| 1. |
- Kaipainen, Aku L, et al.
(författare)
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Cerebrospinal fluid dynamics in idiopathic intracranial hypertension : a literature review and validation of contemporary findings
- 2021
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Ingår i: Acta Neurochirurgica. - : Springer. - 0001-6268 .- 0942-0940. ; 163:12, s. 3353-3368
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic intracranial hypertension (IIH) is a rare disease of unknown aetiology related possibly to disturbed cerebrospinal fluid (CSF) dynamics and characterised by elevated intracranial pressure (ICP) causing optic nerve atrophy if not timely treated. We studied CSF dynamics of the IIH patients based on the available literature and our well-defined cohort.Method: A literature review was performed from PubMed between 1980 and 2020 in compliance with the PRISMA guideline. Our study includes 59 patients with clinical, demographical, neuro-ophthalmological, radiological, outcome data, and lumbar CSF pressure measurements for suspicion of IIH; 39 patients had verified IIH while 20 patients did not according to Friedman’s criteria, hence referred to as symptomatic controls.Results: The literature review yielded 19 suitable studies; 452 IIH patients and 264 controls had undergone intraventricular or lumbar CSF pressure measurements. In our study, the mean CSF pressure, pulse amplitudes, power of respiratory waves (RESP), and the pressure constant (P0) were higher in IIH than symptomatic controls (p < 0.01). The mean CSF pressure was higher in IIH patients with psychiatric comorbidity than without (p < 0.05). In IIH patients without acetazolamide treatment, the RAP index and power of slow waves were also higher (p < 0.05). IIH patients with excess CSF around the optic nerves had lower relative pulse pressure coefficient (RPPC) and RESP than those without (p < 0.05).Conclusions: Our literature review revealed increased CSF pressure, resistance to CSF outflow and sagittal sinus pressure (SSP) as key findings in IIH. Our study confirmed significantly higher lumbar CSF pressure and increased CSF pressure waves and RAP index in IIH when excluding patients with acetazolamide treatment. In overall, the findings reflect decreased craniospinal compliance and potentially depleted cerebral autoregulation resulting from the increased CSF pressure in IIH. The increased slow waves in patients without acetazolamide may indicate issues in autoregulation, while increased P0 could reflect the increased SSP.
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| 2. |
- Kuisma, Mikael Juhani, 1984, et al.
(författare)
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Localized surface plasmon resonance in silver nanoparticles: Atomistic first-principles time-dependent density-functional theory calculations
- 2015
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 91:11
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Tidskriftsartikel (refereegranskat)abstract
- We observe using ab initio methods that localized surface plasmon resonances in icosahedral silver nanoparticles enter the asymptotic region already between diameters of 1 and 2 nm, converging close to the classical quasistatic limit around 3.4 eV. We base the observation on time-dependent density-functional theory simulations of the icosahedral silver clusters Ag-55 (1.06 nm), Ag-147 (1.60 nm), Ag-309 (2.14 nm), and Ag-561 (2.68 nm). The simulation method combines the adiabatic GLLB-SC exchange-correlation functional with real time propagation in an atomic orbital basis set using the projector-augmented wave method. The method has been implemented for the electron structure code GPAW within the scope of this work. We obtain good agreement with experimental data and modeled results, including photoemission and plasmon resonance. Moreover, we can extrapolate the ab initio results to the classical quasistatically modeled icosahedral clusters.
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| 3. |
- Rantala, P., et al.
(författare)
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Novel Agent-Based Management for Fault-Tolerance in Network-on-Chip
- 2007
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Ingår i: DSD 2007. ; , s. 551-555
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Konferensbidrag (refereegranskat)abstract
- We introduce a novel agent-based reconfiguring concept for futures Network-on-Chip (NoC) systems. The necessary properties to increase architecture level fault tolerance are introduced. The system control is modeled as multi-level agent hierarchy that is able to increase application fault-tolerance and performance with autonomous reactions of agents. Die agent technology adds a system level intelligence level to the traditional NoC system design. The architecture and functions of this system are described on conceptual level. Communication and reconfigufing data flows are presented as study cases. Principles of reconfiguration of a NoC on faulty environment are demonstrated and simulated. Probability of reconfiguration success is measured with different latency requirements and amount of redundancy by Monte Carlo simulations. The effect of network topology in reconfiguration of a faulty mesh was also under research in the simulations.
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| 4. |
- Wei Yin, A., et al.
(författare)
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Hierarchical agent monitoring nocs : A design methodology with scalability and variability
- 2008
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Ingår i: 26th Norchip Conference, Norchip. - 9781424424931 ; , s. 202-207
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Konferensbidrag (refereegranskat)abstract
- Adopting the bio-inspired system architecture, a hierarchical agent monitoring NoC design method is proposed. Based on circuit conditions traced at the run-time, system settings including resource utilization and power supplies are configured hierarchically and adaptively at each architecture level by corresponding agents. This methodology provides systematic design approaches to VLSI circuits under the influence of unpredictable variations and stringent power constraints. Each level of agents autonomously monitor their local components while being supervised by their higher level counterparts. In this manner, the overall performance and efficiency can be maximized for systems of any scale. The feasibility and innovation of this methodology are explained elaborately with low-power optimization and fault-tolerance services, and architectural alternative analysis on the regular NoC platform is presented. An FFT study case demonstrates the functional effectiveness and flexibility of agent-monitored adaptive system configuration in case of component failures.
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| 5. |
- Yin, A. W., et al.
(författare)
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Hierarchical Agent Architecture for Scalable NoC Design with Online Monitoring Services
- 2008
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Ingår i: Proceedings of MICRO 41.
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Konferensbidrag (refereegranskat)abstract
- Hierarchical Agent Architecture is proposed to provideonline monitoring services to NoC-based systems. Basedon circuit conditions traced at the run-time, system settingsare monitored adaptively by agents at each architectural level.This monitoring approach partitions various online diagnosticand management services onto hierarchical implementation levelsso as to provide scalability and variability for large-scale NoCdesign. This paper explains the monitoring interaction betweenagent levels, and focuses on system optimization alternativeshandled by different agent levels. It further quantitatively analyzesthe feasibility and design alternatives in monitoring communicationinterconnection upon regular tile-based NoC layout.Though still under intensive research, the proposed architectureis endowed with promising potential for highly-integrated NoCdesign.
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| 6. |
- Yin, A. W., et al.
(författare)
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Hierarchical Agent Based NoC with DVFS Techniques
- 2011
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Ingår i: International Journal of Design, Analysis and Tools for Integrated Circuits and Systems. - 2223-523X .- 2071-2987. ; 1:1, s. 32-40
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Tidskriftsartikel (refereegranskat)abstract
- Network-on-Chip (NoC) is a promising architecturein the many-core on-chip systems. A hierarchical agentbased NoC architecture is proposed which enables the NoCto autonomously adjust itself, and provide maximum powerefficiency, fault/variation tolerance and system flexibility. Agentsare software or hardware components which monitor and controlthe system at different granularity. Via the joint efforts andinteractions of agents at all levels of the architecture, systemoptimization can be achieved at the runtime. Agent hierarchy,mapping of agents on regular NoC platforms and the functionpartition among the agents are elaborately discussed.Runtime power management with various Dynamic Voltageand Frequency Scaling (DVFS) techniques is analyzed on thehierarchical agent based NoC platform. Conventional powermonitoring techniques can be flexibly incorporated into the functionsof specific levels of agents. Network condition is observed bythe agents at the runtime, and the power supplies are adjusted atdifferent granularity accordingly. This paper describes the systemarchitectures of two adaptive schemes, with efficient and feasiblealgorithms presented. Quantitative experiments demonstrate thatthey achieve superior power efficiency comparing with the basicarchitecture without any runtime configuration, while different tradeoffs are applied dependent on the monitoring granularity.
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| 7. |
- Yin, A. W., et al.
(författare)
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Hierarchical agent based NoC with dynamic online services
- 2009
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Ingår i: ICIEA. ; , s. 434-439
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Konferensbidrag (refereegranskat)abstract
- As the size of NoCs increases, power consumption and fault/variation tolerance have become two of the most crucial problems for system designers. To address these problems, we propose a NoC architecture based on a hierarchy of monitoring agents. By tracing the circuit properties at run time, the agents at different architectural levels are able to monitor and control over the whole NoC platform. This monitoring approach partitions various online diagnostic and management services onto hierarchical implementation levels so as to provide scalability and variability for large-scale NoC design. This paper explains the monitoring interaction between agent levels, and focuses on system optimization alternatives handled by different agent levels. It further quantitatively analyzes the feasibility and design alternatives in monitoring communication interconnection upon regular tile-based NoC layout.
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