy when a user is consuming personalized content in a digital service. The paper uses a survey to measure the need for autonomy, competence and relatedness of the Self- Determination Theory when users are consuming filtered content in digital services. The results show that the investigated services fail to satisfy all needs. A satisfactory user experience should include the opportunity for the user to satisfy the need for autonomy, competence and relatedness. For autonomy, transparency of filtering and choice about filtering should be offered. For competence, it is essential to offer content that the user can learn from, and also provide the right amount of choice throughout the service. The danger of filter bubbles is not personalization, but to remove choice about personalization

User Experience Design and Digital Nudging in a Decision Making Process

When using online nudges to steer people in the right direction while they are making a decision, there is usually one preferable outcome. What might happen if the user experience is inadequate, will the nudges still work or might they be undermined? In this paper we investigate the correlation between user experience and digital nudges in a decision making process. A user A/B test was conducted to investigate the problem. The test participants visited one of two websites that included the same nudges where they were nudged to choose option (a) instead of (b). The only difference in the websites was the quality of the user experience, one website design had a good user experience while the other one offered an inadequate user experience. The results showed that everyone who was assigned the good user experience chose (a), while two of the inadequate experience participants chose (b). The results indicate that user experience design can be used for digital nudging

Predicting grain protein concentration in winter wheat (Triticum aestivum L.) based on unpiloted aerial vehicle multispectral optical remote sensing

Prediction models for crude protein concentration (CP) in winter wheat (Triticum aestivum L.) based on multispectral reflectance data from field trials in 2019 and 2020 in southern Sweden were developed and evaluated for independent trial sites. Reflectance data were collected using an unpiloted aerial vehicle (UAV)-borne camera with nine spectral bands having similar specification to nine bands of Sentinel-2 satellite data. Models were tested for application on near-real time Sentinel-2 imagery, on the prospect that CP prediction models can be made available in satellite-based decision support systems (DSS) for precision agriculture. Two different prediction methods were tested: linear regression and multivariate adaptive regression splines (MARS). Linear regression based on the best-performing vegetation index (the chlorophyll index) was found to be approximately as accurate as the best performing MARS model with multiple predictor variables in leave-one-trial-out cross-validation (R-2 = 0.71, R-2 = 0.70 and mean absolute error 0.64%, 0.60% CP respectively). Models applied on satellite data explained to a small degree between-field variations in CP (R-2 = 0.36), however did not reproduce within-field variation accurately. The results of the different methods presented here show the differences between methods used and their potential for application in a DSS

Прилад для вимірювання розмірів деталей із низькомодульних матеріалів

Background: Enhanced secondary preventive follow-up after stroke or transient ischemic attack (TIA) is necessary for improved adherence to recommendations regarding blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) levels. We investigated whether nurse-led, telephone-based follow-up was more efficient than usual care at improving BP and LDL-C levels at 12 months after hospital discharge. Methods: We randomized 537 patients to either nurse-led, telephone-based follow-up (intervention) or usual care (control). BP and LDL-C measurements were performed at 1 month (baseline) and 12 months post-discharge. Intervention group patients who did not meet target values at baseline received additional follow-up, including titration of medication and lifestyle counselling, to reach treatment goals (BP &lt; 140/90 mmHg, LDL-C &lt; 2.5 mmol/L). Results: At 12 months, mean systolic BP, diastolic BP and LDL-C was 3.3 (95% CI 0.3 to 6.3) mmHg, 2.3 mmHg (95% CI 0.5 to 4.2) and 0.3 mmol/L (95% CI 0.1 to 0.4) lower in the intervention group compared to controls. Among participants with values above the treatment goal at baseline, the difference in systolic BP and LDL-C was more pronounced (8.0 mmHg, 95% CI 4.0 to 12.1, and 0.6 mmol/L, 95% CI 0.4 to 0.9). A larger proportion of the intervention group reached the treatment goal for systolic BP (68.5 vs. 56.8%, p = 0.008) and LDL-C (69.7% vs. 50.4%, p &lt; 0.001). Conclusions: Nurse-led, telephone-based secondary preventive follow-up, including medication adjustment, was significantly more efficient than usual care at improving BP and LDL-C levels by 12 months post-discharge

Flexible micromorph tandem a-Si/µc-Si solar cells

The deposition of a stack of amorphous (a-Si:H) and microcrystalline (µc- Si:H) tandem thin film silicon solar cells (micromorph) requires at least twice the time used for a single junction a-Si:H cell. However, micromorph devices have a higher potential efficiency, thanks to the broader absorption spectrum of µc-Si:H material. High efficiencies can only be achieved by mitigating the nanocracks in the µc-Si:H cell and the light-induced degradation of the a- Si:H cell. As a result, µc-Si:H cell has to grow on a smooth substrate with large periodicity (>1 µm) and the a-Si:H cell on sharp pyramids with smaller feature size (~350 nm) to strongly scatter the light in the weak absorption spectra of a-Si:H material. The asymmetric intermediate reflector introduced in this work uncouples the growth and light scattering issues of the tandem micromorph solar cells. The stabilized efficiency of the tandem n-i-p/n-i-p micromorph is increased by a relative 15% compared to a cell without AIR and 32% in relative compared to an a-Si:H single junction solar cells. The overall process (T<200 °C) is kept compatible with low cost plastic substrates. The best stabilized efficiency of a cell deposited on polyethylene-naphthalate plastic substrate is 9.8% after 1000 h of light soaking at Voc, 1 sun, and 50 °

ASYMMETRIC INTERMEDIATE REFLECTOR FOR N-I-P MULTI-JUNNCTION THIN FILM SILICON SOLAR CELLS

We investigate n-i-p/n-i-p micromorph tandem cells deposited at process temperature below 200°C in order to be compatible with low Tg (<180°C) plastic substrates. In this configuration, the thick microcrystalline cell is grown first and tends to smoothen the initial substrate texture. Hence, the amorphous cell is grown on an almost flat surface that yields low current density. To prevent this effect and to obtain a proper current matching, an asymmetric intermediate reflector, creating a structure favourable for a-Si:H cell, is developed and incorporated into the cells. The effective optical thickness of the amorphous intrinsic layer can be increased by a factor of more than three. Hence, the light induced degradation is reduced below 10% for 180 nm amorphous layer whereas the degradation for cells without intermediate reflector is between 15-20%, because 300 nm amorphous top cell is required for matching. We present a-Si:H/a-Si:H micromorph tandem cells with 10.1 % stable efficiency after 1000h light soaking and triple junction a-Si:H/a-Si:H/μc-Si:H solar cell with initial efficiency of 10.4%

A New View of Microcrystalline Silicon: The Role of Plasma Processing in Achieving a Dense and Stable Absorber Material for Photovoltaic Applications

To further lower production costs and increase conversion efficiency of thin-film silicon solar modules, challenges are the deposition of high-quality microcrystalline silicon (μc-Si:H) at an increased rate and on textured substrates that guarantee efficient light trapping. A qualitative model that explains how plasma processes act on the properties of μc-Si:H and on the related solar cell performance is presented, evidencing the growth of two different material phases. The first phase, which gives signature for bulk defect density, can be obtained at high quality over a wide range of plasma process parameters and dominates cell performance on flat substrates. The second phase, which consists of nanoporous 2D regions, typically appears when the material is grown on substrates with inappropriate roughness, and alters or even dominates the electrical performance of the device. The formation of this second material phase is shown to be highly sensitive to deposition conditions and substrate geometry, especially at high deposition rates. This porous material phase is more prone to the incorporation of contaminants present in the plasma during film deposition and is reported to lead to solar cells with instabilities with respect to humidity exposure and post-deposition oxidation. It is demonstrated how defective zones influence can be mitigated by the choice of suitable plasma processes and silicon sub-oxide doped layers, for reaching high efficiency stable thin film silicon solar cells

Do semantic standards lack quality? : a survey among 34 semantic standards

The adoption of standards to improve interoperability in the automotive, aerospace, shipbuilding and other sectors could save billions. While interoperability standards have been created for a number of industries, problems persist, suggesting a lack of quality of the standards themselves. The issue of semantic standard quality is not often addressed. In this research we take a closer look at the quality of semantics standards, development processes, and survey the current state of the quality of semantic standards by means of a questionnaire that was sent to standards developers. This survey looked at 34 semantic standards, and it shows that the quality of semantic standards for inter-organizational interoperability can be improved. Improved standards may advance interoperability in networked business. Improvement of semantic standards requires transparency of their quality. Although many semantic standard development organisations already have quality assurance in place, this research shows that they could benefit from a quality measuring instrument