| 1. |
- Andersson Ersman, Peter, et al.
(author)
-
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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| 2. |
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| 3. |
- Oosterhuis, Wytze P., et al.
(author)
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The use of error and uncertainty methods in the medical laboratory
- 2018
-
In: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 56:2, s. 209-219
-
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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| 4. |
- Abrahamsson, Tobias, et al.
(author)
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Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol.
- 2019
-
In: Frontiers in chemistry. - : Frontiers Media SA. - 2296-2646. ; 7
-
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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| 5. |
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| 6. |
- Ansari, David, et al.
(author)
-
Pancreatic cancer and thromboembolic disease, 150 years after Trousseau.
- 2015
-
In: HepatoBiliary surgery and nutrition. - 2304-3881. ; 4:5, s. 325-335
-
Research review (peer-reviewed)abstract
- The connection between pancreatic cancer and venous thrombosis has been discussed for almost 150 years. The exact pathophysiological mechanisms are still partly understood, but it is known that pancreatic cancer induces a prothrombotic and hypercoagulable state and genetic events involved in neoplastic transformation (e.g., KRAS, c-MET, p53), procoagulant factors [e.g., tissue factor (TF), platelet factor 4 (PF4), plasminogen activator inhibitor type 1 (PAI-1)], mucin production (e.g., through activation of P- and L-selectin) and pro-inflammatory factors [e.g., cytokines, cyclooxygenase-2 (COX-2)] may be implicated. Also pancreatitis, both acute and chronic, is associated with increased risk of venous thrombosis, but in this circumstance a direct inflammatory process may be more important. This article discusses the incidence, treatment and outcome of venous thromboembolism (VTE) complicating pancreatic disease, with special emphasis on new knowledge obtained during the last fifteen years.
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| 7. |
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| 8. |
- Baliakas, Panagiotis, et al.
(author)
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Not all IGHV3-21 chronic lymphocytic leukemias are equal: prognostic considerations.
- 2015
-
In: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 125:5, s. 856-859
-
Journal article (peer-reviewed)abstract
- An unresolved issue in chronic lymphocytic leukemia (CLL) is whether IGHV3-21 gene usage, in general, or the expression of stereotyped B-cell receptor immunoglobulin defining subset #2 (IGHV3-21/IGLV3-21), in particular, determines outcome for IGHV3-21-utilizing cases. We reappraised this issue in 8593 CLL patients of whom 437 (5%) used the IGHV3-21 gene with 254/437 (58%) classified as subset #2. Within subset #2, immunoglobulin heavy variable (IGHV)-mutated cases predominated, whereas non-subset #2/IGHV3-21 was enriched for IGHV-unmutated cases (P = .002). Subset #2 exhibited significantly shorter time-to-first-treatment (TTFT) compared with non-subset #2/IGHV3-21 (22 vs 60 months, P = .001). No such difference was observed between non-subset #2/IGHV3-21 vs the remaining CLL with similar IGHV mutational status. In conclusion, IGHV3-21 CLL should not be axiomatically considered a homogeneous entity with adverse prognosis, given that only subset #2 emerges as uniformly aggressive, contrasting non-subset #2/IGVH3-21 patients whose prognosis depends on IGHV mutational status as the remaining CLL.
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| 9. |
- Bridel, Claire, et al.
(author)
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Diagnostic Value of Cerebrospinal Fluid Neurofilament Light Protein in Neurology : A Systematic Review and Meta-analysis
- 2019
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In: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:9, s. 1035-1048
-
Research review (peer-reviewed)abstract
- Importance Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date.Objectives To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions.Data Sources PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC.Study Selection Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex.Data Extraction and Synthesis Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept.Main Outcome and Measure The cNfL levels adjusted for age and sex across diagnoses.Results Data were collected for 10 059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n = 2795), dementias and predementia stages (n = 4284), parkinsonian disorders (n = 984), and HC (n = 1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes.Conclusions and Relevance These data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.
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| 10. |
- Buggert, Marcus, et al.
(author)
-
Limited immune surveillance in lymphoid tissue by cytolytic CD4+ T cells during health and HIV disease
- 2018
-
In: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7374. ; 14:4
-
Journal article (peer-reviewed)abstract
- CD4+ T cells subsets have a wide range of important helper and regulatory functions in the immune system. Several studies have specifically suggested that circulating effector CD4+ T cells may play a direct role in control of HIV replication through cytolytic activity or autocrine β-chemokine production. However, it remains unclear whether effector CD4+ T cells expressing cytolytic molecules and β-chemokines are present within lymph nodes (LNs), a major site of HIV replication. Here, we report that expression of β-chemokines and cytolytic molecules are enriched within a CD4+ T cell population with high levels of the T-box transcription factors T-bet and eomesodermin (Eomes). This effector population is predominately found in peripheral blood and is limited in LNs regardless of HIV infection or treatment status. As a result, CD4+ T cells generally lack effector functions in LNs, including cytolytic capacity and IFNγ and β-chemokine expression, even in HIV elite controllers and during acute/early HIV infection. While we do find the presence of degranulating CD4+ T cells in LNs, these cells do not bear functional or transcriptional effector T cell properties and are inherently poor to form stable immunological synapses compared to their peripheral blood counterparts. We demonstrate that CD4+ T cell cytolytic function, phenotype, and programming in the peripheral blood is dissociated from those characteristics found in lymphoid tissues. Together, these data challenge our current models based on blood and suggest spatially and temporally dissociated mechanisms of viral control in lymphoid tissues.
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| 11. |
- Bächle, Susanna M., et al.
(author)
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Elevated levels of iNKT cell and NK cell activation correlate with disease progression in HIV-1 and HIV-2 infections
- 2016
-
In: AIDS. - 0269-9370. ; 30:11, s. 1713-1722
-
Journal article (peer-reviewed)abstract
- OBJECTIVE:: In this study we aimed to investigate the frequency and activation of invariant natural killer T (iNKT) cells and natural killer (NK) cells among HIV-1, HIV-2, or dually HIV-1/HIV-2 (HIV-D)-infected individuals, in relation to markers of disease progression. DESIGN:: Whole blood samples were collected from treatment-naïve HIV-1 (n?=?23), HIV-2 (n?=?34) and HIV-D (n?=?11) infected individuals, as well as HIV-seronegative controls (n?=?25), belonging to an occupational cohort in Guinea-Bissau. METHODS:: Frequencies and activation levels of iNKT and NK cell subsets were analysed using multi-colour flow cytometry and results were related to HIV-status, CD4+ T cell levels, viral load, and T cell activation. RESULTS:: HIV-1, HIV-D, and viremic HIV-2 individuals had lower numbers of CD4+ iNKT cells in circulation compared to seronegative controls. Numbers of CD56 NK cells were also reduced in HIV-infected individuals as compared to control subjects. Notably, iNKT cell and NK cell activation levels, assessed by CD38 expression, were increased in HIV-1 and HIV-2 single, as well as dual, infections. HIV-2 viremia was associated with elevated activation levels in CD4+ iNKT cells, CD56 and CD56 NK cells, as compared to aviremic HIV-2 infection. Additionally, disease markers such as CD4+ T cell percentages, viral load, and CD4+ T cell activation were associated with CD38 expression levels of both iNKT and NK cells, which activation levels also correlated with each other. CONCLUSIONS:: Our data indicate that elevated levels of iNKT cell and NK cell activation are associated with viremia and disease progression markers in both HIV-1 and HIV-2 infections.
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| 12. |
- Chong, Michelle, et al.
(author)
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Local voltage control of an inverter-based power distribution network with a class of slope-restricted droop controllers
- 2019
-
In: IFAC PAPERSONLINE. - : ELSEVIER. - 2405-8963. ; , s. 163-168
-
Conference paper (peer-reviewed)abstract
- Motivated by the environmental and economical benefits of using renewable energy, we consider the problem of regulating the voltage of a power distribution network in a line configuration where each customer is equipped with an inverter. The substation at the head of the line determines the nominal voltage level which is communicated to each customer in the distribution line. The voltage level of each customer is regulated by an inverter which generates reactive power according to our class of droop controllers satisfying the sloperestriction property. This paper provides a sufficient condition for regulating the customers' voltage level within a desired band, which depends on the properties of the distribution line (line impedances) and the droop controller employed. This is achieved when only the upper bound of all the customers' net power usage is known, thereby preserving the privacy of each customer. Simulation studies are performed on a benchmark model for a distribution system with renewable sources.
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| 13. |
- Chong, Michelle, et al.
(author)
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Voltage regulation of a power distribution network in a radial configuration with a class of sector-bounded droop controllers
- 2019
-
In: Proceedings of the IEEE Conference on Decision and Control. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 3515-3520
-
Conference paper (peer-reviewed)abstract
- We consider the problem of voltage regulation for a power distribution network where each inverter-equipped customer is connected sequentially with the sub-station at the head of the line. The substation dictates the desired voltage and transmits the reference voltage to each inverter in the distribution line. The inverter generates reactive power using our modified droop control law, which regulates the voltage level by influencing the power flow in the line, described by the DistFlow model. This paper provides conditions on the distribution line (the line impedances), the droop control law employed, and the nominal voltage level at the substation such that the each customer's voltage level are within a desired margin, when only the bound on the customers' overall power consumption is known. Thereby preserving the privacy of each customer's net power usage. We have also widened the choice of droop functions by only requiring them to be sector bounded. Simulation studies are provided to illustrate our results.
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| 14. |
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| 15. |
- Giraldo, Jairo, et al.
(author)
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A Survey of Physics-Based Attack Detection in Cyber-Physical Systems
- 2018
-
In: ACM Computing Surveys. - : ASSOC COMPUTING MACHINERY. - 0360-0300 .- 1557-7341. ; 51:4
-
Journal article (peer-reviewed)abstract
- Monitoring the "physics" of cyber-physical systems to detect attacks is a growing area of research. In its basic form, a security monitor creates time-series models of sensor readings for an industrial control system and identifies anomalies in these measurements to identify potentially false control commands or false sensor readings. In this article, we review previous work on physics-based anomaly detection based on a unified taxonomy that allows us to identify limitations and unexplored challenges and to propose new solutions.
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| 16. |
- Järver, Peter, et al.
(author)
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Single-Stranded Nucleic Acids Regulate TLR3/4/7 Activation through Interference with Clathrin-Mediated Endocytosis
- 2018
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
-
Journal article (peer-reviewed)abstract
- Recognition of nucleic acids by endosomal Toll-like receptors (TLR) is essential to combat pathogens, but requires strict control to limit inflammatory responses. The mechanisms governing this tight regulation are unclear. We found that single-stranded oligonucleotides (ssON) inhibit endocytic pathways used by cargo destined for TLR3/4/7 signaling endosomes. Both ssDNA and ssRNA conferred the endocytic inhibition, it was concentration dependent, and required a certain ssON length. The ssON-mediated inhibition modulated signaling downstream ofTLRs that localized within the affected endosomal pathway. We further show that injection of ssON dampens dsRNA-mediated inflammatory responses in the skin of non-human primates. These studies reveal a regulatory role for extracellular ssON in the endocytic uptake of TLR ligands and provide a mechanistic explanation of their immunomodulation. The identified ssON-mediated interference of endocytosis (SOMIE) is a regulatory process that temporarily dampens TLR3/4/7 signaling, thereby averting excessive immune responses.
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| 17. |
- Keshmiri, Vahid, et al.
(author)
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A Silicon-Organic Hybrid Voltage Equalizer for Supercapacitor Balancing
- 2017
-
In: IEEE Journal on Emerging and Selected Topics in Circuits and Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2156-3357 .- 2156-3365. ; 7:1, s. 114-122
-
Journal article (peer-reviewed)abstract
- Cell voltage equalizers are an important part in electric energy storage systems comprising series-connected cells, for example, supercapacitors. Hybrid electronics with silicon chips and printed devices enables electronic systems with moderate performance and low cost. This paper presents a silicon-organic hybrid voltage equalizer to balance and protect series-connected supercapacitor cells during charging. Printed organic electrochemical transistors with conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) are utilized to bypass excess current when the supercapacitor cells are fully charged to desired voltages. In this study, low-cost silicon microcontrollers (ATtiny85) are programmed to sense voltages across the supercapacitor cells and control the organic electrochemical transistors to bypass charging current when the voltages exceed 1 V. Experimental results show that the hybrid equalizer with the organic electrochemical transistors works in dual-mode, switched-transistor mode or constant-resistor mode, depending on the charging current applied (0.3-100 mA). With the voltage equalizer, capacitors are charged equally regardless of their capacitances. This work demonstrates a low-cost hybrid solution for supercapacitor balancing modules at large-scale packs.
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| 18. |
- Keshmiri, Vahid, et al.
(author)
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The applications of OECTs in supercapacitor balancing circuits
- 2016
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In: 2016 7th International Conference on Computer Aided Design for Thin-Film Transistor Technologies (CAD-TFT). - : IEEE. - 9781509026876 ; , s. 23-23
-
Conference paper (peer-reviewed)abstract
- In this paper, we investigate using OECTs in differential amplifiers and cell voltage equalizers for supercapacitor balancing circuits. The differential amplifier based on OECTs can sense voltage difference and the voltage equalizer consisting of a microcontroller and OECTs can be used to charge supercapacitors to desired voltages.
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| 19. |
- Kintzler, Florian, et al.
(author)
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Large Scale Rollout of Smart Grid Services
- 2018
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In: 2018 GLOBAL INTERNET OF THINGS SUMMIT (GIOTS). - : IEEE. ; , s. 215-221
-
Conference paper (peer-reviewed)abstract
- In the domain of energy automation, where a massive number of software-based IoT services interact with a complex dynamic system, processes for software installation and software update become more important and more complex. These processes have to ensure that the dependencies on all layers are fulfilled, including dependencies arising due to the energy system controlled by IT components being a hidden communication channel between these components. In addition, the processes have to be resilient against faults in and attacks to both the energy grid and the communication network. The ERA-Net funded project LarGo! aims at developing and testing processes for the large scale rollout of software applications in the power grid domain as well as the user domain. This article describes a work in progress and the project's roadmap to solve the technical issues. It investigates the problems that arise from the interlocking of the two networks - the power grid and the communication network. Based on this analysis a first set of requirements for a rollout process in such a Smart Grid is derived and the chosen approach to verify the resilience of the developed processes under research is described.
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| 20. |
- Lindberg, David, 1986, et al.
(author)
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Steady-state and time-resolved Thioflavin-T fluorescence can report on morphological differences in amyloid fibrils formed by A beta(1-40) and A beta(1-42)
- 2015
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In: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 458:2, s. 418-423
-
Journal article (peer-reviewed)abstract
- Thioflavin-T (ThT) is one of the most commonly used dyes for amyloid detection, but the origin of its fluorescence enhancement is not fully understood. Herein we have characterised the ThT fluorescence response upon binding to the A beta(1-40) and A beta(1-42) variants of the Alzheimer's-related peptide amyloid-beta, in order to explore how the photophysical properties of this dye relates to structural and morphological properties of two amyloid fibril types formed by peptides with a high degree of sequence homology. We show that the steady-state ThT fluorescence is 1.7 times more intense with A beta(1-40) compared to A beta(1-42) fibrils in concentration matched samples prepared under quiescent conditions. By measuring the excited state lifetime of bound ThT, we also demonstrate a distinct difference between the two fibril isoforms, with A beta(1-42) fibrils producing a longer ThT fluorescence lifetime compared to A beta(140). The substantial steady-state intensity difference is therefore not explained by differences in fluorescence quantum yield. Further, we find that the ThT fluorescence intensity, but not the fluorescence lifetime, is dependent on the fibril preparation method (quiescent versus agitated conditions). We therefore propose that the fluorescence lifetime is inherent to each isoform and sensitively reports on fibril microstructure in the protofilament whereas the total fluorescence intensity relates to the amount of exposed beta-sheet in the mature A beta fibrils and hence to differences in their morphology. Our results highlight the complexity of ThT fluorescence, and demonstrate its extended use in amyloid fibril characterisation.
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| 21. |
- Milosevic, Jezdimir, et al.
(author)
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Quantifying the Impact of Cyber-Attack Strategies for Control Systems Equipped with an Anomaly Detector
- 2018
-
In: 2018 European Control Conference, ECC 2018. - : Institute of Electrical and Electronics Engineers (IEEE). - 9783952426982 ; , s. 331-337
-
Conference paper (peer-reviewed)abstract
- Risk assessment is an inevitable step in the implementation of cost-effective security strategies for control systems. One of the difficulties of risk assessment is to estimate the impact cyber-attacks may have. This paper proposes a framework to estimate the impact of several cyber-attack strategies against a dynamical control system equipped with an anomaly detector. In particular, we consider denial of service, sign alternation, rerouting, replay, false data injection, and bias injection attack strategies. The anomaly detectors we consider are stateless, cumulative sum, and multivariate exponentially weighted moving average detectors. As a measure of the attack impact, we adopt the infinity norm of critical states after a fixed number of time steps. For this measure and the aforementioned anomaly detectors, we prove that the attack impact for all of the attack strategies can be reduced to the problem of solving a set of convex minimization problems. Therefore, the exact value of the attack impact can be obtained easily. We demonstrate how our modeling framework can be used for risk assessment on a numerical example.
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| 22. |
- Sandberg, Andreas, et al.
(author)
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Full speed ahead : Detailed architectural simulation at near-native speed
- 2015
-
In: Proc. 18th International Symposium on Workload Characterization. - : IEEE Computer Society. - 9781509000883 ; , s. 183-192
-
Conference paper (peer-reviewed)abstract
- Cycle-level microarchitectural simulation is the defacto standard to estimate performance of next-generation platforms. Unfortunately, the level of detail needed for accurate simulation requires complex, and therefore slow, simulation models that run at speeds that are thousands of times slower than native execution. With the introduction of sampled simulation, it has become possible to simulate only the key, representative portions of a workload in a reasonable amount of time and reliably estimate its overall performance. These sampling methodologies provide the ability to identify regions for detailed execution, and through microarchitectural state checkpointing, one can quickly and easily determine the performance characteristics of a workload for a variety of microarchitectural changes. While this strategy of sampling simulations to generate checkpoints performs well for static applications, more complex scenarios involving hardware-software co-design (such as co-optimizing both a Java virtual machine and the microarchitecture it is running on) cause this methodology to break down, as new microarchitectural checkpoints are needed for each memory hierarchy configuration and software version. Solutions are therefore needed to enable fast and accurate simulation that also address the needs of hardware-software co-design and exploration. In this work we present a methodology to enhance checkpoint-based sampled simulation. Our solution integrates hardware virtualization to provide near-native speed, virtualized fast-forwarding to regions of interest, and parallel detailed simulation. However, as we cannot warm the simulated caches during virtualized fast-forwarding, we develop a novel approach to estimate the error introduced by limited cache warming, through the use of optimistic and pessimistic warming simulations. Using virtualized fast-forwarding (which operates at 90% of native speed on average), we demonstrate a parallel sampling simulator that can be used to accurately estimate the IPC of standard workloads with an average error of 2.2% while still reaching an execution rate of 2.0 GIPS (63% of native) on average. Additionally, we demonstrate that our parallelization strategy scales almost linearly and simulates one core at up to 93% of its native execution rate, 19,000x faster than detailed simulation, while using 8 cores.
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| 23. |
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| 24. |
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| 25. |
- Sandberg, Jacob, et al.
(author)
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Relating Experienced To Recalled breathlessness Observational (RETRO) study : A prospective study using a mobile phone application
- 2019
-
In: BMJ Open Respiratory Research. - : BMJ Publishing Group. - 2052-4439. ; 6:1
-
Journal article (peer-reviewed)abstract
- Background: Breathlessness, the subjective sensation of breathing discomfort, is common and appears in the daily life of people with cardiorespiratory diseases. Physicians often rely on patient's history based on symptom recall. The relation between recalled and experienced breathlessness is still poorly understood. This paper presents the protocol for a study primarily aimed at evaluating the relationship between experienced breathlessness and (1) recalled breathlessness and (2) predicted future breathlessness. Methods: A mobile phone application will be used to collect data during daily life. Medically stable participants, ≥18 years of age with mean daily breathlessness of Numerical Rating Scale (NRS) 3/10 and able to use a mobile phone with internet will rate their breathlessness intensity on a 0-10 NRS prompted the user several times daily for 1 week. Participants will recall their breathlessness each day and week. Multivariable random effects regression models will be used for statistical analyses. Results: Results of the study will be submitted for publication in peer-reviewed journals and presented at relevant conferences. Discussion: This protocol describes a study aimed at investigating previously unknown areas of the experience and recall of breathlessness using a new method of data collection. © 2019 Author(s).
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| 26. |
- Sandberg, Joakim, 1979, et al.
(author)
-
Sustainable Investment: Mobilizing Financial Capital for Sustainable Development
- 2019
-
In: Decent Work and Economic Growth: Encyclopedia of the UN Sustainable Development Goals / [ed] Walter Leal Filho, Anabela Marisa Azul, Luciana Brandli, Pinar Gökcin Özuyar, Tony Wall. - Cham : Springer. - 2523-7403 .- 2523-7411. - 9783319710587
-
Book chapter (peer-reviewed)
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| 27. |
- Sandberg, Jacob, et al.
(author)
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Validation of the Dyspnea Exertion Scale of Breathlessness in People With Life-Limiting Illness
- 2018
-
In: Journal of Pain and Symptom Management. - : Elsevier BV. - 0885-3924. ; 56:3, s. 2-435
-
Journal article (peer-reviewed)abstract
- Background: Although chronic breathlessness is common in life-limiting illnesses, validated feasible instruments to measure functional impact of the symptom in this population are scarce. We aimed to validate the Dyspnea Exertion Scale (DES) compared with the modified Medical Research Council (mMRC) breathlessness scale for test-retest reliability, concurrent validity, and responsiveness in people with life-limiting illness. Methods: A total of 188 participants, 66% males, with chronic breathlessness, mostly (70%) because of chronic pulmonary disease (chronic obstructive pulmonary disease) self-reported evening scores of mMRC, DES, Numerical Rating Scale (NRS), and Eastern Cooperative Oncology Group during nine days. Results: About 44% (n = 81) scored the highest score on mMRC indicating a ceiling effect not seen with DES. Both scales had moderate-to-good test-retest agreement (89% DES; 84% mMRC; P < 0.001 for both). Analyses for concurrent validity showed that higher DES and mMRC scores were correlated with higher NRS breathlessness intensity scores and Eastern Cooperative Oncology Group scores throughout the nine days. In longitudinal analyses, DES (r = 0.30; P < 0.001) was more responsive to change in NRS score during nine days than the mMRC (r = 0.16; P = 0.03). Conclusion: Compared with mMRC, DES had comparable or better measurement properties in terms of test-retest reliability and concurrent validity and could be used as a discriminative tool in this population, but both scales are too insensitive to change to be used as an outcome in clinical trials.
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| 28. |
- Sandberg, Linda, et al.
(author)
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Job strain : a cross-sectional survey of dementia care specialists and other staff in Swedish home care services
- 2018
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In: Journal of Multidisciplinary Healthcare. - : Dove Mecial Press. - 1178-2390. ; 11, s. 255-266
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Journal article (peer-reviewed)abstract
- Introduction: An increasing number of older persons worldwide live at home with various functional limitations such as dementia. So, home care staff meet older persons with extensive, complex needs. The staff's well-being is crucial because it can affect the quality of their work, although literature on job strain among home care staff is limited.Aim: To describe perceived job strain among home care staff and to examine correlations between job strain, personal factors, and organizational factors.Methods: The study applied a cross-sectional survey design. Participants were dementia care specialists who work in home care (n=34) and other home care staff who are not specialized in dementia care (n=35). The Strain in Dementia Care Scale (SDCS) and Creative Climate Questionnaire instruments and demographic variables were used. Descriptive and inferential statistics (including regression modeling) were applied. The regional ethical review board approved the study.Results: Home care staff perceived job strain - particularly because they could not provide what they perceived to be necessary care. Dementia care specialists ranked job strain higher (m=5.71) than other staff members (m=4.71; p=0.04). Job strain (for total score and for all five SDCS factors) correlated with being a dementia care specialist. Correlations also occurred between job strain for SDCS factor 2 (difficulties understanding and interpreting) and not having Swedish as first language and SDCS factor 5 (lack of recognition) and stagnated organizational climate.Conclusion: The study indicates that home care staff and particularly dementia care specialists perceived high job strain. Future studies are needed to confirm or reject findings from this study.
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| 29. |
- Umsonst, David, et al.
(author)
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A game-theoretic approach for choosing a detector tuning under stealthy sensor data attacks
- 2018
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In: 2018 IEEE CONFERENCE ON DECISION AND CONTROL (CDC). - : IEEE. - 9781538613955 ; , s. 5975-5981
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Conference paper (peer-reviewed)abstract
- A Stackelberg game framework is presented to choose the detector tuning for a general detector class under stealthy sensor attacks. In this framework, the defender acts as a leader and chooses a detector tuning, while the attacker will follow with a stealthy attack adjusted to this tuning. The tuning chosen is optimal with respect to the cost induced by the false alarms and the attack impact. We can show that under some practical assumptions the Stackelberg game always has a solution and we state two different sufficient conditions for the uniqueness of the solution. Interestingly, these conditions show that the attack impact does not have to be a convex function. An illustrative attack scenario of a false-data injection attack shows how one can use the Stackelberg game to find the optimal detector tuning.
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| 30. |
- Umsonst, David, et al.
(author)
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On the confidentiality of linear anomaly detector states
- 2019
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In: Proceedings of the American Control Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538679265 ; , s. 397-403
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Conference paper (peer-reviewed)abstract
- A malicious attacker with access to the sensor channel in a feedback control system can severely affect the physical system under control, while simultaneously being hard to detect. A properly designed anomaly detector can restrict the impact of such attacks, however. Anomaly detectors with an internal state (stateful detectors) have gained popularity because they seem to be able to mitigate these attacks more than detectors without a state (stateless detectors). In the analysis of attacks against control systems with anomaly detectors, it has been assumed that the attacker has access to the detector's internal state, or designs its attack such that it is not detected regardless of the detector's state. In this paper, we show how an attacker can realize the first case by breaking the confidentiality of a stateful detector state evolving with linear dynamics, while remaining undetected and imitating the statistics of the detector under nominal conditions. The realization of the attack is posed in a convex optimization framework using the notion of Kullback-Leibler divergence. Further, the attack is designed such that the maximum mean estimation error of the Kalman filter is maximized at each time step by exploiting dual norms. A numerical example is given to illustrate the results.
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| 31. |
- Umsonst, David, et al.
(author)
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On the confidentiality of linear anomaly detector states
- 2019
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In: 2019 American Control Conference (ACC). - 9781538679265 - 9781538679272 - 9781538679289 - 9781538679012 ; , s. 397-403
-
Conference paper (peer-reviewed)abstract
- A malicious attacker with access to the sensor channel in a feedback control system can severely affect the physical system under control, while simultaneously being hard to detect. A properly designed anomaly detector can restrict the impact of such attacks, however. Anomaly detectors with an internal state (stateful detectors) have gained popularity because they seem to be able to mitigate these attacks more than detectors without a state (stateless detectors). In the analysis of attacks against control systems with anomaly detectors, it has been assumed that the attacker has access to the detector's internal state, or designs its attack such that it is not detected regardless of the detector's state. In this paper, we show how an attacker can realize the first case by breaking the confidentiality of a stateful detector state evolving with linear dynamics, while remaining undetected and imitating the statistics of the detector under nominal conditions. The realization of the attack is posed in a convex optimization framework using the notion of Kullback-Leibler divergence. Further, the attack is designed such that the maximum mean estimation error of the Kalman filter is maximized at each time step by exploiting dual norms. A numerical example is given to illustrate the results.
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| 32. |
- Umsonst, David, et al.
(author)
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Security analysis of control system anomaly detectors
- 2017
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In: American Control Conference (ACC), 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509059928 ; , s. 5500-5506
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Conference paper (peer-reviewed)abstract
- Two anomaly detectors for control systems are analyzed with respect to their sensitivity to malicious data injection attacks. A stateless anomaly detector based on the current residual signal is compared to a cumulative sum detector. The worst-case impact of a stealthy time-limited data injection attack is characterized for both detectors by a non-convex optimization problem and compared to determine which detector limits the impact the most. We prove that the problem can be solved by means of a set of convex optimization problems. Simulations verify that finding the right configuration for the cumulative sum is crucial to limit the worst-case attack impact more than with a stateless anomaly detector.
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| 33. |
- Umsonst, David
(author)
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Tuning of Anomaly Detectors in the Presence of Sensor Attacks
- 2019
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Licentiate thesis (other academic/artistic)abstract
- Critical infrastructures, such as the power grid and water distribution networks, are the backbone of our modern society. With the integration of computational devices and communication networks in critical infrastructures, they have become more efficient, but also more vulnerable to cyberattacks. Due to the underlying physical process, these cyberattacks can not only have a financial and ecological impact, but also cost human lives. Several reported cyberattacks on critical infrastructures show that it is vital to protect them from these attacks. Critical infrastructures typically rely on accurate sensor measurements for optimal performance. In this thesis, we, therefore, look into attacks that corrupt the measurements.The first part of the thesis is concerned with the feasibility of a worst-case sensor attack. The attacker's goal is to maximize its impact, while remaining undetected by an anomaly detector. The investigated worst-case attack strategy needs the exact controller state for its execution. Therefore, we start by looking into the feasibility of estimating the controller state by an attacker that has full model knowledge and access to all sensors. We show that an unstable controller prevents the attacker from estimating the controller state exactly and, therefore, makes the attack non-executable. Since unstable controllers come with their own issues, we propose a defense mechanism based on injecting uncertainty into the controller. Next, we examine the confidentiality of the anomaly detector. With access to the anomaly detector state, the attacker can design a more powerful attack. We show that, in the case of a detector with linear dynamics, the attacker is able to obtain an accurate estimate of the detector’s state.The second part of the thesis is concerned with the performance of anomaly detectors under the investigated attack in the first part. We use a previously proposed metric to compare the performance of a χ2, cumulative sum (CUSUM), and multivariate exponentially weighted moving average (MEWMA) detectors. This metric depends on the attack impact and average time between false alarms. For two different processes, we observe that the CUSUM and MEWMA detectors, which both have internal dynamics, can mitigate the attack impact more than the static χ2 detector. Since this metric depends on the attack impact, which is usually hard to determine, we then propose a new metric. The new metric depends on the number of sensors, and the size of an invariant set guaranteeing that the attack remains undetected. The new metric leads to similar results as the previously proposed metric, but is less dependent on the attack modeling. Finally, we formulate a Stackelberg game to tune the anomaly detector thresholds in a cost-optimal manner, where the cost depends on the number of false alarms and the impact an attack would cause.
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| 34. |
- Urbina, David I., et al.
(author)
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Survey and New Directions for Physics-Based Attack Detection in Control Systems
- 2016
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Reports (other academic/artistic)abstract
- Monitoring the “physics” of control systems to detect attacks is a growing area of research. In its basic form a security monitor creates time-series models of sensor readings for an industrial control system and identifies anomalies in these measurements in order to identify potentially false control commands or false sensor readings. In this paper, we review previous work based on a unified taxonomy that allows us to identify limitations, unexplored challenges, and new solutions. In particular, we propose a new adversary model and a way to compare previous work with a new evaluation metric based on the trade-off between false alarms and the negative impact of undetected attacks. We also show the advantages and disadvantages of three experimental scenarios to test the performance of attacks and defenses: real-world network data captured from a large-scale operational facility, a fully-functional testbed that can be used operationally for water treatment, and a simulation of frequency control in the power grid.
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| 35. |
- Xochelli, Aliki, et al.
(author)
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Chronic Lymphocytic Leukemia with Mutated IGHV4-34 Receptors : Shared and Distinct Immunogenetic Features and Clinical Outcomes
- 2017
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In: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 23:17, s. 5292-5301
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Journal article (peer-reviewed)abstract
- Purpose: We sought to investigate whether B cell receptor immunoglobulin (BcR IG) stereotypy is associated with particular clinicobiological features among chronic lymphocytic leukemia (CLL) patients expressing mutated BcR IG (M-CLL) encoded by the IGHV4-34 gene, and also ascertain whether these associations could refine prognostication. Experimental Design: In a series of 19,907 CLL cases with available immunogenetic information, we identified 339 IGHV4-34expressing cases assigned to one of the four largest stereotyped M-CLL subsets, namely subsets #4, #16, #29 and #201, and investigated in detail their clinicobiological characteristics and disease outcomes. Results: We identified shared and subset-specific patterns of somatic hypermutation (SHM) among patients assigned to these subsets. The greatest similarity was observed between subsets #4 and #16, both including IgG-switched cases (IgG-CLL). In contrast, the least similarity was detected between subsets #16 and #201, the latter concerning IgM/D-expressing CLL. Significant differences between subsets also involved disease stage at diagnosis and the presence of specific genomic aberrations. IgG subsets #4 and #16 emerged as particularly indolent with a significantly (P < 0.05) longer time-to-first-treatment (TTFT; median TTFT: not yet reached) compared with the IgM/D subsets #29 and #201 (median TTFT: 11 and 12 years, respectively). Conclusions: Our findings support the notion that BcR IG stereotypy further refines prognostication in CLL, superseding the immunogenetic distinction based solely on SHM load. In addition, the observed distinct genetic aberration landscapes and clinical heterogeneity suggest that not all M-CLL cases are equal, prompting further research into the underlying biological background with the ultimate aim of tailored patient management.
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| 36. |
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