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- Andersson Ersman, Peter, et al.
(author)
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Screen printed digital circuits based on vertical organicelectrochemical transistors
- 2017
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In: Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 2
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Journal article (peer-reviewed)abstract
- Vertical organic electrochemical transistors (OECTs) have been manufactured solely using screenprinting. The OECTs are based on PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid)), which defines the active material for both the transistor channel and the gateelectrode. The resulting vertical OECT devices and circuits exhibit low-voltage operation, relativelyfast switching, small footprint and high manufacturing yield; the last three parameters are explainedby the reliance of the transistor configuration on a robust structure in which the electrolyte verticallybridges the bottom channel and the top gate electrode. Two different architectures of the verticalOECT have been manufactured, characterized and evaluated in parallel throughout this report. Inaddition to the experimental work, SPICE models enabling simulations of standalone OECTs andOECT-based circuits have been developed. Our findings may pave the way for fully integrated, lowvoltageoperating and printed signal processing systems integrated with e.g. printed batteries, solarcells, sensors and communication interfaces. Such technology can then serve a low-cost basetechnology for the internet of things, smart packaging and home diagnostics applications.
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| 4. |
- Oosterhuis, Wytze P., et al.
(author)
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The use of error and uncertainty methods in the medical laboratory
- 2018
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In: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 56:2, s. 209-219
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Journal article (peer-reviewed)abstract
- Error methods - compared with uncertainty methods - offer simpler, more intuitive and practical procedures for calculating measurement uncertainty and conducting quality assurance in laboratory medicine. However, uncertainty methods are preferred in other fields of science as reflected by the guide to the expression of uncertainty in measurement. When laboratory results are used for supporting medical diagnoses, the total uncertainty consists only partially of analytical variation. Biological variation, pre- and postanalytical variation all need to be included. Furthermore, all components of the measuring procedure need to be taken into account. Performance specifications for diagnostic tests should include the diagnostic uncertainty of the entire testing process. Uncertainty methods may be particularly useful for this purpose but have yet to show their strength in laboratory medicine. The purpose of this paper is to elucidate the pros and cons of error and uncertainty methods as groundwork for future consensus on their use in practical performance specifications. Error and uncertainty methods are complementary when evaluating measurement data.
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| 5. |
- Sandberg, Andreas, 1984-
(author)
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Understanding Multicore Performance : Efficient Memory System Modeling and Simulation
- 2014
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Doctoral thesis (other academic/artistic)abstract
- To increase performance, modern processors employ complex techniques such as out-of-order pipelines and deep cache hierarchies. While the increasing complexity has paid off in performance, it has become harder to accurately predict the effects of hardware/software optimizations in such systems. Traditional microarchitectural simulators typically execute code 10 000×–100 000× slower than native execution, which leads to three problems: First, high simulation overhead makes it hard to use microarchitectural simulators for tasks such as software optimizations where rapid turn-around is required. Second, when multiple cores share the memory system, the resulting performance is sensitive to how memory accesses from the different cores interleave. This requires that applications are simulated multiple times with different interleaving to estimate their performance distribution, which is rarely feasible with today's simulators. Third, the high overhead limits the size of the applications that can be studied. This is usually solved by only simulating a relatively small number of instructions near the start of an application, with the risk of reporting unrepresentative results.In this thesis we demonstrate three strategies to accurately model multicore processors without the overhead of traditional simulation. First, we show how microarchitecture-independent memory access profiles can be used to drive automatic cache optimizations and to qualitatively classify an application's last-level cache behavior. Second, we demonstrate how high-level performance profiles, that can be measured on existing hardware, can be used to model the behavior of a shared cache. Unlike previous models, we predict the effective amount of cache available to each application and the resulting performance distribution due to different interleaving without requiring a processor model. Third, in order to model future systems, we build an efficient sampling simulator. By using native execution to fast-forward between samples, we reach new samples much faster than a single sample can be simulated. This enables us to simulate multiple samples in parallel, resulting in almost linear scalability and a maximum simulation rate close to native execution.
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| 6. |
- Sarris, Theodore E., et al.
(author)
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Daedalus MASE (mission assessment through simulation exercise): A toolset for analysis of in situ missions and for processing global circulation model outputs in the lower thermosphere-ionosphere
- 2023
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In: Frontiers in Astronomy and Space Sciences. - : Frontiers Media SA. - 2296-987X. ; 9
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Journal article (peer-reviewed)abstract
- Daedalus MASE (Mission Assessment through Simulation Exercise) is an open-source package of scientific analysis tools aimed at research in the Lower Thermosphere-Ionosphere (LTI). It was created with the purpose to assess the performance and demonstrate closure of the mission objectives of Daedalus, a mission concept targeting to perform in-situ measurements in the LTI. However, through its successful usage as a mission-simulator toolset, Daedalus MASE has evolved to encompass numerous capabilities related to LTI science and modeling. Inputs are geophysical observables in the LTI, which can be obtained either through in-situ measurements from spacecraft and rockets, or through Global Circulation Models (GCM). These include ion, neutral and electron densities, ion and neutral composition, ion, electron and neutral temperatures, ion drifts, neutral winds, electric field, and magnetic field. In the examples presented, these geophysical observables are obtained through NCAR’s Thermosphere-Ionosphere-Electrodynamics General Circulation Model. Capabilities of Daedalus MASE include: 1) Calculations of products that are derived from the above geophysical observables, such as Joule heating, energy transfer rates between species, electrical currents, electrical conductivity, ion-neutral collision frequencies between all combinations of species, as well as height-integrations of derived products. 2) Calculation and cross-comparison of collision frequencies and estimates of the effect of using different models of collision frequencies into derived products. 3) Calculation of the uncertainties of derived products based on the uncertainties of the geophysical observables, due to instrument errors or to uncertainties in measurement techniques. 4) Routines for the along-orbit interpolation within gridded datasets of GCMs. 5) Routines for the calculation of the global coverage of an in situ mission in regions of interest and for various conditions of solar and geomagnetic activity. 6) Calculations of the statistical significance of obtaining the primary and derived products throughout an in situ mission’s lifetime. 7) Routines for the visualization of 3D datasets of GCMs and of measurements along orbit. Daedalus MASE code is accompanied by a set of Jupyter Notebooks, incorporating all required theory, references, codes and plotting in a user-friendly environment. Daedalus MASE is developed and maintained at the Department for Electrical and Computer Engineering of the Democritus University of Thrace, with key contributions from several partner institutions.
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| 7. |
- Woll, Petter S, et al.
(author)
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Myelodysplastic Syndromes Are Propagated by Rare and Distinct Human Cancer Stem Cells In Vivo.
- 2014
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In: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 25:6, s. 794-808
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Journal article (peer-reviewed)abstract
- Evidence for distinct human cancer stem cells (CSCs) remains contentious and the degree to which different cancer cells contribute to propagating malignancies in patients remains unexplored. In low- to intermediate-risk myelodysplastic syndromes (MDS), we establish the existence of rare multipotent MDS stem cells (MDS-SCs), and their hierarchical relationship to lineage-restricted MDS progenitors. All identified somatically acquired genetic lesions were backtracked to distinct MDS-SCs, establishing their distinct MDS-propagating function in vivo. In isolated del(5q)-MDS, acquisition of del(5q) preceded diverse recurrent driver mutations. Sequential analysis in del(5q)-MDS revealed genetic evolution in MDS-SCs and MDS-progenitors prior to leukemic transformation. These findings provide definitive evidence for rare human MDS-SCs in vivo, with extensive implications for the targeting of the cells required and sufficient for MDS-propagation.
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| 8. |
- Abrahamsson, Tobias, et al.
(author)
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Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol.
- 2019
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In: Frontiers in chemistry. - : Frontiers Media SA. - 2296-2646. ; 7
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Journal article (peer-reviewed)abstract
- In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.
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| 9. |
- Ahlström, Christer, et al.
(author)
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Fit-for-duty test for estimation of drivers sleepiness level: Eye movements improve the sleep/wake predictor
- 2013
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In: Transportation Research Part C. - : Elsevier. - 0968-090X .- 1879-2359. ; 26, s. 20-32
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Journal article (peer-reviewed)abstract
- Driver sleepiness contributes to a considerable proportion of road accidents, and a fit-for-duty test able to measure a drivers sleepiness level might improve traffic safety. The aim of this study was to develop a fit-for-duty test based on eye movement measurements and on the sleep/wake predictor model (SWP, which predicts the sleepiness level) and evaluate the ability to predict severe sleepiness during real road driving. Twenty-four drivers participated in an experimental study which took place partly in the laboratory, where the fit-for-duty data were acquired, and partly on the road, where the drivers sleepiness was assessed. A series of four measurements were conducted over a 24-h period during different stages of sleepiness. Two separate analyses were performed; a variance analysis and a feature selection followed by classification analysis. In the first analysis it was found that the SWP and several eye movement features involving anti-saccades, pro-saccades, smooth pursuit, pupillometry and fixation stability varied significantly with different stages of sleep deprivation. In the second analysis, a feature set was determined based on floating forward selection. The correlation coefficient between a linear combination of the acquired features and subjective sleepiness (Karolinska sleepiness scale, KSS) was found to be R = 0.73 and the correct classification rate of drivers who reached high levels of sleepiness (KSS andgt;= 8) in the subsequent driving session was 82.4% (sensitivity = 80.0%, specificity = 84.2% and AUC = 0.86). Future improvements of a fit-for-duty test should focus on how to account for individual differences and situational/contextual factors in the test, and whether it is possible to maintain high sensitive/specificity with a shorter test that can be used in a real-life environment, e.g. on professional drivers.
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