Universiẗat, Diss., 1997--Gießen.

Universiẗat, Diss., 2000--München.

Task scheduling in operating system area is well known problem on traditional system architectures (NUMA, SMP). However, it does not perform well on emerging many-core architectures, especially on Intel Xeon Phi. We have collected all publicly available information about the Xeon Phi's architecture. After that we have benchmarked the Xeon Phi to find missing information about its architecture. We were especially curious in architecture of cores and memory controllers. These parts are most important while designing scheduler. Based on the measured results we have proposed improvements to scheduling algorithm in the Bobox - experimental streaming system. Powered by TCPDF (www.tcpdf.org)

Task scheduling in operating system area is a well-known problem on traditional system architectures (NUMA, SMP). Unfortunately, it does not perform well on emerging many-core architectures, especially on Intel Xeon Phi. We collected all publicly available information about the architecture of Xeon Phi. After that, we benchmarked the Xeon Phi in order to find the missing information about its architecture. We focused especially on the information about cores and memory controllers. These are the most important parts when designing a scheduler. Based on the results, we proposed improvements for scheduling algorithm in the Bobox (an experimental streaming system). However, we found that the biggest problem is not in the scheduling algorithm, but in the design of operators' parallelization. Therefore, we proposed improvements to the parallelization and tested one of the proposals.

Intracellular pH (pHi) impacts many cellular mechanisms including cellular metabolism, gene expression, cell volume regulation, cell survival and proliferation. Most cells use two general pHi regulatory mechanisms: HCO3-/Cl- antiporters (AE, Slc4a family) to reduce internal alkaline load, and Na+/H+ exchangers (NHE, Slc9a family) that protect cells from acidosis. Previous studies with preimplantation (PI) embryos have shown robust activity of HCO3-/Cl- exchanger in all stages of development. It was also determined that inhibition of this exchange with the stilbene AE inhibitor 4,4’-diisothiocyanostilbene-2,2’-disulfonic acid (DIDS) was detrimental to embryo development from the 2‐cell stage to blastocyst when cultured at high external pH. In this study I investigated which of the five known plasma membrane NHE isoforms was present and active within mouse PI embryos and their role as pHi regulators throughout preimplantation embryo development. In mouse oocytes and preimplantation embryos, mRNAs were detected encoding NHE1 (SLC9A1), NHE3 (SLC9A3), and NHE4 (SLC9A4), with higher mRNA levels for each in fully-grown oocytes through one-cell stage embryos and then generally lower levels after the two-cell stage. No transcripts for NHE2 (SLC9A2) or NHE5 (SLC9A5) were detected. Measurements of intracellular pH during recovery from acidosis, induced by transient ammonium pulse, suggested that recovery occurred and was mediated by NHE activity at all preimplantation stages assessed (one-cell, two-cell, eight-cell and morula). This recovery was inhibited by 1 mM amiloride, a general NHE inhibitor. The observed residual recovery was attributed to passive passage of protons across the membrane, rather than the activity of NHE4 (an amiloride-resistant isoform), since no further decrease in recovery rates from acidosis was observed upon amiloride increase to 5 mM. Furthermore, recovery from acidosis at each stage was entirely inhibited by cariporide, which is very highly selective for NHE1. In contrast, the moderately NHE3-selective inhibitor S3226 did not preferentially block recovery, nor did adding S3226 increase inhibition over that achieved with cariporide alone, indicating that NHE3 did not play a functional role in pHi regulation at any stage assessed. Another regulator of intracellular pH against acidosis, previously reported to be active in oocytes and 1-cell embryos, the sodium-dependent bicarbonate/chloride exchanger (NDBCE; SLC4A8), had low or absent activity in two-cell embryos. This indicated that NHE1 is likely the only significant regulator of pHi in preimplantation mouse embryos, at least after the 1-cell stage. Culturing embryos from the one-cell or two-cell stages in acidotic medium inhibited their development, as assessed by development to the blastocyst stage and cell lineage allocation. However, inhibition of NHE1 with cariporide, NDBCE with DIDS, or both together did not further decrease embryo development to the blastocyst stage more extensively under conditions of chronic acidosis than at normal pH. This suggests that mouse PI embryos have a restricted ability to counteract chronic acidosis by means of pHi regulatory mechanisms, despite clearly being able to recover from acute acidosis via NHE1 activity.

Indiana University-Purdue University Indianapolis (IUPUI) / FGF23 is an osteocyte produced hormone necessary for maintaining systemic phosphate handling, and thus bone structure and function in both rare and common disorders such as chronic kidney disease (CKD). FGF23 is a critical factor in CKD, with elevated levels causing alterations in mineral metabolism and increased odds for mortality. However, the mechanisms directing the production of key modulators of skeletal homeostasis and biomineralization within osteocytes, and how this is altered in chronic kidney disease, remain unclear. The experimental focus of this dissertation was to dissect the molecular systems and role of oxygen sensing in the regulated production of FGF23. In CKD, up to 75% of patients have anemia and concomitant marked elevations in FGF23, increasing mortality odds. Anemia is a potent driver of FGF23 secretion, therefore, current and emerging therapies, including recombinant EPO and the hypoxia inducible factorprolyl hydroxylase inhibitors (HIF-PHI) FG-4592 and BAY 85-3934, were used to improve anemia in the adenine diet-induced mouse model of CKD. In the mice with CKD, iFGF23 was markedly elevated in control mice but was attenuated by 65-85% after delivery of EPO or HIF-PHI, with no changes in serum phosphate. This was associated with improved systemic iron utilization and reductions in mRNA markers of renal fibrosis. In osteocyte-like cell cultures treated with HIF-PHI, integrative RNAseq and ATACseq analysis identified candidate genes upregulated in response to mimicked hypoxia, concomitant with elevated Fgf23 expression. These genes were found to be downregulated in CKD bone, therefore, knock-out cells were generated using CRISPR/Cas9 technology. These cells were found to be functionally similar to in vivo conditional knockout models that have enhanced bone mass and elevated FGF23. Taken together, these results further define novel factors involved in the regulation of FGF23 and identify new therapeutic targets. / 2023-05-26

The study was conducted to identify characteristics that are associated with successful transfer to institutions of higher learning from 3 Phi Theta Kappa chapters at a large multi-campus Mississippi community college. The study examined participation rates and transfer rates of Phi Theta Kappa students. The current study also identified student characteristics that predict the successful transfer of Phi Theta Kappa members. A correlational methodological approach was employed. The Phi Theta Kappa chapters in this study have significant differences in membership, yet the factors that predict transfer to a 4-year university or college are few. The factors include age at transfer, cumulative grade point average, type of major, and associate degree completion. The analysis resulted in a model that may be used to predict the probability that a Phi Theta Kappa student will be a successful transfer. The model was able to predict the transfer of these students with significantly higher probabilities than the baseline model.

No description available.

La caractérisation des applications en vue de les préparer pour les nouvelles architectures et les porter sur des systèmes très étendus est une étape importante pour pouvoir anticiper les modifications nécessaires. Comme les machines Exascale sont prévues pour la période 2018-2020, l'étude des applications et leur préparation pour ces machines s'avèrent donc essentielles. Nous nous intéressons aux applications d'imagerie sismique et en particulier à l'application Reverse Time Migration (RTM) car elle est très utilisée par les pétroliers dans le cadre de l'exploration sismique.La première partie de nos travaux a porté sur l'étude du cœur de calcul de l'application RTM qui consiste en un calcul de différences finies dans le domaine temporel (FDTD). Nous avons caractérisé cette partie de l'application en soulevant les aspects architecturaux des machines actuelles ayant un fort impact sur la performance, notamment les caches, les bandes passantes et le prefetching. Cette étude a abouti à l'élaboration d'un modèle de performance permettant de prédire le trafic DRAM des FDTD. La deuxième partie de la thèse se focalise sur l'impact de l'hétérogénéité et le parallélisme sur la FDTD et sur RTM. Nous avons choisi l'architecture manycore d’Intel, Xeon Phi, et nous avons étudié une implémentation "native" et une implémentation hétérogène et hybride, la version "symmetric". Enfin, nous avons porté l'application RTM sur un cluster hétérogène, Stampede du Texas Advanced Computing Center (TACC), où nous avons effectué des tests de scalabilité allant jusqu'à 64 nœuds contenant des coprocesseurs Xeon Phi et des processeurs Sandy Bridge ce qui correspond à presque 5000 cœurs / As we are expecting Exascale systems for the 2018-2020 time frame, performance analysis and characterization of applications for new processor architectures and large scale systems are important tasks that permit to anticipate the required changes to efficiently exploit the future HPC systems. This thesis focuses on seismic imaging applications used for modeling complex physical phenomena, in particular the depth imaging application called Reverse Time Migration (RTM). My first contribution consists in characterizing and modeling the performance of the computational core of RTM which is based on finite-difference time-domain (FDTD) computations. I identify and explore the major tuning parameters influencing performance and the interaction between the architecture and the application. The second contribution is an analysis to identify the challenges for a hybrid and heterogeneous implementation of FDTD for manycore architectures. We target Intel’s first Xeon Phi co-processor, the Knights Corner. This architecture is an interesting proxy for our study since it contains some of the expected features of an Exascale system: concurrency and heterogeneity.My third contribution is an extension of the performance analysis and modeling to the full RTM. This adds communications and IOs to the computation part. RTM is a data intensive application and requires the storage of intermediate values of the computational field resulting in expensive IO accesses. My fourth contribution is the final measurement and model validation of my hybrid RTM implementation on a large system. This has been done on Stampede, a machine of the Texas Advanced Computing Center (TACC), which allows us to test the scalability up to 64 nodes each containing one 61-core Xeon Phi and two 8-core CPUs for a total close to 5000 heterogeneous cores

På Hedlunda i Umeå finns Hedlunda förskola; en byggnad som innehåller förskoleverksamhet, ett storkök och en matsal. Byggnaden uppfördes 2014 och började nyttjas samma år. Byggnaden är projekterad av Sweco för att klara krav gällande allt från specialpedagogik till energi och miljö. Den är även certifierad enligt en internationell passivhusstandard. Syftet med examensarbetet är att granska om förskolan håller de energikrav den projekterats för, samt att jämföra byggnadens projekterade energianvändning med den i praktiken uppmätta. Det sistnämnda gjordes även för att utvärdera precisionen hos den projekterade energianvändningen. Energibehovet ställdes även i proportion till de gränsvärden för energikrav som används av andra energicertifieringar. Byggnaden simulerades i programmet IDA ICE, och de mätvärden som samlades in bearbetades i Microsoft Excel. Programmet PHPP användes även för att granska om förskolan uppfyllde de internationella passivhuskraven. Byggnaden klarar varken kravet för årlig energianvändning eller kravet för specifikt primärenergibehov. Båda dessa är krav inom den internationella passivhusstandarden. Det föregående överskrids med 14 %, och det senare med 4 %. Byggnaden klarar energikravet för den svenska passivhuscertifieringen med god marginal. Värdet på byggnadens specifika energianvändning skilde sig knappt alls mellan projekteringen och det uppmätta värdet. Tittar man dock på enskilda faktorer så skiljer sig de projekterade värdena av el och uppvärmning sig mot de uppmätta med större differenser. Störst differens återfinns i faktorn verksamhetsel som överskattades med 60 % i projekteringen. Byggnadens specifika energianvändning uppgick till ca 43 kWh /m2 år  vilket är lägre kraven de vanligaste energistandardena ställer, vilket innebär att byggnaden är osedvanligt energieffektiv. Om alla lokaler som fick bygglov i Sverige 2015 hade byggts med samma energiprestanda som denna byggnad så hade det gått åt 392 GWh /år , medan om de istället byggts enligt BBRs standard så hade energiåtgången blivit 1098 GWh /år  (exklusive verksamhetsel). Även om olika lokaler har olika behov och krav så ger det en fingervisning av besparingspotentialen. Syftet med byggnaden var att det skulle bli en förebild för framtida energisnåla projekt, vilket det också blev när Vegaskolan i Vännäs byggdes efter samma koncept. På det hela taget är Hedlunda förskola en byggnad med hög energiprestanda. / At Hedlunda in Umeå, there’s a building complex containing a combined preschool, canteen and catering kitchen. It was built in 2014 and the preschool started up the same year. Sweco projected the building to satisfy the requisites required for the international passive house certification. The building was also supposed to meet specific requirements for specialized pedagogy, and requirements for non-toxic building materials in preschools, amongst others. In this master thesis the building’s energy usage was studied to see if the building met the requested requirements, and how close the estimated energy demand was to the actual demand. The purchased energy was also compared to energy requirements used by other certification systems used in Sweden today. The building meets the international passive house requirement for the annual heating demand, but breaches the requirement for primary energy value by 4 %. The Swedish passive house requirement is met with a significant margin. The purchased energy per square meter was 43 kWh /m2 year , which differed only marginally from the projected value of 41 kWh /m2 year . It may seem as if it was a very good estimation of the purchased energy, but when the factors are studied individually there are differences among them that go up to 60 %. The purchased energy per square meter was lower than all of the other requirements in other energy certification systems which proves that this is a highly efficient building. The building was created with the main purpose of serving as a model for energy efficient buildings, and it has served its purpose since Vegaskolan in Vännäs was built within the same concept. All in all, Hedlunda preschool is a building with a very good energy performance. If all public buildings who gained building permit in 2015 in Sweden had been built with the same energy efficiency as Hedlunda preschool, then the total energy demand would be 392 GWh /year , whereas if they were built as the BBR-standard the corresponding energy demand would be 1098 GWh /year . This is just a rough estimation to give a hint of the amount of energy that can be saved.