Search results for "Ash"
showing 10 items of 1718 documents
Ein neues Fragment des Midrasch Bereschit Rabba
2021
Unter den in Archiven und Bibliotheken erhaltenen Einband- und Makulaturfragmenten bilden die auf Hebräisch beschrifteten Reste jüdischer Handschriften eine besondere Gruppe. Die Erforschung dieser jüdischen Fragmente erfährt seit einigen Jahren in Deutschland und auch in benachbarten europäischen Ländern zunehmende Beachtung. Dennoch sind viele Funde noch unbekannt und konnten daher etwa auch im Rahmen größerer Editionsprojekte nicht berücksichtigt werden. Ihre systematische Erfassung stellt daher nach wie vor eine wichtige Aufgabe dar und wird auch in den kommenden Jahren immer wieder interessante Entdeckungen auch an entlegenen Orten zu Tage fördern. Das hier vorgestellte Blatt wurde unl…
Concise and modular synthesis of regioisomeric haptens for the production of high-affinity and stereoselective antibodies to the strobilurin azoxystr…
2011
The immune response to regioisomeric haptens of azoxystrobin with varied derivatization sites was studied. Based on the Sonogashira and Suzuki-Miyaura couplings and following a straightforward modular design, we have synthesized four haptens with the same linker anchored through C-C bonds and located at different sites of the molecule. The most stereoselective antibodies were produced from immunogens with the spacer arm at a distal position from the β-methoxyacrylate moiety characteristic of strobilurins. Moreover, we observed that assay cross-reactivity was reliant on the functionalization site of the competitor derivative. Finally, the antibody binding site was explored using synthetic ch…
FADaC
2019
Solid state drives (SSDs) implement a log-structured write pattern, where obsolete data remains stored on flash pages until the flash translation layer (FTL) erases them. erase() operations, however, cannot erase a single page, but target entire flash blocks. Since these victim blocks typically store a mix of valid and obsolete pages, FTLs have to copy the valid data to a new block before issuing an erase() operation. This process therefore increases the latencies of concurrent I/Os and reduces the lifetime of flash memory. Data classification schemes identify data pages with similar update frequencies and group them together. FTLs can use this grouping to design garbage collection strategi…
Hot Impression Die Forging Process: An Approach to Flash Design for Tool Life Improvement
2005
In impression die forging the role of the flash geometry is fundamental since a proper design of the flash land strongly influences both the complete die filling and the die wear (i.e. the die life and the related costs). In this paper an integrated approach between numerical simulations and statistical tools was developed with the aim to optimize flash thickness in order to reduce die wear and to minimize material wasting. As wear is regarded, an analytical model depending on sliding velocity, temperature, die hardness and contact pressure was utilized during the numerical simulations of the process in order to reach a wear evaluation for different values of the flash design variables. Thu…
An Analysis of Flash Page Reuse With WOM Codes
2018
Flash memory is prevalent in modern servers and devices. Coupled with the scaling down of flash technology, the popularity of flash memory motivates the search for methods to increase flash reliability and lifetime. Erasures are the dominant cause of flash cell wear, but reducing them is challenging because flash is a write-once medium— memory cells must be erased prior to writing. An approach that has recently received considerable attention relies on write-once memory (WOM) codes, designed to accommodate additional writes on write-once media. However, the techniques proposed for reusing flash pages with WOM codes are limited in their scope. Many focus on the coding theory alone, whereas o…
Improving MLC flash performance and endurance with extended P/E cycles
2015
The traditional usage pattern for NAND flash memory is the program/erase (P/E) cycle: the flash pages that make a flash block are all programmed in order and then the whole flash block needs to be erased before the pages can be programmed again. The erase operations are slow, wear out the medium, and require costly garbage collection procedures. Reducing their number is therefore beneficial both in terms of performance and endurance. The physical structure of flash cells limits the number of opportunities to overcome the 1 to 1 ratio between programming and erasing pages: a bit storing a logical 0 cannot be reprogrammed to a logical 1 before the end of the P/E cycle. This paper presents a t…
<title>Managing compressed multimedia data in a memory hierarchy: fundamental issues and basic solutions</title>
1998
The purpose of the work is to discuss the fundamental issues and solutions in managing compressed and uncompressed multimedia data, especially voluminous continuous mediatypes (video, audio) and text in a memory hierarchy with four levels (main memory, magnetic disk, (optical or magnetic) on-line/near-line low-speed memory, and slow off-line memory, i.e. archive). We view the multimedia data in such a database to be generated, (compressed), and stored into the memory hierarchy (at the lowest non-archiving level), and subsequently retrieved, (decompressed), and presented. If unused, the data either travels down in the memory hierarchy or it is compressed and stored at the same level. We firs…
Comparison of TID response and SEE characterization of single- and multi-level high density NAND flash memories
2009
Heavy ion single-event measurements and total ionizing dose (TID) response for 8Gb commercial NAND flash memories are reported. Radiation results of multilevel flash technology are compared with results from single-level flash technology. The single-level devices are less sensitive to single event upsets (SEUs) than multi-level devices. In general, these commercial high density memories exhibit less TID degradation compared to older generations of flash memories. The charge pump in this study survived up to 600 krads.
Extending SSD lifetime in database applications with page overwrites
2013
Flash-based Solid State Disks (SSDs) have been a great success story over the last years and are widely used in embedded systems, servers, and laptops.One often overlooked ability of NAND flash is that flash pages can be overwritten in certain circumstances. This can be used to decrease wear out and increase performance.In this paper, we analyze the potential of overwrites for the most used data structure in database applications: the B-Tree. We show that with overwrites it is possible to significantly reduce flash wear out and increase overall performance.