Implementation of the page fault frequency replacement algorithm.

This paper investigates the implementation of the page fault frequency (PFF) replacement algorithm as the mechanism for selecting and replacing pages of programs loaded into the main memory of a multiprocessing, multiprogrammed computer system. The frequency at which an executing program requires a page of virtual memory, the PFF, provides a basis for judging the real memory requirements of the program. Operating difficulties of PFF that reduce its usefulness in a time-shared computer system (Michigan Terminal System) are discussed, and a means of implementing the algorithm is proposed.http://archive.org/details/implementationof00lancCaptain, United States Marine CorpsApproved for public release; distribution is unlimited

逆想起を用いた形態学的連想記憶モデルに関する研究

九州工業大学博士学位論文 学位記番号:生工博甲第241号 学位授与年月日:平成27年3月25日第1章 序論|第2章 連想記憶モデル|第3章 記銘パターンから独立した核パターンを用いたMAM|第4章 逆想起を用いたMAM|第5章 分割記銘により計算量を抑えた逆想起を用いたMAM|第6章 結論九州工業大学平成26年

The role of H3K4 methyltransferases in Drosophila memory

Gene transcription required for long-term memory requires the modification of histones. However, there are still many uncertainties about the identity and spatial expression of genes regulated by histone modifications during memory related processes. In this project I examined the role of Drosophila melanogaster methyltransferases Set1 and trx in courtship memory. Genetic knockdown of Set1 and trx in the mushroom body (MB) revealed that Set1 was necessary for short- and long-term memory, while trx was only required for long-term memory. Transcriptional profiling of MBs following trx-knockdown revealed expression changes in MB-enriched genes and genes involved in RNA processing. Among the MB-enriched genes altered in trx-knockdown, Ldh exhibited dramatically reduced expression relative to control flies. Preliminary tests showed that Ldh-knockdown resulted in reduced courtship memory. Therefore, Ldh is likely a downstream effector of trx-regulated memory function. The results of this study provide novel insight into histone methyltransferase function in memory

Near Data Processing for Efficient and Trusted Systems

We live in a world which constantly produces data at a rate which only increases with time. Conventional processor architectures fail to process this abundant data in an efficient manner as they expend significant energy in instruction processing and moving data over deep memory hierarchies. Furthermore, to process large amounts of data in a cost effective manner, there is increased demand for remote computation. While cloud service providers have come up with innovative solutions to cater to this increased demand, the security concerns users feel for their data remains a strong impediment to their wide scale adoption. An exciting technique in our repertoire to deal with these challenges is near-data processing. Near-data processing (NDP) is a data-centric paradigm which moves computation to where data resides. This dissertation exploits NDP to both process the data deluge we face efficiently and design low-overhead secure hardware designs. To this end, we first propose Compute Caches, a novel NDP technique. Simple augmentations to underlying SRAM design enable caches to perform commonly used operations. In-place computation in caches not only avoids excessive data movement over memory hierarchy, but also significantly reduces instruction processing energy as independent sub-units inside caches perform computation in parallel. Compute Caches significantly improve the performance and reduce energy expended for a suite of data intensive applications. Second, this dissertation identifies security advantages of NDP. While memory bus side channel has received much attention, a low-overhead hardware design which defends against it remains elusive. We observe that smart memory, memory with compute capability, can dramatically simplify this problem. To exploit this observation, we propose InvisiMem which uses the logic layer in the smart memory to implement cryptographic primitives, which aid in addressing memory bus side channel efficiently. Our solutions obviate the need for expensive constructs like Oblivious RAM (ORAM) and Merkle trees, and have one to two orders of magnitude lower overheads for performance, space, energy, and memory bandwidth, compared to prior solutions. This dissertation also addresses a related vulnerability of page fault side channel in which the Operating System (OS) induces page faults to learn application's address trace and deduces application secrets from it. To tackle it, we propose Sanctuary which obfuscates page fault channel while allowing the OS to manage memory as a resource. To do so, we design a novel construct, Oblivious Page Management (OPAM) which is derived from ORAM but is customized for page management context. We employ near-memory page moves to reduce OPAM overhead and also propose a novel memory partition to reduce OPAM transactions required. For a suite of cloud applications which process sensitive data we show that page fault channel can be tackled at reasonable overheads.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144139/1/shaizeen_1.pd

Space station data system analysis/architecture study. Task 2: Options development DR-5. Volume 1: Technology options

The second task in the Space Station Data System (SSDS) Analysis/Architecture Study is the development of an information base that will support the conduct of trade studies and provide sufficient data to make key design/programmatic decisions. This volume identifies the preferred options in the technology category and characterizes these options with respect to performance attributes, constraints, cost, and risk. The technology category includes advanced materials, processes, and techniques that can be used to enhance the implementation of SSDS design structures. The specific areas discussed are mass storage, including space and round on-line storage and off-line storage; man/machine interface; data processing hardware, including flight computers and advanced/fault tolerant computer architectures; and software, including data compression algorithms, on-board high level languages, and software tools. Also discussed are artificial intelligence applications and hard-wire communications

Organocatalytic synthesis of chiral non-racemic aziridines, labelled with 2H, 15N, 13C stable isotopes

Aziridines are ‘keystone’ synthetic building blocks - relatively reactive, three-membered heterocycles with the potential for generating ‘secondary’ high value entities such as α- or β-amino acids via ring-opening reactions. Within this thesis, a one-pot asymmetric organocatalytic methodology is utilised for the synthesis of enantiomerically enriched cis-N-aryl-3-aryl-aziridine-2-carboxylates, labelled with stable isotopes: 2H, 13C and 15N. The reactions were catalysed by (S)-BINOL derived N-triflylphosphoramide Brønsted acid and stable isotopes were selectively introduced within an aziridine ring with > 95% isotopic enrichment. The desired compounds were generated in yields of up to 81% and up to 87% e.e. Furthermore optically active β-bromo-α-amino acid derivatives were generated via aziridine ring-opening methodology without loss of the isotopic label or e.e. α-Arylglycinols are α-amino-β-alcohols, that can be found as structural motifs in synthetic and natural compounds or used as building blocks to access other functional groups. When oxidised, α-arylglycinols are converted to the α-arylglycines - a class of α-amino acids found in a wide range of bioactive compounds such as vancomycin and teicoplanin glycopeptide antibiotics. Successful incorporation of 2H or 13C stable isotopes at α- or β-positions of enantiomerically enriched N-Cbz protected α-arylglycinols is reported with > 95% isotopic enrichment, yields of up to 73% and up to 98% e.e. Teicoplanin is a glycopeptide antibiotic, used against methicillin-resistant Staphylococcus aureus (MRSA), but the emerging bacterial resistance has escalated the search for new antibiotics. The synthesis of a non-labelled model fragment of the glycopeptide antibiotic teicoplanin is reported. The fragment is synthesised via an aziridination reaction and can be used as a template to generate teicoplanin analogues, both non-labelled and labelled with stable isotopes. It is anticipated that the stable isotope incorporating methodologies described within this thesis will be applicable not only to the synthesis of novel glycopeptide antibiotics, but also to other biologically active compounds. The installation of stable isotopes affords compounds with highly valuable properties that can be used to study drug metabolism, toxicology, pharmacokinetics and reaction mechanisms

A multi-agent crop production decision support system for technology transfer

The purpose of this research was to study agricultural crop production 'decision support systems' as a means of transferring agricultural technology from research labs and plots to producers, extension specialists, agriculture service agencies, and scientists, on the Western Canadian Prairies. A 'decision support system' is a computer program that analyses problems spanning several knowledge or problem areas producing results that aid the management decision-making process. The primary objective was to develop a computer application program that would fulfill the farm manager's decision support needs and be "open" to future enhancements. This interdisciplinary study has a strong agricultural presence in the application context of the resultant computerized agricultural decision support system, with agronomics being the foundation on which the system was built, and computer science being the toolbox used to build it. Farm Smart 2000 is the resultant decision support system, providing "single-window" access to three different tiers of decision support utilizing the Internet, ' expert systems' and integrated multiple heterogeneous 'reusable agents' in a cooperative problem-solving environment. An ' expert system' is a computer program that solves complicated problems, within a specific knowledge or problem area, that would otherwise require human expertise. Expert systems integrated with each other within a decision support system are called 'agents. Reusable agents' are modular computer programs (e.g. expert systems) which can be used in more than one computer application with little or no modification. Farm Smart 2000 provides support for most management aspects of crop production including variety selection, crop rotations, weed management, disease management, residue management, harvesting, soil conservation, and economics, for the crops of wheat, canola, barley, peas, and flax. Tier-3, the most sophisticated level of Farm Smart 2000, is the focus of this dissertation and utilizes multiple reusable agents, integrating them such that they cooperate together to solve complex interrelated crop production problems. A Global Control Expert achieves the required communication and coordination among the agents resulting in an "open system", enabling Farm Smart 2000 to extend its problem-solving capabilities by integrating additional agents and knowledge, without system re-engineering, thereby remaining an ongoing technology transfer vehicle

Artificial intelligence : a heuristic search for commercial and management science applications

Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1984.MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY.Bibliography: leaves 185-188.by Philip A. Cooper.M.S