A data-oriented network architecture

In the 25 years since becoming commercially available, the Internet has grown into a global communication infrastructure connecting a significant part of mankind and has become an important part of modern society. Its impressive growth has been fostered by innovative applications, many of which were completely unforeseen by the Internet's inventors. While fully acknowledging ingenuity and creativity of application designers, it is equally impressive how little the core architecture of the Internet has evolved during this time. However, the ever evolving applications and growing importance of the Internet have resulted in increasing discordance between the Internet's current use and its original design. In this thesis, we focus on four sources of discomfort caused by this divergence. First, the Internet was developed around host-to-host applications, such as telnet and ftp, but the vast majority of its current usage is service access and data retrieval. Second, while the freedom to connect from any host to any other host was a major factor behind the success of the Internet, it provides little protection for connected hosts today. As a result, distributed denial of service attacks against Internet services have become a common nuisance, and are difficult to resolve within the current architecture. Third, Internet connectivity is becoming nearly ubiquitous and reaches increasingly often mobile devices. Moreover, connectivity is expected to extend its reach to even most extreme places. Hence, applications' view to network has changed radically; it's commonplace that they are offered intermittent connectivity at best and required to be smart enough to use heterogeneous network technologies. Finally, modern networks deploy so-called middleboxes both to improve performance and provide protection. However, when doing so, the middleboxes have to impose themselves between the communication end-points, which is against the design principles of the original Internet and a source of complications both for the management of networks and design of application protocols. In this thesis, we design a clean-slate network architecture that is a better fit with the current use of the Internet. We present a name resolution system based on name-based routing. It matches with the service access and data retrieval oriented usage of the Internet, and takes the network imposed middleboxes properly into account. We then propose modest addressing-related changes to the network layer as a remedy for the denial of service attacks. Finally, we take steps towards a data-oriented communications API that provides better decoupling for applications from the network stack than the original Sockets API does. The improved decoupling both simplifies applications and allows them to be unaffected by evolving network technologies: in this architecture, coping with intermittent connectivity and heterogenous network technologies is a burden of the network stack

Recursive SDN for Carrier Networks

Control planes for global carrier networks should be programmable (so that new functionality can be easily introduced) and scalable (so they can handle the numerical scale and geographic scope of these networks). Neither traditional control planes nor new SDN-based control planes meet both of these goals. In this paper, we propose a framework for recursive routing computations that combines the best of SDN (programmability) and traditional networks (scalability through hierarchy) to achieve these two desired properties. Through simulation on graphs of up to 10,000 nodes, we evaluate our design's ability to support a variety of routing and traffic engineering solutions, while incorporating a fast failure recovery mechanism

Flow caching for high entropy packet fields

Packet classification on general purpose CPUs remains expensive regardless of advances in classification algorithms. Unless the packet forwarding pipeline is both simple and static in function, fine-tuning the system for optimal forwarding is a time-consuming and brittle process. Network virtualization and network function virtual-ization value general purpose CPUs exactly for their flexibility: in such systems, a single x86 forwarding element does not implement a single, static classification step but a sequence of dynamically reconfigurable and potentially complex forwarding operations. This leaves a software developer looking for maximal packet forwarding throughput with few options besides flow caching. In this paper, we consider the problem of flow caching and more specifically, how to cache forwarding decisions that depend on packet fields with high entropy (and therefore, change often); to this end, we arrive at algorithms that allow us to efficiently compute near optimal flow cache entries spanning several transport connections, even if forwarding decisions depend on transport protocol headers. Categories and Subject Descriptor

Effects of reindeer grazing and recovery after cessation of grazing on the ground-dwelling spider assemblage in Finnish Lapland

The effect of reindeer Rangifer tarandus L. grazing on the ground-dwelling spider assemblage in Northern Finland was studied. Changes in species richness, abundance and evenness of spider assemblages were analyzed in relation to changes in vegetation and environmental factors in long term grazed and ungrazed sites as well as sites that had recently switched from grazed to ungrazed and vice versa. Grazing was found to have a significant impact on height and biomass of lichens and other ground vegetation. However, it seemed not to have an impact on the total abundance of spiders. This is likely caused by opposing family and species level responses of spiders to the grazing regime. Lycosid numbers were highest in grazed and linyphiid numbers in ungrazed areas. Lycosidae species richness was highest in ungrazed areas whereas Linyphiidae richness showed no response to grazing. Four Linyphiidae, one Thomisidae and one Lycosidae species showed strong preference for specific treatments. Sites that had recovered from grazing for nine years and the sites that were grazed for the last nine years but were previously ungrazed resembled the long term grazed sites. The results emphasize the importance of reindeer as a modifier of boreal forest ecosystems but the impact of reindeer grazing on spiders seems to be family and species specific. The sites with reversed grazing treatment demonstrate that recovery from strong grazing pressure at these high latitudes is a slow process whereas reindeer can rapidly change the conditions in previously ungrazed sites similar to long term heavily grazed conditions.</p

Label-free characterization and real-time monitoring of cell uptake of extracellular vesicles

Extracellular vesicles (EVs) have the ability to function as molecular vehicles and could therefore be harnessed to deliver drugs to target cells in diseases such as cancer. The composition of EVs determines their function as well as their interactions with cells, which consequently affects the cell uptake efficacy of EVs. In this study, we present two novel label-free approaches for studying EVs; characterization of EV composition by time-gated surface-enhanced Raman spectroscopy (TG-SERS) and monitoring the kinetics and amount of cellular uptake of EVs by surface plasmon resonance (SPR) in real-time. Using these methods, we characterized the most abundant EVs of human blood, red blood cell (RBC)- and platelet (PLT)-derived EVs and studied their interactions with prostate cancer cells. Complementary studies were performed with nanoparticle tracking analysis for concentration and size determinations of EVs, zeta potential measurements for surface charge analysis, and fluorophore-based confocal imaging and flow cytometry to confirm EV uptake. Our results revealed distinct biochemical features between the studied EVs and demonstrated that PLT-derived EVs were more efficiently internalized by PC-3 cells than RBC-derived EVs. The two novel label-free techniques introduced in this study were found to efficiently complement conventional techniques and paves the way for further use of TG-SERS and SPR in EV studies.Peer reviewe

Future Combustion Technology for Synthetic and Renewable Fuels in Compression Ignition Engines (REFUEL) - Final report

This domestic project, Future Combustion Technology for Synthetic and Renewable Fuels in Compression Ignition Engines (ReFuel), was part of a Collaborative Task "Future Combustion Technology for Synthetic and Renewable Fuels in Transport" of International Energy Agency (IEA) Combustion Agreement. This international Collaborative Task is coordinated by Finland. The three-year (2009-2011) project was a joint research project with Aalto University (Aalto), Tampere University of Technology (TUT), Technical Research Centre of Finland (VTT) and Åbo Akademi University (ÅAU). The project was funded by TEKES, Wärtsilä Oyj, Neste Oil Oyj, Agco Sisu Power, Aker Arctic Technology Oy and the research partners listed above. Modern renewable diesel fuels have excellent physical and chemical properties, in comparison to traditional crude oil based fuels. Purely paraffinic fuels do not contain aromatic compounds and they are totally sulphur free. Hydrotreated Vegetable Oil (HVO) was studied as an example of paraffinic high cetane number (CN) diesel fuels. HVO has no storage and low temperature problems like the fatty acid methyl esters (FAMEs) have. The combustion properties are better than those of crude oil based fuels and FAME, because they have very high cetane numbers and contain no polyaromatic hydrocarbons (PAH). With low HVO density, viscosity and distillation temperatures, these advantageous properties allow far more advanced combustion strategies, such as very high exhaust gas recirculation (EGR) rates or extreme Miller timings, than has been possible with current fossil fuels. The implementation of these advanced combustion technologies, together with the novel renewable diesel fuel, brought significant nitrogen oxides (NOx), particulate matter (PM) emission reductions with no efficiency losses. The objective of ReFuel project was to develop new extremely low emission combustion technologies for new renewable fuels in compression ignition engines. The target was to decrease emissions at least by 70%. The scope was to utilize the physical and chemical properties of the renewable fuels that differ from properties of the traditional crude oil based fuels and to develop optimum combustion technologies for them. The project focused firstly, on paraffinic high cetane number fuels i.e. hydrotreated vegetable oil fuel as a typical representative of this kind of fuel and secondly, on fuels with high content of oxygenates. This was implemented by blending oxygenate to HVO fuel.

Mitä tietoa Suomessa saadaan hoitoilmoitusrekistereistä ja mitä väestötutkimuksista? : Kansanterveyden seuranta, arviointi ja ennakointi

Vertaisarvioitu. English summary.Lähtökohdat : Väestön terveyden ja hyvinvoinnin seurannassa on tulevaisuudessa tärkeää väestö¬tutkimusten ohella hyödyntää rekisteritietoja. Tämä vaatii ymmärrystä tietojen luotettavuudesta erilaisten ilmiöiden kuvaajina. Menetelmät : FinTerveys 2017 -tutkimukseen osallistuneiden tutkimustietoja ja hoitoilmoitusrekistereistä saatuja tietoja verrattiin muutaman keskeisen sairauden ja riskitekijän yleisyyden arvioinnissa. Tulokset : Diabeteksen, sepelvaltimotaudin, astman ja keuhkoahtaumataudin yleisyydet olivat tutkitussa väestössä lähes samanlaisia sekä väestötutkimustiedon että rekisteritiedon perusteella. Masennusta tunnistettiin rekisteritietojen perusteella selvästi vähemmän kuin tutkimustietojen perusteella. Hoitoilmoitus¬rekisterien tiedot olivat täysin puutteellisia kohonneen verenpaineen ja lihavuuden tunnistamiseen. Päätelmät : Arviot sellaisten sairauksien yleisyydestä, jotka vaativat jatkuvaa seurantaa ja säännöllistä lääkitystä, ovat hyvin samanlaisia sekä rekisteri- että tutkimustiedon perusteella. Hoitoilmoitusrekisterien tieto ei sen sijaan anna luotettavaa kuvaa terveysriskien yleisyydestä.Peer reviewe

Kansanterveyden seuranta, arviointi ja ennakointi : mitä tietoa Suomessa saadaan hoitoilmoitusrekistereistä ja mitä väestötutkimuksista?

Lähtökohdat : Väestön terveyden ja hyvinvoinnin seurannassa on tulevaisuudessa tärkeää väestö­tutkimusten ohella hyödyntää rekisteritietoja. Tämä vaatii ymmärrystä tietojen luotettavuudesta erilaisten ilmiöiden kuvaajina.Menetelmät : FinTerveys 2017 -tutkimukseen osallistuneiden tutkimustietoja ja hoitoilmoitusrekistereistä saatuja tietoja verrattiin muutaman keskeisen sairauden ja riskitekijän yleisyyden arvioinnissa.Tulokset : Diabeteksen, sepelvaltimotaudin, astman ja keuhkoahtaumataudin yleisyydet olivat tutkitussa väestössä lähes samanlaisia sekä väestötutkimustiedon että rekisteritiedon perusteella. Masennusta tunnistettiin rekisteritietojen perusteella selvästi vähemmän kuin tutkimustietojen perusteella. Hoitoilmoitus­rekisterien tiedot olivat täysin puutteellisia kohonneen verenpaineen ja lihavuuden tunnistamiseen.Päätelmät : Arviot sellaisten sairauksien yleisyydestä, jotka vaativat jatkuvaa seurantaa ja säännöllistä lääkitystä, ovat hyvin samanlaisia sekä rekisteri- että tutkimustiedon perusteella. Hoitoilmoitusrekisterien tieto ei sen sijaan anna luotettavaa kuvaa terveysriskien yleisyydestä

Multispectral photon-counting for medical imaging and beam characterization - A project review

Central focus of the MPMIB project – funded via the Academy of Finland’s RADDESS 2018–2021 programme – has been research towards a next-generation radiation detection system operating in a photon-counting (PC) multispectral mode: The extraction of energy spectrum per detector pixel data will lead to better efficacy in medical imaging with ionizing radiation. Therefore, it can be an important asset for diagnostic imaging and radiotherapy, enabling better diagnostic outcome with lower radiation dose as well as more versatile characterization of the radiation beam, leading for example to more accurate patient dosimetry. We present our approach of fabricating direct-conversion detectors based on cadmium telluride (CdTe) semiconductor material hybridized with PC mode capable application-specific integrated circuits (ASICs), and will give a review on our achievements, challenges and lessons learned. The CdTe crystals were processed at Micronova, Finland’s national research infrastructure for micro- and nanotechnology, employing techniques such as surface passivation via atomic layer deposition, and flip chip bonding of processed sensors to ASIC. Although CdTe has excellent photon radiation absorption properties, it is a brittle material that can include large concentrations of defects. We will therefore also emphasize our quality assessment of CdTe crystals and processed detectors, and present experimental data obtained with prototype detectors in X-ray and Co-60 beams at a standards laboratoryPeer reviewe