Search

Technology has an increasing role in the modern day health care system. Healthcare Technology Management (HTM) is an area of biomedical engineering including the domains of planning, needs assessment, selection, procurement, donations, inventory, installation and maintenance of medical equipment (WHO, 2017). This thesis deals with HTM in Dutch hospitals from the viewpoint of procurement of high-cost medical equipment. Procurement is considered the main shifting point between resources and being able to provide care with the available technology.Through literature search and semi-structured interviews, we study the decision process for health technology procurement from the hospitals perspective, to answer the following question: What procedures improve the effectiveness of the multi-layered decision making process of procurement of health technology in hospitals in the Netherlands? To be able to answer this question, three perspectives are described.First of all, actor and stakeholder interaction within the decision arena. In the hospital we can define three actor types: clinical, operational and business actors. The project team for procurement processes generally includes a project leader, medical technology and clinical physics, procurement and users. Although it is preferable to have business oriented project leaders, the role is often fulfilled by operational or even clinical actors.The second perspective concentrates on external influences on the decision arena. Two types of external influence are described: regulation and industry influence. The recently introduced agreement medical technology is considered to be the most influential piece of regulation, despite it being a directive and not a law. The agreement medical technology introduced new procedures in terms of risk analysis and justification and induced big steps towards an increasingly formalized procurement process. Despite the fact that the covenant and all other applicable regulation steers to set

Hierarchical Temporal Memory (HTM) is an unsupervised learning algorithm inspired by the features of the neocortex that can be used to continuously process stream data and detect anomalies, without requiring a large amount of data for training nor requiring labeled data. HTM is also able to continuously learn from samples, providing a model that is always up-to-date with respect to observations.These characteristics make HTM particularly suitable for supporting online failure prediction in cloud systems, which are systems with a dynamically changing behavior that must be monitored to anticipate problems. This paper presents the first systematic study that assesses HTM in the context of failure prediction.The results that we obtained considering 72 configurations of HTM applied to 12 different types of faults introduced in the Clearwater cloud system show that HTM can help to predict failures with sufficient effectiveness (F-measure = 0.76), representing an interesting practical alternative to (semi-)supervised algorithms.

The power conversion efficiency (PCE) of metal halide perovskite solar cells (PSCs) has increased from 3.8 to 25.2% in the last decade, making perovskite the most promising material for future solar cells. However, further PCE and stability improvement are important for successful commercialization. Therefore, the aim of this thesis is to investigate ways of increasing PCE and addressing instability of PSCs.Initial PCE increase has been observed during ambient storage for many PSCs. Through a series of experiments, the origin of the storage effect was attributed to a combination of i) defect reduction in perovskite, ii) conductivity increase, and iii) evolution of the highest occupied molecular orbital (HOMO) in spiro-OMeTAD. In particular, the HOMO level change was revealed to play a significant role in PCE improvement. In terms of strategy for improving PCE, a novel passivation technique was developed by forming 2D/3D perovskite thin layer using a mixture of formamidinium iodide and iso-butylammonium iodide on the perovskite layer. This technique achieved a maximum PCE of 21.7%, while simultaneously enhancing device light and moisture stability. The defect density reduction, the uniform surface coverage of the passivation material and the suppressed ion migration by bulky organic cation were found to be the key parameters for PCE and stability improvement.Storage effect was also studied for these passivated PSCs. It is found that the changed conduction band of passivated perovskite influenced the initial temporal change of PCE, suggesting the importance of interface band alignment by passivation and conductive materials. Also, despite significantly suppressed non-ideal recombination at the surface/interface by passivation, analysis of the dominant recombination revealed the need for defect reduction in bulk perovskite. Consequently, by engineering the composition of bulk perovskite layers to decrease defects, PCE of 22.2% was achieved. Finally, the effects of remo

The electronic properties of Triphenylamine (TPA) in gas phase and adsorbed on gold(111) have been simulated with Quantum Espresso using Density Functional Theory (DFT). To better understand how the presence of a gold surface affects sunlight absorption in the system, partial Density Of States (pDOS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) of the system have been calculated. To describe the electronic excitation, three different methods have been used, No Core Hole (NCH), Full Core Hole (FCH) and Half Core Hole (HCH) approximation. The excitation of the TPA molecule was made in the nitrogen (N) atom and in the four different carbon (C) atoms with different electronic environments, C-ipso, C-ortho, C-meta and C-para. When using the HCH method, the absorbing atom must be described by a pseudopotential (PP) which includes half of a hole in the 1s orbital. This PP has been generated and a detailed summary of the process is described. The TPA/gold system relaxes to a position with the central N atom of TPA above an gold (Au) atom in the second layer of the surface and at a distance of 3.66 Angstrom, to the first layer. TPA keeps its symmetry with only small differences in the length of atomic bonds when adsorbed. The most striking result of this study is how the band gap of TPA is affected by the gold layer. From the pDOS we can observe that TPA in gas phase has a clear band gap of 2.2 eV with C-ortho dominating in the valence region and the four carbons dominating in the first unoccupied states. When depositing the molecule on the surface of Au(111), the band gap is essentially gone and a number of states appear between the previous highest occupied and lowest unoccupied molecular orbital in TPA. These new states align in energy with three clusters of states of the gold suggesting an interaction between the molecule and the surface. In the generated NEXAFS of nitrogen and carbon in TPA gas phase, one can observe a small pre-peak before the first unoccupie

Perovskite solar cells are today one of the hottest topics in photovoltaic devices. Compared to traditional c-Si, thin-film CIGS or CdTe solar cells, the fabrication of this type of solar cell is much cheaper, because production does not require ownership of a very expensive equipment and instrumentation. However, it has to be taken into account it has some initial issues as well as other newly developed technologies in the early stages of preparation for a commercial production. This paper deals with a newly synthesized hole transport material as a replacement of commercially available high-cost Spiro-OMETAD transport material. This commercial material has two main issues. Firstly, its production is very expensive and secondly it does not perform a function of a passivation layer for a sensitive perovskite layer. Our newly developed molecule has a positive effect on achieving long-term stable perovskite along with much cheaper production. The produced perovskite solar cell does not achieve highest power conversion efficiency, but they still look promising inf the view of long-term consistent performance.

Perovskite solar cells are today one of the hottest topics in photovoltaic devices. Compared to traditional c-Si, thin-film CIGS or CdTe solar cells, the fabrication of this type of solar cell is much cheaper, because production does not require ownership of a very expensive equipment and instrumentation. However, it has to be taken into account it has some initial issues as well as other newly developed technologies in the early stages of preparation for a commercial production. This paper deals with a newly synthesized hole transport material as a replacement of commercially available high-cost Spiro-OMETAD transport material. This commercial material has two main issues. Firstly, its production is very expensive and secondly it does not perform a function of a passivation layer for a sensitive perovskite layer. Our newly developed molecule has a positive effect on achieving long-term stable perovskite along with much cheaper production. The produced perovskite solar cell does not achieve highest power conversion efficiency, but they still look promising inf the view of long-term consistent performance.

Perovskite solar cells are today one of the hottest topics in photovoltaic devices. Compared to traditional c-Si, thin-film CIGS or CdTe solar cells, the fabrication of this type of solar cell is much cheaper, because production does not require ownership of a very expensive equipment and instrumentation. However, it has to be taken into account it has some initial issues as well as other newly developed technologies in the early stages of preparation for a commercial production. This paper deals with a newly synthesized hole transport material as a replacement of commercially available high-cost Spiro-OMETAD transport material. This commercial material has two main issues. Firstly, its production is very expensive and secondly it does not perform a function of a passivation layer for a sensitive perovskite layer. Our newly developed molecule has a positive effect on achieving long-term stable perovskite along with much cheaper production. The produced perovskite solar cell does not achieve highest power conversion efficiency, but they still look promising inf the view of long-term consistent performance.

Perovskite solar cells are today one of the hottest topics in photovoltaic devices. Compared to traditional c-Si, thin-film CIGS or CdTe solar cells, the fabrication of this type of solar cell is much cheaper, because production does not require ownership of a very expensive equipment and instrumentation. However, it has to be taken into account it has some initial issues as well as other newly developed technologies in the early stages of preparation for a commercial production. This paper deals with a newly synthesized hole transport material as a replacement of commercially available high-cost Spiro-OMETAD transport material. This commercial material has two main issues. Firstly, its production is very expensive and secondly it does not perform a function of a passivation layer for a sensitive perovskite layer. Our newly developed molecule has a positive effect on achieving long-term stable perovskite along with much cheaper production. The produced perovskite solar cell does not achieve highest power conversion efficiency, but they still look promising inf the view of long-term consistent performance.

Perovskite solar cells (PSCs) have shown a significant improvement in power conversion efficiency (PCE) in the last few years. However, instability of PSCs is still a barrier for successful industrialization. In particular, spiro-OMeTAD with additives, despite a popular choice for hole transport material (HTM) in PSCs, is one of the causes for device thermal instability. In this work, one of additives in HTM, 4-tert-butylpyridine (tBP) is proved to be a factor of device instability under thermal treatment. Simple solution engineering which excludes the use of tBP in the HTM results in better device stability. The origin of thermal stability improvement shown in this work is attributed to the suppression of morphological change of HTM. Further researches towards thermal stability of perovskite material and dopant-free HTM should be essential since tBP removal was not able to solve the thermal stability issue.

This thesis generalizes techniques for processing IoT data streams, semantically enrich data with contextual information, as well as complex event processing in IoT applications. A case study for ECG anomaly detection and signal classification was conducted to validate the knowledge foundation.

The photovoltaic characteristics of CsBi3I10-based solar cells with three dopant-free hole-conducting polymers are investigated. The effect on charge generation and charge recombination in the solar cells using the different polymers is studied and the results indicate that the choice of polymer strongly affects the device properties. Interestingly, for the solar cell with poly[[2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl]-2,5-thiophenediyl] (TQ1), the photon-to-current conversion spectrum is highly improved in the red wavelength region, suggesting that the polymer also contributes to the photocurrent generation in this case. This report provides a new direction for further optimization of Bi-halide solar cells by using dopant-free hole-transporting polymers and shows that the energy levels and the interaction between the Bi-halide and the conducting polymers are very important for solar cell performance.

Financial institutions manage numerous portfolios whose risk must be managed continuously, and the large amounts of data that has to be processed renders this a considerable effort. As such, a system that autonomously detects anomalies in the risk measures of financial portfolios, would be of great value. To this end, the two econometric models ARMA-GARCH and EWMA, and the two machine learning based algorithms LSTM and HTM, were evaluated for the task of performing unsupervised anomaly detection on the streaming time series of portfolio risk measures. Three datasets of returns and Value-at-Risk series were synthesized and one dataset of real-world Value-at-Risk series had labels handcrafted for the experiments in this thesis. The results revealed that the LSTM has great potential in this domain, due to an ability to adapt to different types of time series and for being effective at finding a wide range of anomalies. However, the EWMA had the benefit of being faster and more interpretable, but lacked the ability to capture anomalous trends. The ARMA-GARCH was found to have difficulties in finding a good fit to the time series of risk measures, resulting in poor performance, and the HTM was outperformed by the other algorithms in every regard, due to an inability to learn the autoregressive behaviour of the time series., Finansiella institutioner hanterar otaliga portföljer vars risk måste hanteras kontinuerligt, och den stora mängden data som måste processeras gör detta till ett omfattande uppgift. Därför skulle ett system som autonomt kan upptäcka avvikelser i de finansiella portföljernas riskmått, vara av stort värde. I detta syftet undersöks två ekonometriska modeller, ARMA-GARCH och EWMA, samt två maskininlärningsmodeller, LSTM och HTM, för ändamålet att kunna utföra så kallad oövervakad avvikelsedetektering på den strömande tidsseriedata av portföljriskmått. Tre dataset syntetiserades med avkastningar och Value-at-Risk serier, och ett dataset med verkliga Value-at-Risk serier fick handgjorda etiketter till experimenten i denna avhandling. Resultaten visade att LSTM har stor potential i denna domänen, tack vare sin förmåga att anpassa sig till olika typer av tidsserier och för att effektivt lyckas finna varierade sorters anomalier. Däremot så hade EWMA fördelen av att vara den snabbaste och enklaste att tolka, men den saknade förmågan att finna avvikande trender. ARMA-GARCH hade svårigheter med att modellera tidsserier utav riskmått, vilket resulterade i att den preseterade dåligt. HTM blev utpresterad utav de andra algoritmerna i samtliga hänseenden, på grund utav dess oförmåga att lära sig tidsserierna autoregressiva beteende.

Current laboratory-scale fabrication of perovskite solar cells involves the use of toxic solvents in the different fabrication steps. The aim of this research is to find a nontoxic alternative to chlorobenzene used for the deposition of hole transport material (HTM) spiro-OMeTAD. The initial selection of the solvents compatible with industrial manufacturing was performed based on the Hansen solubility model and further verified in a series of solubility tests, because the additives used in the HTM ink, such as lithium bis(trifluoromethanesulfonimidate) (Li-TFSI) and tert-butylpyridine (4-TBP), also have a significant influence on the properties of the final solution. Furthermore, selected solvents were tested on the compatibility with the underlying perovskite layer, which should remain unaffected after the spiro-OMeTAD deposition. A final selection of solvents was tested by the manufacturing of the complete perovskite solar cells. Power conversion efficiency (PCE) and layer quality, as well as possible health issues and environmental concerns, influenced the final selection for future potential industrial processing. The research demonstrated that replacement of chlorobenzene (CB) by p-xylene leads to identical PCEs of the devices, thereby showing that a toxic solvent can be replaced by a nontoxic and industrially compatible one. To prove that the selected solvent is suitable for future large-area coatings, the coatability of the ink was tested in blade-coating deposition. Devices manufactured using blade coating demonstrated identical PCEs to spin-coated devices, which is final proof of the suitability of the selected solvent system., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Novel Aerospace Materials

This Master's Thesis focuses on the recent Cortical Learn-ing Algorithm (CLA), designed for temporal anomaly detection. It is here applied to the problem of anomaly detec-tion in user behavior of web services, which is getting moreand more important in a network security context. CLA is here compared to more traditional state-of-the-art algorithms of anomaly detection: Hidden Markov Models (HMMs) and t-stide (an N-gram-based anomaly detector), which are among the few algorithms compatible withthe online processing constraint of this problem. It is observed that on the synthetic dataset used forthis comparison, CLA performs signicantly better thanthe other two algorithms in terms of precision of the detection. The two other algorithms don't seem to be able tohandle this task at all. It appears that this anomaly de-tection problem (outlier detection in short sequences overa large alphabet) is considerably different from what hasbeen extensively studied up to now.

Organic/Inorganic lead halide perovskite solar cells (PrSCs) have received considerable attention in recent years as the promising materials capable of developing high performance photovoltaic devices due to their high light absorption coefficient, tunable band gap, high carrier mobility, long carrier diffusion length, low temperature processing and abundant elemental constituents. At present, perovskite solar cells have been ushered in a new era of renewed efforts towards  increasing the efficiency and lowering the cost of solar cells. Recently, Perovskite solar cells have reached an efficiency of nearly 20%. This technology combines the benefits of Dye Sensitized Solar Cells (DSSCs), Organic Photovoltaics (OPVs), and thin film solar cells. In this review, we have reported the brief  prior art perspective of perovskite based solar cells, take a cognizance of the current state-of-the-art, highlight the challenges and the opportunities. This review also gives an overview on the impact of different hole transport materials (HTM), electron transport materials (ETM) and the role of Carbon nanomaterials as ETM, HTM and electrode materials.

Transactional memory (TM) has emerged as a promising synchronization abstraction for multi-core architectures. Unlike traditional lock-based approaches, TM shifts the burden of implementing threads synchronization from the programmer to an underlying framework using hardware (HTM) and/or software (STM) components. Although TM can be leveraged to implement transactional data structures (i.e., those where multiple operations are allowed to execute atomically, all-or-nothing, according to the transaction paradigm), its intensive speculation may result in significantly lower performance than the optimized concurrent data structures. This poor performance motivates the need to find other, more effective, alternatives for designing transactional data structures without losing the simple programming abstraction proposed by TM. To do so, we identified three major challenges that need to be addressed to design efficient transactional data structures. The first challenge is composability, namely allowing an atomic execution of two or more data structure operations in the same way as TM provides, but without its high overheads. The second challenge is integration, which enables the execution of data structure operations within generic transactions that may contain other memory- based operations. The last challenge is modeling, which encompasses the necessity of defining a unified formal methodology to reason about the correctness of transactional data structures. In this dissertation, we propose different approaches to address the above challenges. First, we address the composability challenge by introducing an optimistic methodology to effi- ciently convert concurrent data structures into transactional ones. Second, we address the integration challenge by injecting the semantic operations of those transactional data struc- ture into TM frameworks, and by presenting two novel STM algorithms in order to enhance the overall performance of those frameworks. Finally, we address th

Transactional Memory (TM) is a promising paradigm for parallel programming. TM allows a thread to make a series of memory accesses as a single, atomic, transaction, while avoiding deadlocks, livelocks, and other problems commonly associated with lock-based programming. In this paper we explore Hardware support for TM (HTM). In particular, we explore how HTM can efficiently support transactions of nearly unlimited size. For this purpose we propose EcoTM, an economical unbounded HTM that improves the efficiency of conflict detection between very large transactions by activating conflict-detection logic only for potentially-conflicting locations: shared and speculatively modified. EcoTM detects the potentially-conflicting locations automatically, without any program annotations. We evaluate EcoTM performance by comparing it with ideal-lazy HTM, unbounded eager HTM with perfect signatures, and LogTM-SE. Our evaluations show that EcoTM has similar performance as the ideal-lazy HTM, 8.8% better than the eager- perfect HTM, and over 35.7% better than LogTM-SE, on the average., Peer Reviewed, Postprint (published version)

El proyecto consiste en un maquetador de html partiendo de un documento en formato .doc o directamente en htm creado desde windows, el cual seleccionará desde un explorador de archivos que solo permite la subida de documentos windows o htm dependiendo de que hayamos seleccionado y una vez que estemos seguros que documento queremos lo subiremos al servidor, desde donde se trabajará con él y nos lo mostrara ya en el editor de contenido donde podrá crear o modificar un documento htm dentro de un entorno de trabajo con múltiples herramientas de trabajo como modificación de las fuentes, creación y modificación de hipervínculos, creación de tablas, corrector ortográfico, etc...

Most Hardware Transactional Memory (HTM) implementations choose fixed version and conflict management policies at design time. While eager HTM systems store transactional state in-place in memory and resolve conflicts when they are produced, lazy HTM systems buffer the transactional state in specialized hardware and defer the resolution of conflicts until commit time. Each scheme has its strengths and weaknesses, but, unfortunately, both approaches are too inflexible in the way they manage data versioning and transactional contention. Thus, fixed HTM systems may result in a significant performance opportunity loss when they execute complex transactional applications. In this paper, we present DynTM (Dynamically Adaptable HTM), the first fully-flexible HTM system that permits the simultaneous execution of transactions using complementary version and conflict management strategies. In the heart of DynTM is a novel coherence protocol that allows tracking conflicts among eager and lazy transactions. Both the eager and the lazy execution modes of DynTM exhibit very high performance compared to modern HTM systems. For example, the DynTM lazy execution mode implements local commits to improve on previous proposals. In addition, lazy transactions share the majority of hardware support with eager transactions, reducing substantially the hardware cost compared to other lazy HTM systems. By utilizing a simple predictor to decide the best execution mode for each transaction at runtime, DynTM obtains an average speedup of 34% over HTM systems that employ fixed version and conflict management policies., Peer Reviewed, Postprint (published version)

To address the need for a simpler parallel programming model, Transactional Memory (TM) has been developed and promises good parallel performance with easy-to-write parallel code. Unlike lock-based approaches, with TM, programmers do not need to explicitly specify and manage the synchronization among threads. However, programmers simply mark code segments as transactions, and the TM system manages the concurrency control for them. TM can be implemented either in software (STM) or hardware (HTM). STMs are more flexible but suffer from serious performance overheads whereas HTMs are faster but limited due to hardware space constrains. We present an implementation of a HTM system, based on an existing protocol (Scalable-TCC), over a full-system simulator. We provide a memory system that allows for a configurable number of cache entries, associativity, cache-line size, and all the access timings in the memory hierarchy. Combined with a powerful statistics system that provides all the necessary information to extract conclusions from the transactional executions. We evaluate our HTM system using applications that cover a wide range of transactional behaviours and demonstrate that it scales efficiently up to 32 processors.

Black liquors are presently combusted in recovery boilers where the inorganic cooking chemicals are recovered and the energy in the organic material is converted to steam and electricity. A new technology, developed by Chemrec AB, is black liquor gasification (BLG). BLG has more to offer compared to the recovery boiler process, in terms of on-site generation of electric power, liquid fuel and process chemicals. A prerequisite for both optimization of existing processes and the commercialization of BLG is better understanding of the physical and chemical processes involved including interactions with the refractory lining. The chemistry in the BLG process is very complex and to minimize extensive and expensive time-consuming studies otherwise required accurate and reliable model descriptions are needed for a full understanding of most chemical and physical processes as well as for up-scaling of the new BLG processes. However, by using these calculated model results in practice, the errors in the state of the art thermochemical data have to be considered. An extensive literature review was therefore performed to update the data needed for unary, binary and higher order systems. The results from the review reviled that there is a significant range of uncertainty for several condensed phases and a few gas species. This resulted in experimental re-determinations of the binary phase diagrams sodium carbonate-sodium sulfide (Na2CO3-Na2S) and sodium sulfate-sodium sulfide (Na2SO4-Na2S) using High Temperature Microscopy (HTM), High Temperature X-ray Diffraction (HT-XRD) and Differential Thermal Analysis (DTA). For the Na2CO3-Na2S system, measurements were carried out in dry inert atmosphere at temperatures from 25 to 1200 °C. To examine the influence of pure CO2 atmosphere on the melting behavior, HTM experiments in the same temperature interval were made. The results include re-determination of liquidus curves, in the Na2CO3 rich area, melting points of the pure components

Aim of this thesis is to analyze Dc-Dc converters by using the techniques of Linear Periodic Time varying (LTP) systems to estimate the amount of subharmonics injected in the load. Dc-Dc converters are used to transform a Dc input to a Dc output of different voltage. In this thesis we study in particular the so called "switch mode" converters. In this kind of devices the conversion is obtained by using fast commutations of (at least) two switches. Due to the discrete switch-positions these converters are considered a typical example of hybrid systems. Linear models with fixed coefficients (LTI system) give a description of the system inadequate to predict and to analyze harmonic effects, while linear models with coefficients that vary periodically, namely LTP system, can be used effectively to this aim. We use therefore a Linear Time Periodic (LTP) system to describe the converter. This kind of description in much more accurate but the model and the tools used to study it are more complex. In the thesis we first introduce the LTP system theory and its main results. In particular we introduce the concept of Harmonic Transfer Function (HTF). A LTP model for a Dc-Dc converter is then derived and it is shown that this model accurately describes the response of the converter. Furthermore this LTP model is used to analyze the open and closed loop behavior of the system. It is shown that the linear model estimates correctly the amplitude of the subharmonics in the output. The thesis has been developed at the Automatic Control Department, Lund University, Sweden under the supervision of Andreas Wernrud and Anders Rantzer. The Italian supervisor of this thesis is Giorgio Picci, Dipartimento di Ingegneria dell' Informazione, Università degli studi di Padova, Italy