419 research outputs found
Persistent Memory Programming Abstractions in Context of Concurrent Applications
The advent of non-volatile memory (NVM) technologies like PCM, STT,
memristors and Fe-RAM is believed to enhance the system performance by getting
rid of the traditional memory hierarchy by reducing the gap between memory and
storage. This memory technology is considered to have the performance like that
of DRAM and persistence like that of disks. Thus, it would also provide
significant performance benefits for big data applications by allowing
in-memory processing of large data with the lowest latency to persistence.
Leveraging the performance benefits of this memory-centric computing technology
through traditional memory programming is not trivial and the challenges
aggravate for parallel/concurrent applications. To this end, several
programming abstractions have been proposed like NVthreads, Mnemosyne and
intel's NVML. However, deciding upon a programming abstraction which is easier
to program and at the same time ensures the consistency and balances various
software and architectural trade-offs is openly debatable and active area of
research for NVM community.
We study the NVthreads, Mnemosyne and NVML libraries by building a concurrent
and persistent set and open addressed hash-table data structure application. In
this process, we explore and report various tradeoffs and hidden costs involved
in building concurrent applications for persistence in terms of achieving
efficiency, consistency and ease of programming with these NVM programming
abstractions. Eventually, we evaluate the performance of the set and hash-table
data structure applications. We observe that NVML is easiest to program with
but is least efficient and Mnemosyne is most performance friendly but involves
significant programming efforts to build concurrent and persistent
applications.Comment: Accepted in HiPC SRS 201
Why musical memory can be preserved in advanced Alzheimer's disease
Musical memory is relatively preserved in Alzheimer's disease and other dementias. In a 7 Tesla functional MRI study employing multi-voxel pattern analysis, Jacobsen et al. identify brain regions encoding long-term musical memory in young healthy controls, and show that these same regions display relatively little atrophy and hypometabolism in patients with Alzheimer's disease.See Clark and Warren (doi:10.1093/brain/awv148) for a scientific commentary on this article.
Musical memory is relatively preserved in Alzheimer's disease and other dementias. In a 7 Tesla functional MRI study employing multi-voxel pattern analysis, Jacobsen et al. identify brain regions encoding long-term musical memory in young healthy controls, and show that these same regions display relatively little atrophy and hypometabolism in patients with Alzheimer's disease.See Clark and Warren (doi:10.1093/awv148) for a scientific commentary on this article
Could a well-designed customs reforms remove the trade-off between revenue collection and trade facilitation?
This paper is based on first-hand experience from Customs reforms in Sub Saharan Africa (SSA) and presents unpublished data on the impact of Customs reforms on revenues, trade facilitation, private sector operators and frontline Customs officials behaviors in Africa. Customs agencies are usually one of the key revenue collection agencies in Africa. Customs officials usually consider trade facilitation measures as a threat for revenue collection and strive to increase control over private sector operators through systematic inspections and checkpoints in order to increase public revenues (in theory). In reality, imports undervaluation remains high as well as smuggling and transit diversion, which result in endemic corruption and increased clearance time and uncertainty. Because many issues lie in the internal weaknesses of Customs agencies, a revised approach to Customs reforms is needed to ensure, first, internal control of the organization and then gradually relax controls on operators and ensure formal trade facilitation. Without internal control and knowledge of the magnitude of the malpractices in most Customs agencies in Africa, private sector differentiation can not happen and therefore formal trade facilitation would remain inexistent, while results in terms of revenue collection will probably be below what can be achieved. --Customs,trade facilitation,Nigeria,Cameroon,public sector reform
Grazing activities and biodiversity history in the Pyrénées - new insights on high altitude ecosystems in the framework of a Human-Environment Observatory
International audienceReconstruction of the relationship between pastoral activities and vegetation history in the central Pyrenees demonstrates the importance of grazing pressure in the maintenance of floristic diversity in highland regions that have been abandone
Analysis of a battery management system (BMS) control strategy for vibration aged nickel manganese cobalt oxide (NMC) Lithium-Ion 18650 battery cells
Electric vehicle (EV) manufacturers are using cylindrical format cells as part of the vehicle’s rechargeable energy storage system (RESS). In a recent study focused at determining the ageing behavior of 2.2 Ah Nickel Manganese Cobalt Oxide (NMC) Lithium-Ion 18650 battery cells, significant increases in the ohmic resistance (RO) were observed post vibration testing. Typically a reduction in capacity was also noted. The vibration was representative of an automotive service life of 100,000 miles of European and North American customer operation. This paper presents a study which defines the effect that the change in electrical properties of vibration aged 18650 NMC cells can have on the control strategy employed by the battery management system (BMS) of a hybrid electric vehicle (HEV). It also proposes various cell balancing strategies to manage these changes in electrical properties. Subsequently this study recommends that EV manufacturers conduct vibration testing as part of their cell selection and development activities so that electrical ageing characteristics associated with road induced vibration phenomena are incorporated to ensure effective BMS and RESS performance throughout the life of the vehicle
Predicting optimal hematocrit in silico
Optimal hematocrit maximizes oxygen transport. In healthy humans, the
average hematocrit is in the range of 40-45, but it can significantly
change in blood pathologies such as severe anemia (low ) and polycythemia
(high ). Whether the hematocrit level in humans corresponds to the optimal
one is a long standing physiological question. Here, using numerical
simulations with the Lattice Boltzmann method and two mechanical models of the
red blood cell (RBC) we predict the optimal hematocrit, and explore how
altering the mechanical properties of RBCs affects . We develop a
simplified analytical theory that accounts for results obtained from numerical
simulations and provides insight into the physical mechanisms determining
. Our numerical and analytical models can easily be modified to
incorporate a wide range of mechanical properties of RBCs as well as other soft
particles thereby providing means for the rational design of blood substitutes.
Our work lays the foundations for systematic theoretical study of the optimal
hematocrit and its link with pathological RBCs associated with various diseases
(e.g. sickle cell anemia, diabetes mellitus, malaria, elliptocytosis)
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