| 1. |
- Abramsson, Mia L, et al.
(författare)
-
Charge engineering reveals the roles of ionizable side chains in electrospray ionization mass spectrometry
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The role of ionizable side chains in the electrospray ionization mass spectrometry of intact proteins remains hotly debated but has not been conclusively addressed because multiple chargeable sites are present in virtually all proteins. Using engineered soluble proteins, we show that ionizable side chains are completely dispensable for charging under native conditions, but if present, they are preferential protonation sites. The absence of ionizable side chains results in identical charge state distributions under native-like and denaturing conditions, whilst co-existing conformers can be distinguished using ion mobility separation. An excess of ionizable side chains, on the other hand, effectively modulates protein ion stability. We conclude that the sum of charges is governed solely by Coulombic terms, while their locations affect the stability of the protein in the gas phase.
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| 2. |
- Abramsson, Mia L., et al.
(författare)
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Charge Engineering Reveals the Roles of Ionizable Side Chains in Electrospray Ionization Mass Spectrometry
- 2021
-
Ingår i: JACS Au. - : American Chemical Society (ACS). - 2691-3704. ; 1:12, s. 2385-2393
-
Tidskriftsartikel (refereegranskat)abstract
- In solution, the charge of a protein is intricately linked to its stability, but electrospray ionization distorts this connection, potentially limiting the ability of native mass spectrometry to inform about protein structure and dynamics. How the behavior of intact proteins in the gas phase depends on the presence and distribution of ionizable surface residues has been difficult to answer because multiple chargeable sites are present in virtually all proteins. Turning to protein engineering, we show that ionizable side chains are completely dispensable for charging under native conditions, but if present, they are preferential protonation sites. The absence of ionizable side chains results in identical charge state distributions under native-like and denaturing conditions, while coexisting conformers can be distinguished using ion mobility separation. An excess of ionizable side chains, on the other hand, effectively modulates protein ion stability. In fact, moving a single ionizable group can dramatically alter the gas-phase conformation of a protein ion. We conclude that although the sum of the charges is governed solely by Coulombic terms, their locations affect the stability of the protein in the gas phase.
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| 3. |
- Borg, Tessie, et al.
(författare)
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Diastereoselective Nucleophilic Addition to Aldehydes with Polar alpha- and alpha,beta-Substituents
- 2011
-
Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 353:11-12, s. 2022-2036
-
Tidskriftsartikel (refereegranskat)abstract
- The stereoselectivities obtained in Lewis acid-promoted Mukaiyama aldol additions and Sakurai allylations of mono-, and syn- and anti-disubstituted aldehydes possessing various polar alpha- and beta-substituents under non-chelating conditions are presented. The stereochemical outcome in the nucleophilic addition to alpha-substituted aldehydes containing an alpha-benzyloxy, alpha-fluoro or alpha-sulfonamide substituent are accurately predicted by current stereoinduction models. In contrast, the selectivitites obtained from addition of sterically demanding nucleophiles to alpha-chloro-substituted aldehydes cannot be rationalized by the same models and an alternative is discussed. The stereochemichal outcome in the additions to alpha, beta-disubstituted aldehydes is more complex and cannot be predicted using current models.
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| 4. |
- Borg, Tessie, et al.
(författare)
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Mukaiyama aldol addition to α-chloro-substituted aldehydes. Origin of the unexpected syn selectivity.
- 2010
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 46:8, s. 1281-1283
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Tidskriftsartikel (refereegranskat)abstract
- The addition of sterically demanding enolsilanes to alpha-chloro aldehydes results unexpectedly in preferential formation of the anti-PFA product (1,2-syn), while the addition of the corresponding boron enolate furnishes the expected polar Felkin-Anh product (1,2-anti). A stereoinduction model explaining these observations is proposed.
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| 5. |
- Danielsson, Jakob, et al.
(författare)
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1,3-Dipolar Cycloaddition of Azomethine Ylides to Aldehydes : Synthesis of anti alpha-Amino-beta-Hydroxy Esters
- 2011
-
Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :3, s. 607-613
-
Tidskriftsartikel (refereegranskat)abstract
- A 1,3-dipolar cycloaddition reaction of azomethine ylides to aldehydes is described. The azomethine ylides, generated by thermal electrocyclic ring opening of aziridines, adds to aldehydes in good yields with moderate to good selectivities to furnish oxazolidines. The oxazolidines were subsequently hydrolyzed to the corresponding amino alcohols, giving the anti diastereomer as the major product.
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| 6. |
- Danielsson, Jakob, et al.
(författare)
-
A systematic mapping study on real-Time cloud services
- 2018
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Ingår i: Proceedings - 11th IEEE/ACM International Conference on Utility and Cloud Computing Companion, UCC Companion 2018. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728103594 ; , s. 245-251
-
Konferensbidrag (refereegranskat)abstract
- Cloud computing is relatively a new technique to host and use the services and applications from the internet. Although it offers a multitude of advantages like scalability, low operating cost, accessibility and maintainability, etc., they are often not utilized to the fullest due to the lack of timeliness property associated with the cloud. Cloud services are mainly designed to maximize throughput and utilization of resources and hence incorporating predictable execution time properties in to the cloud is arduous. Nevertheless, cloud still remains a highly attractive platform for hosting real-Time applications and services owing to features like elasticity, multi-Tenancy, ability to survive hardware failures, virtualization support and abstraction layer support which provides flexibility and portability. In order for real-Time safety-critical applications to exploit the potential of cloud computing, it is essential to ensure the predictable real-Time behavior of cloud services. In this paper, we perform a systematic mapping study on real-Time cloud services to identify the current research directions and potential research gaps. Our study focuses on analyzing the current architectures and software techniques that are available at present to incorporate real-Time property of the cloud services. We also aim at investigating the current challenges involved in realizing a predictable real-Time behavior of cloud services.
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| 7. |
- Danielsson, Jakob
(författare)
-
Automatic Characterization and Mitigation of Shared-resource Contention in Multi-core Systems
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multi-core computers are infamous for being hard to use in time-critical systems due to execution-time variations as an effect of shared resource contention. In this thesis, we study the problem of shared resource contention, which occurs when multiple applications executing on different cores do not have exclusive access to of a shared hardware resource. We investigate performance variations of parallel tasks in multi-core systems and present a method to pinpoint the source of the resource contention using hardware performance counters. We investigate mitigation methods for performance variations due to resource contention, including the Jailhouse hypervisor and the cache-partitioning tool PALLOC. We propose a benchmark strategy that quantifies the isolation gained from a specific isolation technique and exemplify this strategy using the Jailhouse hypervisor. We furthermore present and implement solutions for cache-partition allocation during application runtime. Our implementation aims to avoid over-provisioning of cache through pre-runtime estimations of an application's dependency towards the cache and continuous re-partitioning of the cache memory during application runtime.The primary goal of this thesis is to contribute to a process that automates some of the tedious manual testing needed to detect resource contention bottlenecks. The methods we present in this provide a holistic solution for automatic mitigating resource-contention in a multi-core system. First, we evaluate the risk for shared resource contention when several applications execute simultaneously. We then allocate partitions to mitigate resource contention for applications that risk severe performance degradations. We finally present methods that dynamically re-allocate partition space to meet the performance requirements of the running applications.
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| 8. |
- Danielsson, Jakob, et al.
(författare)
-
Automatic Quality of Service Control in Multi-core Systems using Cache Partitioning
- 2021
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we present a last-level cache partitioning controller for multi-core systems. Our objective is to control the Quality of Service (QoS) of applications in multi-core systems by monitoring run-time performance and continuously re-sizing cache partition sizes according to the applications' needs. We discuss two different use-cases; one that promotes application fairness and another one that prioritizes applications according to the system engineers' desired execution behavior. We display the performance drawbacks of maintaining a fair schedule for all system tasks and its performance implications for system applications. We, therefore, implement a second control algorithm that enforces cache partition assignments according to user-defined priorities rather than system fairness. Our experiments reveal that it is possible, with non-instrusive (0.3-0.7\% CPU utilization) cache controlling measures, to increase performance according to setpoints and maintain the QoS for specific applications in an over-saturated system.
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| 9. |
- Danielsson, Jakob
(författare)
-
Characterization of Shared Resource Contention in Multi-core Systems
- 2019
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multi-core computers are infamous for being hard to use in time-critical systems due to execution-time variations as an effect of shared resource contention. In this thesis we study the problem of shared resource contention which occurs when multiple applications executing on different cores do not have exclusive ownership of a shared resource. We investigate performance variations of parallel tasks in multi-core systems and present a method to pinpoint the source of the resource contention using existing hardware performance counters. Furthermore, we investigate methods to mitigate performance variations using resource isolation techniques. We present a methodology for verifying isolation and tested the achieved isolation using the Jailhouse hypervisor. We further investigate shared cache memory isolation techniques using a page coloring tool called PALLOC. Page-coloring is used for partitioning the cache, assigning specific cache lines to specific processes. Page coloring can however cause system performance degradation since it decreases the total amount of cache memory available for each process. Finally, we propose a dynamic partitioning assignment policy which assigns cache partitions to a process according to an adaptive model based on the process performance. The general conclusion from our investigations is that a large body of applications can suffer from shared resource contention and that techniques for mitigating resource contention are in dire need. Our methods measure and characterise applications, identifies resource contention and finally study isolation techniques.
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| 10. |
- Danielsson, Jakob, et al.
(författare)
-
Investigating execution-characteristics of feature-detection algorithms
- 2017
-
Ingår i: IEEE Conference on Emerging Technologies and Factory Automation. - : Institute of Electrical and Electronics Engineers Inc.. - 1946-0740 .- 1946-0759. ; Part F134116, s. 1-4
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss how to obtain information of execution characteristics, such as parallelizability and memory utilization, with the final aim to improve the performance and predictability of feature and corner detection algorithms for use in e.g. robotics and autonomous machines. Our aim is to obtain a better understanding of how computer vision algorithms use hardware resources and how to improve the time predictability and execution time of such algorithms when executing on multi-core CPUs. We evaluate a fork-join model applicable to feature detection algorithms and present a method for measuring how well the algorithm performance correlates with hardware resource usage. We have applied our method to the Featured from Accelerated Segment Test (FAST) algorithm. Our characterization of FAST reveals that it is an algorithm with excellent parallelism opportunities, resulting in an almost linear speed-up per core. Our measurements also reveal that the performance of FAST correlates very little with the number number of misses in the L1 data cache, L1 instruction cache, data translation lookaside buffer and L2 cache. Thus, the FAST algorithm will not have a negative effect on the execution time when the input data fits in the L2 cache.
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| 11. |
- Danielsson, Jakob, et al.
(författare)
-
LLM-shark -- A Tool for Automatic Resource-boundness Analysis and Cache Partitioning Setup
- 2021
-
Ingår i: 45th IEEE Annual Computers, Software, and Applications Conference, COMPSAC 2021. - 9781665424639 ; , s. 49-58
-
Konferensbidrag (refereegranskat)abstract
- We present LLM-shark, a tool for automatic hardware resource-boundness detection and cache-partitioning. Our tool has three primary objectives: First, it determines the hardware resource-boundness of a given application. Secondly, it estimates the initial cache partition size to ensure that the application performance is conserved and not affected by other processes competing for cache utilization. Thirdly, it continuously monitors that the application performance is maintained over time and, if necessary, change the cache partition size. We demonstrate LLM-shark's functionality through a series of tests using six different applications, including a set of feature detection algorithms and two synthetic applications. Our tests reveal that it is possible to determine an application's resource-boundness using a Pearson-correlation scheme implemented in LLM-shark. We propose a scheme to size cache partitions based on the correlation coefficient applications depending on their resource boundness.
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| 12. |
- Danielsson, Jakob, et al.
(författare)
-
Measurement-based evaluation of data-parallelism for OpenCV feature-detection algorithms
- 2018
-
Ingår i: Staying Smarter in a Smartening World COMPSAC'18. - 9781538626665 ; , s. 701-710
-
Konferensbidrag (refereegranskat)abstract
- We investigate the effects on the execution time, shared cache usage and speed-up gains when using data-partitioned parallelism for the feature detection algorithms available in the OpenCV library. We use a data set of three different images which are scaled to six different sizes to exercise the different cache memories of our test architectures. Our measurements reveal that the algorithms using the default settings of OpenCV behave very differently when using data-partitioned parallelism. Our investigation shows that the executions of the algorithms SURF, Dense and MSER correlate to L3-cache usage and they are therefore not suitable for data-partitioned parallelism on multi-core CPUs. Other algorithms: BRISK, FAST, ORB, HARRIS, GFTT, SimpleBlob and SIFT, do not correlate to L3-cache in the same extent, and they are therefore more suitable for data-partitioned parallelism. Furthermore, the SIFT algorithm provides the most stable speed-up, resulting in an execution between 3 and 3.5 times faster than the original execution time for all image sizes. We also have evaluated the hardware resource usage by measuring the algorithm execution time simultaneously with the L3-cache usage. We have used our measurements to conclude which algorithms are suitable for parallelization on hardware with shared resources.
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| 13. |
- Danielsson, Jakob, et al.
(författare)
-
Modelling Application Cache Behavior using Regression Models
- 2021
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we describe the creation of resource usage forecasts for applications with unknown execution characteristics, by evaluating different regression processes, including autoregressive, multivariate adaptive regression splines, exponential smoothing, etc. We utilize Performance Monitor Units (PMU) and generate hardware resource usage models for the L-2-cache and the L-3-cache using nine different regression processes. The measurement strategy and regression process methodology are general and applicable to any given hardware resource when performance counters are available. We use three benchmark applications: the SIFT feature detection algorithm, a standard matrix multiplication, and a version of Bubblesort. Our evaluation shows that Multi Adaptive Regressive Spline (MARS) models generate the best resource usage forecasts among the considered models, followed by Single Exponential Splines (SES) and Triple Exponential Splines (TES).
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| 14. |
- Danielsson, Jakob
(författare)
-
Natural Product Synthesis and Development of Novel Reaction Methodology
- 2014
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the development of new reaction methodology for stereoselective synthesis, as well as total synthesis of natural products and investigations of the stereochemical outcome in the Mukaiyama aldol reaction. Chapter 2 describes efforts made towards the total synthesis of the oxindole natural products perophoramidine and the communesin. The first part of this chapter aims to develop a domino carbopalladation-carbonylation reaction using tetrasubstituted olefins for the installation of the vicinal quaternary stereocenters of the target compounds. This approach was ultimately unsuccessful using tetrasubstituted olefins. The second part of this chapter instead relies on a Diels-Alder reaction for the installation of the quaternary stereocenters, and also describes the attempts made to reach the target compound from the Diels-Alder adduct. Chapter 3 concerns the investigation of 1,2- and merged 1,2- and 1,3-asymmetric induction in Mukaiyama aldol additions to α-heteroatom and α,β-heteroatom substituted aldehydes, respectively. In particular, the unexpected 1,2-syn selectivity obtained in the addition of sterically hindered nucleophiles to α-chloro aldehydes is studied, and an explanation for the observed stereochemical trends is proposed. Chapter 4 describes the development of a novel entry to anti-α-amino-β-hydroxy esters by 1,3-dipolar cycloadditions of aldehydes and azomethine ylides, generated by thermolysis of aziridines.
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| 15. |
- Danielsson, Jakob, et al.
(författare)
-
Performance Evaluation of Network Convergence Time Measurement Techniques
- 2017
-
Ingår i: International Conference on Emerging Technologies And Factory Automation ETFA'17. - 9781509065059 ; , s. 1-7
-
Konferensbidrag (refereegranskat)abstract
- In this paper we evaluate solutions that provide measurements for the network convergence time in switched Ethernet networks when links failures happen. We evaluate three solutions to measure the network convergence time in a faulty situation. Compared to the commercially available solutions, our proposals are cost-effective, portable, and open source. Thus, they are easy to deploy on many testbeds. We show the performance of the solutions by measuring different metrics including jitter, network convergence time and packet loss during the network recovery time. Our measurements indicate that it is possible to accurately measure the network convergence time using a packet sender which does not suffer interference from the overlying operating system. Furthermore, we noticed that the packet sniffer TShark did not suffer from kernel interrupts from overlying operating systems.
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| 16. |
- Danielsson, Jakob, et al.
(författare)
-
Resource Depedency Analysis in Multi-Core Systems
- 2020
-
Ingår i: Proceedings - 2020 IEEE 44th Annual Computers, Software, and Applications Conference, COMPSAC 2020. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728173030 ; , s. 87-94
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we evaluate different methods for statistical determination of application resource dependency in multi-core systems. We measure the performance counters of an application during run-time and create a system resource usage profile. We then use the resource profile to evaluate the application dependency on the specific resource. We discuss and evaluate two methods to process the data, including moving average filter and partitioning the data into smaller segments in order to interpret data for correlation calculations. Our aim with this study is to evaluate and create a generalizeable methods for automatic determination of resource dependencies. The final outcome of the methods used in this study is the answer to the question: 'To what resources is this application dependent on?'. The recommendation of this tool will be used in conjunction with our last-level cache partitioning controller (LLC-PC), to make decision if an application should receive last-level cache partition slices.
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| 17. |
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| 18. |
- Danielsson, Jakob, 1985-
(författare)
-
Stereoselective Nucleophilic Additions to Aldehydes and Synthesis of α-Amino-β- Hydroxy-Esters
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the development of new reaction methodology as well as stereochemical investigations. The first part concerns the investigation of 1,2- and merged 1,2- and 1,3- asymmetric induction in Mukaiyama aldol additions to α-heteroatom and α,β- heteroatom substituted aldehydes respectively. In particular, the unexpected 1,2-syn selectivity obtained in the addition of sterically hindered nucleophiles to α-chloroaldehydes is examined, and an explanation for the observed stereochemical trends is proposed. The second part describes the development of a novel entry to α-amino-β- hydroxy esters by a 1,3-dipolar cycloaddition reaction of aldehydes and azomethine ylides, generated by thermolysis of aziridines. The third part deals with our efforts to develop a novel entry to vicinal all- carbon quaternary centers, based on an intramolecular domino Heck- carbonylation reaction using tetrasubstituted olefins.
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| 19. |
- Danielsson, Jakob, et al.
(författare)
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Studies Toward Communesin F: A Diels-Alder Approach.
- 2014
-
Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7052 .- 1523-7060. ; 16:3, s. 784-787
-
Tidskriftsartikel (refereegranskat)abstract
- A Diels-Alder reaction is used as a key step in a synthetic study toward communesin F, in order to simultaneously introduce both of the all-carbon quaternary stereocenters with complete control of relative stereochemistry. Further manipulations of the cycloadduct, toward the hexacyclic core-structure of communesin F, are also disclosed.
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| 20. |
- Danielsson, Jakob, et al.
(författare)
-
Testing Performance-Isolation in Multi-Core Systems
- 2019
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present a methodology to be used for quantifying the level of performance isolation for a multi-core system. We have devised a test that can be applied to breaches of isolation in different computing resources that may be shared between different cores. We use this test to determine the level of isolation gained by using the Jailhouse hypervisor compared to a regular Linux system in terms of CPU isolation, cache isolation and memory bus isolation. Our measurements show that the Jailhouse hypervisor provides performance isolation of local computing resources such as CPU. We have also evaluated if any isolation could be gained for shared computing resources such as the system wide cache and the memory bus controller. Our tests show no measurable difference in partitioning between a regular Linux system and a Jailhouse partitioned system for shared resources. Using the Jailhouse hypervisor provides only a small noticeable overhead when executing multiple shared-resource intensive tasks on multiple cores, which implies that running Jailhouse in a memory saturated system will not be harmful. However, contention still exist in the memory bus and in the system-wide cache.
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| 21. |
- Danielsson, Jakob, et al.
(författare)
-
Total Synthesis of Dehaloperophoramidine : Evolution of a Synthesis
- 2017
-
Ingår i: Strategies and Tactics in Organic Synthesis. - 1874-6004. ; 13, s. 217-242
-
Bokkapitel (refereegranskat)abstract
- This account describes our efforts toward developing a stereodivergent entry to perophoramidine and the communesin alkaloids. The original approach toward our simplified model substrates relied on a palladium-catalyzed carbopalladation–carbonylation of a tetrasubstituted olefin to install the vicinal all-carbon quaternary stereocenters present in the target molecules, the olefin's stereochemistry thus dictating the relative stereochemistry of the quaternary stereocenters. Although the carbonylation–carbopalladation sequence worked well for trisubstituted olefins, only premature esterification was observed when using tetrasubstituted alkene substrates. Our second approach made use of the latent symmetry embedded in our target molecules. A Diels–Alder reaction or SmI2-mediated bis-alkylation of isoindigo was to be used to access the communesin and perophoramidine scaffolds, respectively. We found that due to unfavorable thermodynamics, it was not possible to reach the communesin scaffold. However, two new complexity-generating, cascade reactions were encountered en route to the synthesis of dehaloperophoramidine, resulting in a short and efficient synthesis.
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| 22. |
- Danielsson, Torkel, et al.
(författare)
-
A climbing robot for autonomous inspection of live power lines
- 2006
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Ingår i: Proceedings of ASER2006 3rd International Workshop on Advances in Service Robots.
-
Konferensbidrag (refereegranskat)abstract
- Power line inspection is risky and repetitive, thus replacement by a service robot is desirable. A robot for this task, the line inspection robot (LIR), is described. Previous work has been done and our contribution is to decrease complexity in the mechanics of the robot and to structure the control of the robot through reinforcement learning. Two issues need to be addressed in the creation of the LIR. Firstly, the robot needs to traverse a power line mounted on a conductor and pass obstacles on it. Secondly, the LIR needs to detect faults on the power line without help of human operators.
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| 23. |
- Haglund, Mattias, et al.
(författare)
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A methodological study of locus coeruleus degeneration in dementing disorders
- 2016
-
Ingår i: Clinical Neuropathology. - 0722-5091. ; 35:5, s. 287-294
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Degeneration of the locus coeruleus (LC) of the brain stem is a recognized phenomenon in Alzheimer's disease (AD), in dementia with Lewy bodies (DLB), and in Parkinson's disease with dementia (PDD). Prior studies have suggested that LC degeneration can be used to differentiate various dementing disorders histologically, but the paucity of methodological data may hamper systematic research on this nucleus. Purpose: The purpose of this study was to evaluate various approaches to quantifying LC degeneration in dementing disorders, and to inform future decisions regarding the most appropriate method for diagnostics and research. Methods: 105 LCs from brains of demented individuals with AD, DLB/PDD, vascular dementia (VaD), mixed dementia (AD+VaD), or frontotemporal lobar degeneration (FTLD) were examined, and the extent of LC degeneration was assessed using macroscopic evaluation, cell counting, and two degeneration scales. Scores were compared across diagnostic categories; diagnostic utility and intra- and interobserver reliability were assessed. Results: AD and DLB/PDD were associated with greater LC damage using either assessment method, significantly different from VaD and FTLD. Macroscopic appearance was informative, but cell counting was more sensitive and specific. The degeneration scales did not add significant diagnostic value over cell counting and were associated with greater observer variability. Conclusions: The LC degenerates in certain dementia subtypes, especially in AD and DLB/PDD. Macroscopic assessment of the LC postmortem can be used to differentiate between disorders associated with degeneration (AD, DLB/PDD) or sparing (VaD) of the LC, but counting LC cells in a representative pontine section is the most appropriate method by which to assess LC degeneration.
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| 24. |
- Hart, Andrew R, et al.
(författare)
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Diet in the aetiology of ulcerative colitis: A European prospective cohort study
- 2008
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Ingår i: Digestion. - : S. Karger AG. - 1421-9867 .- 0012-2823. ; 77:1, s. 57-64
-
Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: The causes of ulcerative colitis are unknown, although it is plausible that dietary factors are involved. Case-control studies of diet and ulcerative colitis are subject to recall biases. The aim of this study was to examine the prospective relationship between the intake of nutrients and the development of ulcerative colitis in a cohort study. Methods: The study population was 260,686 men and women aged 20-80 years, participating in a large European prospective cohort study (EPIC). Participants were residents in the UK, Sweden, Denmark, Germany or Italy. Information on diet was supplied and the subjects were followed up for the development of ulcerative colitis. Each incident case was matched with four controls and dietary variables were divided into quartiles. Results: A total of 139 subjects with incident ulcerative colitis were identified. No dietary associations were detected, apart from a marginally significant positive association with an increasing percentage intake of energy from total polyunsaturated fatty acids (trend across quartiles OR = 1.19 (95% CI = 0.99-1.43) p = 0.07). Conclusions: No associations between ulcerative colitis and diet were detected, apart from a possible increased risk with a higher total polyunsaturated fatty acid intake. A biological mechanism exists in that polyunsaturated fatty acids are metabolised to pro-inflammatory mediators.
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| 25. |
- Imtiaz, Shamoona, et al.
(författare)
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Automatic Platform-Independent Monitoring and Ranking of Hardware Resource Utilization
- 2021
-
Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728129891
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we discuss a method for automatic monitoring of hardware and software events using performance monitoring counters. Computer applications are complex and utilize a broad spectra of the available hardware resources, where multiple performance counters can be of significant interest to understand. The number of performance counters that can be captured simultaneously is, however, small due to hardware limitations in most modern computers. We suggest a platform independent solution to automatically retrieve hardware events from an underlying architecture. Moreover, to mitigate the hardware limitations we propose a mechanism that pinpoints the most relevant performance counters for an application's performance. In our proposal, we utilize the Pearson's correlation coefficient to rank the most relevant performance counters and filter out those that are most relevant and ignore the rest.
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| 26. |
- Linder, Tova, et al.
(författare)
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On Using Crowd-sourced Network Measurements for Performance Prediction
- 2016
-
Ingår i: <em>Proc. IEEE/IFIP Wireless On-demand Network Systems and Services Conference (IEEE/IFIP WONS)</em>, Cortina d'Ampezzo, Italy, Jan. 2016.. - : IEEE Computer Society Digital Library. - 9783901882791 ; , s. 1-8
-
Konferensbidrag (refereegranskat)abstract
- Geo-location-based bandwidth prediction together with careful download scheduling for mobile clients can be used to minimize download times, reduce energy usage, and improve streaming performance. Although crowd-sourced measurements provide an important prediction tool, little is known about the prediction accuracy and improvements such datasets can provide. In this paper we use a large-scale crowd-sourced dataset from Bredbandskollen, Sweden's primary speedtest service, to evaluate the prediction accuracy and achievable performance improvements with such data. We first present a scalable performance map methodology that allows fast insertion/retrieval of geo-sparse measurements, and use this methodology to characterize the Bredbandskollen usage. Second, we analyze the bandwidth variations and predictability of the download speeds observed within and across different locations, when accounting for various factors. Third, we evaluate the relative performance improvements achievable by users leveraging different subsets of measurements (capturing effects of limited sharing or filtering based on operator, network technology, or both) when predicting opportune locations to perform downloads. Our results are encouraging for both centralized and peer-to-peer performance map solutions. For example, most measurements are done in locations with many measurements and good prediction accuracy, and further improvements are possible through filtering (e.g., based on operator and technology) or limited information sharing.
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| 27. |
- Roger, Fabian, et al.
(författare)
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Airborne environmental DNA metabarcoding for the monitoring of terrestrial insects—A proof of concept from the field
- 2022
-
Ingår i: Environmental DNA. - : Wiley. - 2637-4943. ; 4:4, s. 790-807
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Tidskriftsartikel (refereegranskat)abstract
- Biodiversity is in decline due to human-induced pressures on ecosystems around the world. To be able to counteract this alarming trend, it is paramount to closely monitor biodiversity at global scales. Because this is practically impossible with traditional methods, the last decade has seen a strong push for new solutions. In aquatic ecosystems, the monitoring of species from environmental DNA (eDNA) has emerged as one of the most powerful tools at our disposal, but in terrestrial ecosystems, the power of eDNA for monitoring has so far been hampered by the local scale of the samples. In this study, we report the successful detection of insects from airborne eDNA from samples taken in the field. We compare our results to two traditional insect monitoring methods (1) light traps for moth monitoring and (2) transect walks for the monitoring of butterflies and wild bees. Airborne eDNA metabarcoding revealed DNA from six classes of arthropods, and twelve order of insects—including representatives from the four largest orders: Diptera (flies), Lepidoptera (butterflies and moths), Coleoptera (beetles), and Hymenoptera (bees, wasps, and ants). We did not detect all species observed using traditional methods and suggest further directions for the development of airborne eDNA metabarcoding. We also recovered DNA from nine species of vertebrates, including frogs, birds, and mammals as well as from 12 other phyla. Airborne eDNA has the potential to become a powerful tool for terrestrial biodiversity monitoring, with many impactful applications including the monitoring of pests, invasive, or endangered species and disease vectors.
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| 28. |
- Seashore-Ludlow, Brinton, et al.
(författare)
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Domino Carbopalladation-Carbonylation : Investigation of Substrate Scope
- 2012
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 354:1, s. 205-216
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Tidskriftsartikel (refereegranskat)abstract
- This work gives an in depth account of our domino carbopalladation-carbonylation method for substrates possessing beta-hydrogens. The scope of the method is examined for allylic amines containing trisubstituted olefins and we detail our attempts toward the diastereospecific synthesis of contiguous quaternary centers using this technology. The results give key insights into the relative rates of the competing reactions of the alkyl palladium intermediates, which is crucial for the understanding and development of new domino processes.
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| 29. |
- Vitucci, Carlo, et al.
(författare)
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A Reliability-oriented Faults Taxonomy and a Recovery-oriented Methodological Approach for Systems Resilience
- 2022
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Ingår i: Proceedings - 2022 IEEE 46th Annual Computers, Software, and Applications Conference, COMPSAC 2022. - : IEEE. - 9781665488105 ; , s. 48-55
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Konferensbidrag (refereegranskat)abstract
- Fault management is an important function that impacts the design of any digital system, from the simple kiosk in a shop to a complex 6G network. It is common to classify fault conditions into different taxonomies using terms like fault or error. Fault taxonomies are often suitable for managing fault detection, fault reporting, and fault localization but often neglect to support all different functions required by a fault management process. A correctly implemented fault management process must be able to distinguish between defects and faults, decide upon ap-propriate actions to recover the system to an ideal state, and avoid an error condition. Fault management is a multi-disciplinary process where recovery actions are deployed promptly by com-bined hardware, firmware, and software orchestration. The importance of fault management processes significantly increases with modern nanometer technologies, which suffer the risk of so-called soft errors, a corruption of a bit cells that can happen due to spurious disturbance, like cosmic radiation. Modern fault management implementations must support recovery actions for soft errors to ensure a steady system. This paper describes an extended fault classification model that emphasizes fault management and recovery actions. We aim to show how the reliability-based fault taxonomy definition is more suitable for the overall fault management process.
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| 30. |
- Vitucci, Carlo, 1967-, et al.
(författare)
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Run Time Memory Error Recovery Process in Networking System.
- 2023
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Ingår i: 7th IEEE International Conference on System Reliability and Safety. - Bologna, Italy : IEEE conference proceedings. - 9798350306064 ; , s. 590-597
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Konferensbidrag (refereegranskat)abstract
- System memory errors have always been problematic; today, they cause more than forty percent of confirmed hardware errors in repair centers for both data centers and telecommunications network nodes. Therefore, it is somewhat expected that, in recent years, device manufacturers improved the hardware features to support hardware-assisted fault management implementation. For example, the new standard, DDR5, includes both data redundancy, the so-called Error Correcting Code (ECC), and physical redundancy, the post-package repair (PPR), as mandatory features. Production and repair centers mainly use physical redundancy to replace faulty memory rows. In contrast, field use still needs to be improved, mainly due to a need for integrated system solutions for network nodes. This paper aims to compensate for this shortcoming and presents a system solution for handling memory errors. It is a multi-technology proposition (mixed use of ECC and PPR) based on multi-layer (hardware, firmware, and software) error information exchange.
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