The Efficacy of Error Mitigation Techniques for DRAM Retention Failures: A Comparative Experimental Study

As DRAM cells continue to shrink, they become more susceptible to retention failures. DRAM cells that permanently exhibit short retention times are fairly easy to identify and repair through the use of memory tests and row and column redundancy. However, the retention time of many cells may vary over time due to a property called Variable Retention Time (VRT). Since these cells intermittently transition between failing and non-failing states, they are particularly difficult to identify through memory tests alone. In addition, the high temperature packaging process may aggravate this problem as the susceptibility of cells to VRT increases after the assembly of DRAM chips. A promising alternative to manufacturetime testing is to detect and mitigate retention failures after the system has become operational. Such a system would require mechanisms to detect and mitigate retention failures in the field, but woul

Focal Spot, Spring 1993

https://digitalcommons.wustl.edu/focal_spot_archives/1063/thumbnail.jp

A Global Metabolic Shift Is Linked to Salmonella Multicellular Development

Bacteria can elaborate complex patterns of development that are dictated by temporally ordered patterns of gene expression, typically under the control of a master regulatory pathway. For some processes, such as biofilm development, regulators that initiate the process have been identified but subsequent phenotypic changes such as stress tolerance do not seem to be under the control of these same regulators. A hallmark feature of biofilms is growth within a self-produced extracellular matrix. In this study we used metabolomics to compare Salmonella cells in rdar colony biofilms to isogenic csgD deletion mutants that do not produce an extracellular matrix. The two populations show distinct metabolite profiles. Even though CsgD controls only extracellular matrix production, metabolite signatures associated with cellular adaptations associated with stress tolerances were present in the wild type but not the mutant cells. To further explore these differences we examine the temporal gene expression of genes implicated in biofilm development and stress adaptations. In wild type cells, genes involved in a metabolic shift to gluconeogenesis and various stress-resistance pathways exhibited an ordered expression profile timed with multicellular development even though they are not CsgD regulated. In csgD mutant cells, the ordered expression was lost. We conclude that the induction of these pathways results from production of, and growth within, a self produced matrix rather than elaboration of a defined genetic program. These results predict that common physiological properties of biofilms are induced independently of regulatory pathways that initiate biofilm formation

Comparison of milk production and fertility of dairy cows in conventional and ecological farms

Fertility and production traits of SRB and SLB cows in Swedish organic and conventional dairy production were compared in this study. Data were collected from the Swedish milk-recording system and the Swedish certification organization for organic production (KRAV). In the study 794 092 cow lactation records between year 1997 and 2002 were used. Four fertility measures were defined: number of days between calving and last insemination (cli), number of days between calving and first insemination (cfi), number of days between first and last insemination (fli) and number of inseminations per service period (nins). Three production measures were defined: 305-days milk yield (milk), fat yield (fat) and protein yield (prot). Only records from the first lactation were used. The most complete model included the effects of production system, year of lactation, herd-year size, season and milk yield as well as the two-way interactions between system and all main effects. In addition to that also the two-way interaction between year of lactation and herd-year size was analyzed. Without adjustment for milk yield in the model, both breeds had better fertility in organic production. However, when milk yield was included, only SLB had better fertility in organic production while SRB had better fertility in conventional production. The general trend over time showed that SLB has a deteriorating fertility and that fertility for both breeds was better in larger herds. The fertility deteriorates as the milk yield increases, this was a general trend except for the first milk class which deviated from the rest of the classes. There was no interaction between the effect of season and system on fertility. Cows calving in July-August were found to have best fertility, measured as calving to last insemination

Advanced Sensing, Fault Diagnostics, and Structural Health Management

Advanced sensing, fault diagnosis, and structural health management are important parts of the maintenance strategy of modern industries. With the advancement of science and technology, modern structural and mechanical systems are becoming more and more complex. Due to the continuous nature of operation and utilization, modern systems are heavily susceptible to faults. Hence, the operational reliability and safety of the systems can be greatly enhanced by using the multifaced strategy of designing novel sensing technologies and advanced intelligent algorithms and constructing modern data acquisition systems and structural health monitoring techniques. As a result, this research domain has been receiving a significant amount of attention from researchers in recent years. Furthermore, the research findings have been successfully applied in a wide range of fields such as aerospace, manufacturing, transportation and processes

2017 EACTS/EACTA Guidelines on patient blood management for adult cardiac surgery

Authors/Task Force Members: Christa Boer (EACTA Chairperson)(Netherlands), Michael I. Meesters (Netherlands), Milan Milojevic (Netherlands), Umberto Benedetto (UK), Daniel Bolliger (Switzerland), Christian von Heymann (Germany), Anders Jeppsson (Sweden), Andreas Koster (Germany), Ruben L. Osnabrugge (Netherlands), Marco Ranucci (Italy), Hanne Berg Ravn (Denmark), Alexander B.A. Vonk (Netherlands), Alexander Wahba (Norway), Domenico Pagano (EACTS Chairperson)(UK),. Document Reviewers: Moritz W.V. Wyler von Ballmoos (USA), Mate Petricevic (Croatia), Arie Pieter Kappetein (Netherlands), Miguel Sousa-Uva (Portugal), Georg Trummer (Germany), Peter M. Rosseel (Netherlands), Michael Sander (Germany), Pascal Colson (France), Adrian Bauer (Germany)

From experiment to design – fault characterization and detection in parallel computer systems using computational accelerators

This dissertation summarizes experimental validation and co-design studies conducted to optimize the fault detection capabilities and overheads in hybrid computer systems (e.g., using CPUs and Graphics Processing Units, or GPUs), and consequently to improve the scalability of parallel computer systems using computational accelerators. The experimental validation studies were conducted to help us understand the failure characteristics of CPU-GPU hybrid computer systems under various types of hardware faults. The main characterization targets were faults that are difficult to detect and/or recover from, e.g., faults that cause long latency failures (Ch. 3), faults in dynamically allocated resources (Ch. 4), faults in GPUs (Ch. 5), faults in MPI programs (Ch. 6), and microarchitecture-level faults with specific timing features (Ch. 7). The co-design studies were based on the characterization results. One of the co-designed systems has a set of source-to-source translators that customize and strategically place error detectors in the source code of target GPU programs (Ch. 5). Another co-designed system uses an extension card to learn the normal behavioral and semantic execution patterns of message-passing processes executing on CPUs, and to detect abnormal behaviors of those parallel processes (Ch. 6). The third co-designed system is a co-processor that has a set of new instructions in order to support software-implemented fault detection techniques (Ch. 7). The work described in this dissertation gains more importance because heterogeneous processors have become an essential component of state-of-the-art supercomputers. GPUs were used in three of the five fastest supercomputers that were operating in 2011. Our work included comprehensive fault characterization studies in CPU-GPU hybrid computers. In CPUs, we monitored the target systems for a long period of time after injecting faults (a temporally comprehensive experiment), and injected faults into various types of program states that included dynamically allocated memory (to be spatially comprehensive). In GPUs, we used fault injection studies to demonstrate the importance of detecting silent data corruption (SDC) errors that are mainly due to the lack of fine-grained protections and the massive use of fault-insensitive data. This dissertation also presents transparent fault tolerance frameworks and techniques that are directly applicable to hybrid computers built using only commercial off-the-shelf hardware components. This dissertation shows that by developing understanding of the failure characteristics and error propagation paths of target programs, we were able to create fault tolerance frameworks and techniques that can quickly detect and recover from hardware faults with low performance and hardware overheads

Die Populationsstruktur von Pseudomonas aeruginosa - neu überdacht unter Umwelt-Focus

In this work a population genetic study of more than 430 environmental strains of P. aeruginosa, mostly from river systems in Northern Germany but also from worldwide distributed sampling places is reported. We identify several genetic lineages, of which one is apparently of a predominantly environmental nature. We observe a non-random distribution in environmental habitats and we identified ecological criteria which may be explanatory for this. The results suggest that different selective pressures aid to drive the cladogenic split of evolutionary lineages within P. aeruginosa. This study shifts the clinically motivated (but from a global perspective rather narrow) focus of P. aeruginosa as an opportunistic pathogen to its rather true nature as an environmental organism.In dieser Arbeit wurde eine populationsgenetische Studie an mehr als 430 Umwelt-Stämmen von /Pseudomonas aeruginosa/ durchgeführt. Die Stämme stammten zum größten Teil aus Flusssystemen in Norddeutschland. Es wurden mehrere genetische Linien identifiziert, darunter eine offensichtlich besonders gut an die Umwelt angepasste Linie. Es zeigte sich, dass die Verteilung der Linien in verschiedenen Umwelt-Habitaten nicht gleichförmig war. Es konnten ökologische Kriterien identifiziert werden, die mögliche Ursachen für das beobachtete Verteilungsmuster darstellen können. Die Ergebnisse zeigen letztendlich, dass verschiedene Selektionsdrücke für das kladogenetische Aufspaltungsmuster der evolutiven Linien innerhalb der Art /P. aeruginosa/ verantwortlich sind. Diese Studie verschiebt somit das klinisch begründbare aber von einer globalen Perspektive her jedoch unzutreffende Verständnis von /P. aeruginosa/ als opportunistischem Krankheitserreger hin zu der tatsächlichen Darstellung von /P. aeruginosa/ als Umweltorganismus