Korkean luotettavuuden verkkohallinteiset laitteiden väliset yhteydet

Fifth generation cellular networks aim to provide new types of services. Prominent amongst these are industrial automation and vehicle-to-vehicle communications. Such new use cases demand lower latencies and higher reliability along with greater flexibility than current and past generations of cellular technologies allow. Enabling these new service types requires the introduction of device-to-device communications (D2D). This work investigated network-controlled D2D schemes wherein cellular base stations retain control over spectrum usage. D2D nodes assemble into clusters. Each D2D cluster then organises itself as it sees fit within the constraints imposed by the cellular network. A review of proposed D2D control schemes was conducted to identify pertinent interference issues. Measurements were then devised to empirically collect quantitative data on the impact of this interference. Measurements were conducted using a software-defined radio (SDR) platform. An SDR based system was selected to enable a low cost and highly flexible iterative approach to development while still providing the accuracy of real-world measurement. D2D functionality was added to the chosen SDR system with the essential parts of Long Term Evolution Release 8 implemented. Two series of measurements were performed. The first aimed to determine the adjacent channel interference impact of a cellular user being located near a D2D receiver. The second measurement series collected data on the co-channel interference of spectrum re-use between a D2D link and a moving cellular transmitter. Based on these measurements it was determined that D2D communications within a cellular system is feasible. Furthermore, the required frequency of channel state information reporting as a function of node velocity was determined.Viidennen sukupolven solukkoverkoilla pyritään mahdollistamaan uudentyyppisiä palveluja kuten teollisuusautomatiikkaa ja ajoneuvojen välistä viestintää. Tämänkaltaiset uudet käyttötarkoitukset vaativat lyhyempien viiveiden ja korkeammat luotettavuuden ohella myös suurempaa joustavuutta kuin minkä nykyisen sukupolven matkapuhelinverkkoteknologiat sallivat. Edellä mainittujen uusien palvelujen toteuttaminen vaatii suoria laitteiden välisiä yhteyksiä (engl. D2D). Tässä diplomityössä keskityttiin tutkimaan verkkohallinteisia D2D-rakenteita, joissa solukkoverkko hallinnoi spektrin käyttöä. D2D-päätteet liittyvät yhteen muodostaakseen klustereita, jotka hallinnoivat sisäistä tietoliikennettään parhaaksi katsomallaan tavalla solukkoverkon asettamien rajoitusten puitteissa. Kirjallisuuskatsauksen avulla selvitettiin aiemmissa tutkimuksissa esitetyille D2D-ratkaisuille yhteiset interferenssiongelmat. Näiden vaikutusta ja suuruutta tutkittiin mittausten avulla. Mittaukset toteutettiin ohjelmistoradioalustan (engl. SDR) avulla. SDR-pohjaisen järjestelmän käyttö mahdollisti edullisen ja joustavan tavan kerätä empiirisiä mittaustuloksia. D2D-toiminnallisuus lisättiin Long Term Evolution Release 8:n olennaiset ominaisuudet omaavaan alustaan. Tällä alustalla toteutettiin kaksi mittaussarjaa. Ensimmäisellä kerättiin tuloksia viereisellä kanavalla toimivan matkapuhelimen D2D-vastaanottimelle aiheuttamasta interferenssistä näiden ollessa toistensa läheisyydessä. Toisella mittaussarjalla selvitettiin samalla kanavalla toimivan D2D-yhteyden ja liikkuvan matkapuhelimen välistä interferenssiä. Mittausten perusteella todettiin D2D-toiminnallisuuden lisäämisen solukkoverkkoon olevan mahdollista. Lisäksi laskettiin vaadittava kanavalaadun päivitystiheys päätteiden nopeuden funktiona

Tuberculostearic Acid-Containing Phosphatidylinositols as Markers of Bacterial Burden in Tuberculosis

One-fourth of the global human population is estimated to be infected with strains of the Mycobacterium tuberculosis complex (MTBC), the causative agent of tuberculosis (TB). Using lipidomic approaches, we show that tuberculostearic acid (TSA)-containing phosphatidylinositols (PIs) are molecular markers for infection with clinically relevant MTBC strains and signify bacterial burden. For the most abundant lipid marker, detection limits of ∼10$^{2}$ colony forming units (CFUs) and ∼10$^{3}$ CFUs for bacterial and cell culture systems were determined, respectively. We developed a targeted lipid assay, which can be performed within a day including sample preparation─roughly 30-fold faster than in conventional methods based on bacterial culture. This indirect and culture-free detection approach allowed us to determine pathogen loads in infected murine macrophages, human neutrophils, and murine lung tissue. These marker lipids inferred from mycobacterial PIs were found in higher levels in peripheral blood mononuclear cells of TB patients compared to healthy individuals. Moreover, in a small cohort of drug-susceptible TB patients, elevated levels of these molecular markers were detected at the start of therapy and declined upon successful anti-TB treatment. Thus, the concentration of TSA-containing PIs can be used as a correlate for the mycobacterial burden in experimental models and in vitro systems and may prospectively also provide a clinically relevant tool to monitor TB severity

Aerosol forcing in the Climate Model Intercomparison Project (CMIP5) simulations by HadGEM2-ES and the role of ammonium nitrate

The latest Hadley Centre climate model, HadGEM2-ES, includes Earth system components such as interactive chemistry and eight species of tropospheric aerosols. It has been run for the period 1860–2100 in support of the fifth phase of the Climate Model Intercomparison Project (CMIP5). Anthropogenic aerosol emissions peak between 1980 and 2020, resulting in a present-day all-sky top of the atmosphere aerosol forcing of −1.6 and −1.4 W m−2 with and without ammonium nitrate aerosols, respectively, for the sum of direct and first indirect aerosol forcings. Aerosol forcing becomes significantly weaker in the 21st century, being weaker than −0.5 W m−2 in 2100 without nitrate. However, nitrate aerosols become the dominant species in Europe and Asia and decelerate the decrease in global mean aerosol forcing. Considering nitrate aerosols makes aerosol radiative forcing 2–4 times stronger by 2100 depending on the representative concentration pathway, although this impact is lessened when changes in the oxidation properties of the atmosphere are accounted for. Anthropogenic aerosol residence times increase in the future in spite of increased precipitation, as cloud cover and aerosol-cloud interactions decrease in tropical and midlatitude regions. Deposition of fossil fuel black carbon onto snow and ice surfaces peaks during the 20th century in the Arctic and Europe but keeps increasing in the Himalayas until the middle of the 21st century. Results presented here confirm the importance of aerosols in influencing the Earth's climate, albeit with a reduced impact in the future, and suggest that nitrate aerosols will partially replace sulphate aerosols to become an important anthropogenic species in the remainder of the 21st century

Multiscale Effects of Interfacial Polymer Confinement in Silica Nanocomposites

Dispersing hydrophilic nanofillers in highly hydrophobic polymer matrices is widely used to tune the mechanical properties of composite material systems. The ability to control the dispersion of fillers is closely related to the mechanical tunability of such composites. In this work, we investigate the physical–chemical underpinnings of how simple end-group modification to one end of a styrene–butadiene chain modifies the dispersion of silica fillers in a polymer matrix. Using surface-sensitive spectroscopies, we directly show that polymer molecular orientation at the silica surface is strongly constrained for silanol functionalized polymers compared to nonfunctionalized polymers because of covalent interaction of silanol with silica. Silanol functionalization leads to reduced filler aggregation in composites. The results from this study demonstrate how minimal chemical modifications of polymer end groups are effective in modifying microstructural properties of composites by inducing molecular ordering of polymers at the surface of fillers

Metamodernism, the Anthropocene, and the Resurgence of Historicity: Ben Lerner’s 10:04 and “the utopian glimmer of fiction”

Postmodernism has been characterized by a reductive presentism that suppresses historicity and neglects the possibility of the future. If we have seen a shift from postmodernism to a different cultural logic and structure of feeling—as, indeed, many critics argue—it therefore follows that this may also entail a new dominant in temporal dynamics. In this article, I take Ben Lerner’s 2014 novel 10:04 as a case study in literary metamodernism, though I also make reference to Adam Thirlwell’s 2011 novella Kapow! and Ruth Ozeki’s 2013 novel A Tale for the Time Being. Across these texts, and primarily in 10:04 as a quintessentially metamodernist fiction, I observe and explicate a metamodern temporality characterized, interconnectedly, by the aesthetics of heterochrony, sideshadowing, and the anticipation of retrospection. Whilst this temporal dynamic emerges from the precarity and volatility of experience in the twenty-first century, anthropocenic climate change has been and remains—I suggest—the greatest catalyst in producing this new temporal experience which resurrects historicity and resuscitates the future as a field of possibilities

Iterative reconstruction incorporating background correction improves quantification of [18F]-NaF PET/CT images of patients with abdominal aortic aneurysm

Background A confounding issue in [18F]-NaF PET/CT imaging of abdominal aortic aneurysms (AAA) is the spill in contamination from the bone into the aneurysm. This study investigates and corrects for this spill in contamination using the background correction (BC) technique without the need to manually exclude the part of the AAA region close to the bone. Methods Seventy-two (72) datasets of patients with AAA were reconstructed with the standard ordered subset expectation maximization (OSEM) algorithm incorporating point spread function (PSF) modelling. The spill in effect in the aneurysm was investigated using two target regions of interest (ROIs): one covering the entire aneurysm (AAA), and the other covering the aneurysm but excluding the part close to the bone (AAAexc). ROI analysis was performed by comparing the maximum SUV in the target ROI (SUVmax(T)), the corrected cSUVmax (SUVmax(T) − SUVmean(B)) and the target-to-blood ratio (TBR = SUVmax(T)/SUVmean(B)) with respect to the mean SUV in the right atrium region. Results There is a statistically significant higher [18F]-NaF uptake in the aneurysm than normal aorta and this is not correlated with the aneurysm size. There is also a significant difference in aneurysm uptake for OSEM and OSEM + PSF (but not OSEM + PSF + BC) when quantifying with AAA and AAAexc due to the spill in from the bone. This spill in effect depends on proximity of the aneurysms to the bone as close aneurysms suffer more from spill in than farther ones. Conclusion The background correction (OSEM + PSF + BC) technique provided more robust AAA quantitative assessments regardless of the AAA ROI delineation method, and thus it can be considered as an effective spill in correction method for [18F]-NaF AAA studies

Software-defined Communication Platform Implementation on Commodity Hardware

Radio access networks face increasingly diversified and strict demands from applications. The diverse needs of users cannot be satisfied by a single approach. Networks must evolve into flexible platforms offering per-user service customized to the needs of each application. Meeting the increased coverage and capacity demands of applications also requires network densification. Mobile network operators are confronted with the need to improve their service offerings while keeping the capital and operational expenditure of densified networks under control. Expanding the network using traditional base station designs presents cost and interference challenges. Introducing a functional split between central and distributed units enables better co-ordination and cheaper distributed units situated closer to cell sites. This thesis contributes to software-based soft—real-time radio access networks (RAN) implementation using commodity hardware. Techniques are presented for implementing software-defined radio nodes effectively. The overall aim is to exploit the benefits of commodity hardware while mitigating the challenges caused by its focus on throughput and polyvalency over low latency and determinism. This work details an architecture for decoupling the communication protocol code from the underlying platform. The approach used is to hide and recover from deadline misses instead of being overly conservative in an effort to provide guarantees. The benefits afforded by increased flexibility in the RAN outweigh occasional lost data due to deadline overruns. The strict requirements on latency imposed by the time domain structure of air interface protocol creates challenges for power management. A method for latency-aware power management is proposed to help solve this. Building on the above, this thesis also investigates disaggregated multi-node RAN implementations. Dividing RAN functionality into physically separate nodes introduces additional latency. The midhaul linking these nodes together becomes an important factor of performance analysis. The research in this thesis presents models for characterizing the behaviour of the midhaul. Models provide tools to assess which functional splits are suitable for a particular scenario. The validity of the techniques and models presented in this thesis are verified through the use of testbeds. Prototype implementations show the viability of building soft—real-time software-based RANs on commodity hardware. The feasibility of midhaul-based disaggregated designs is demonstrated through the use of user equipment positioning as a test application. The results obtained show soft—real-time commodity hardware designs can enable novel RAN architectures

Scheduling Latency of Midhaul-based Commodity Hardware C-RAN

| openaire: EC/H2020/815191/EU//PriMO-5GThe impact of midhaul-induced latency on the performance of a wireless communication system must be understood in order to be appropriately accounted for. To this end, we study the impact of midhaul delay and jitter on the scheduling of a cloud radio access network. A soft–real-time commodity hardware testbed is used to gather data using up to 16 virtualized distributed units. The empirical data is used to develop models to analyze the midhaul latency’s impact on spectral efficiency and outage probability. Modeling takes into account the burstiness of deadline misses in order to replicate outage duration in addition to frequency. The recorded data is then used to derive an estimate of system scaling in terms of shortest transmission time interval supported for a set number of distributed units for a given deadline miss rate. Results show that scaling behavior depends on the target rate. More stringent targets emphasize the impact of tail latencies. The testbed suffers less than 0.1 % spectral efficiency loss from deadline misses at a transmission time interval duration of 500 μs with 16 distributed units.Peer reviewe

Latency-Aware Power Management in Software-Defined Radios

| openaire: EC/H2020/815191/EU//PriMO-5GCloud computing provides benefits in terms of equipment consolidation and power savings from higher utilization for virtualizable software. Cellular communication software faces challenges in cloud computing platforms. BSs create a specific load profile that differs from traditional cloud service loads. Cellular communication system implementations have real-time deadlines with fixed, periodic latency requirements. In this paper, we assess the suitability of an unmodified Ubuntu Linux OS running on a commodity server to operate latency-critical software using a 4G LTE BS software-defined radio implementation. Scaling of the CPU clock frequency is shown to be feasible without excessive impact on the platform's ability to meet the 4 ms processing delay requirement imposed by the LTE standard. Measurements show the relationship between the processor's operating frequency and the number of missed subframe processing deadlines to be nonlinear. The results obtained also indicate that a high computational capacity does not suffice to ensure satisfactory operation since fronthaul processing overhead can limit achievable performance. Use of offload-capable network interface cards is studied as a potential remedy.Peer reviewe