Secondary Memories Research Articles

Design of plasmonic enhanced all-optical phase-change memory for secondary storage applications

Phase-change optical device has recently gained tremendous interest due to its ultra-fast transmitting speed, multiplexing and large bandwidth. However, majority of phase-change optical devices are only devoted to on-chip components such as optical tensor core and optical main memory, while developing a secondary storage memory in an optical manner is rarely reported. To address this issue, we propose a novel phase-change optical memory based on plasmonic resonance effects for secondary storage applications. Such design makes use of the plasmonic dimer nanoantenna to generate plasmonic resonance inside the chalcogenide alloy, and thus enables the performance improvements in terms of energy consumption and switching speed. It is found that choosing height, radius, and separation of the plasmonic nanoantenna as 10 nm, 150 nm, and 10 nm, respectively, allows for a write/erase energies of 100 and 240 pJ and a write/erase speed of 10 ns for crystallization and amorphization processes, respectively. Such performance merits encouragingly prevail conventional secondary storage memories and thus pave a route towards the advent of all-optical computer in near future.

Feminist and Materialist Philosophies of History in Caryl Churchill’s Top Girls

The first act of Caryl Churchill’s Top Girls does away with temporal boundaries, inviting women across historical periods, artistic masterworks, and literary epics to a dinner party. During the evening, the women share their life stories, interrupt each other, and attempt to be heard over the roar of their fellow guests. In some ways, it resembles an indecipherable oral history. What is history if not indecipherable? It is the role of the historian to wade through primary and secondary sources, cultural memories and forgotten artifacts, in order to construct a written, visual, or auditory historical narrative. Thus, a history as we consume it, although based in fact, necessarily relies on narrative structure. Top Girls reminds us that history is like any other narrative: shaped by social, political, and economic forces; made unintelligible, fantastical, and surreal at times, by representative modes and their failings. By playing with the notion of history, notably combining fictional and historical figures in the first act, Top Girls emphasizes the claim that history is, among other things, reliant on both factual and fictional elements, like concrete dates and narrative structures. Top Girls narrows in on two models of historical narratives: the feminist history and materialist history. In this play, there are only women onstage. Women picture, or reference, the men in their past and present—an alcoholic father, a lousy ex-husband, an insecure coworker, Rocky Mountain Jim, and the Emperor of Japan—but a man never sets foot on stage. Only women enter and exit, only women go to and from work, only women tell their histories, signaling Churchill’s dual interest in a Marxist philosophy of history and the notion of a feminist history, which emerged in the feminist movement in the ‘70s and ‘80s. Through the dramatic form, which provides a fantastical element, Churchill animates and complicates history as a feminist and socialist practice.

Where Does Niklas Luhmann’s Card Index Come From?

Thanks to a grant of the Nordrhein-Westfälische Akademie der Wissenschaften und der Künste, Bielefeld University has started a fifteen-year project (2015–2030) that includes the production of a critical edition of Niklas Luhmann’s extant works and manuscripts, as well as the digitalization of his famous card index. This valuable enterprise has rekindled interest in what many scholars hold to be a ‘holy grail’: a marvelous instrument that aided great creativity and scientific production by the German sociologist. Indeed, people feel that looking inside the filing cabinet is like looking inside the mind of a genius at work. This article suggests a different point of view, rooted in the Enlightenment project of the sociologist of Bielefeld. The main hypothesis is that in the use of a card index as a surprise generator, there is nothing particularly surprising if one considers the evolution of knowledge management in early modern Europe. Rather, the question should be: how it is possible to explain the evolutionary improbability of the social use of ‘machines’ as secondary memories for knowledge management and reproduction? This article provides some suggestions for research and tries to determine where Luhmann’s card index comes from.

Associative memory cells and their working principle in the brain.

The acquisition, integration and storage of exogenous associated signals are termed as associative learning and memory. The consequences and processes of associative thinking and logical reasoning based on these stored exogenous signals can be memorized as endogenous signals, which are essential for decision making, intention, and planning. Associative memory cells recruited in these primary and secondary associative memories are presumably the foundation for the brain to fulfill cognition events and emotional reactions in life, though the plasticity of synaptic connectivity and neuronal activity has been believed to be involved in learning and memory. Current reports indicate that associative memory cells are recruited by their mutual synapse innervations among co-activated brain regions to fulfill the integration, storage and retrieval of associated signals. The activation of these associative memory cells initiates information recall in the mind, and the successful activation of their downstream neurons endorses memory presentations through behaviors and emotion reactions. In this review, we aim to draw a comprehensive diagram for associative memory cells, working principle and modulation, as well as propose their roles in cognition, emotion and behaviors.

Commonalities and Differences in the Substrates Underlying Consolidation of First- and Second-Order Conditioned Fear.

Consolidation of newly formed fear memories requires a series of molecular events within the basolateral complex of the amygdala (BLA). Once consolidated, new information can be assimilated into these established associative networks to form higher-order associations. Much is known about the molecular events involved in consolidating newly acquired fear memories but little is known about the events that consolidate a secondary fear memory. Here, we show that, within the male rat BLA, DNA methylation and gene transcription are crucial for consolidating both the primary and secondary fear memories. We also show that consolidation of the primary, but not the secondary, fear memory requires de novo protein synthesis in the BLA. These findings show that consolidation of a fear memory and its updating to incorporate new information recruit distinct processes in the BLA, and suggest that DNA methylation in the BLA is fundamental to consolidation of both types of conditioned fear.SIGNIFICANCE STATEMENT Our data provide clear evidence that a different set of mechanisms mediate consolidation of learning about cues that signal learned sources of danger (i.e., second-order conditioned fear) compared with those involved in consolidation of learning about cues that signal innate sources of danger (i.e., first-order conditioned fear). These findings carry important implications because second-order learning could underlie aberrant fear-related behaviors (e.g., in anxiety disorders) as a consequence of neutral secondary cues being integrated into associative fear networks established through first-order pairings, and thereby becoming potent conditioned reinforcers and predictors of fear. Therefore, our data suggest that targeting such second-order conditioned triggers of fear may require pharmacological intervention different to that typically used for first-order conditioned cues.

Traveling via Rome through the Stereoscope: Reality, Memory, and Virtual Travel

Underwood and Underwood’s Rome through the Stereoscope of 1902 was a landmark in stereoscopic photography publishing, both as an intense, visually immersive experience and as a cognitively demanding exercise. The set consisted of a guidebook, forty-six stereographs, and five maps whose notations enabled the reader/viewer to precisely replicate the location and orientation of the photographer at each site. Combined with the extensive narrative within the guidebook, the maps and images guided its users through the city via forty-six sites, whether as an example of armchair travel or an actual travel companion. The user’s experience is examined and analyzed within the following parameters: the medium of stereoscopic photography, narrative, geographical imagination, and memory, bringing forth issues of movement, survey and route frames of reference, orientation, visualization, immersion, and primary versus secondary memories. Rome through the Stereoscope was an example of virtual travel, and the process of fusing dual images into one — stereoscopic synthesis — further demarcated the experience as a virtual environment.

Building Entity Relationship Models for PDDL and Developing Planners Based on Stored Procedures

PDF HTML阅读 XML下载 导出引用 引用提醒 PDDL 的ER 建模以及开发基于存储过程的规划器 DOI: 10.3724/SP.J.1001.2013.04264 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(61003179, 61100134); 广东省自然科学基金(S2011040001427) Building Entity Relationship Models for PDDL and Developing Planners Based on Stored Procedures Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:随着智能规划的发展,其所面对的问题规模越来越大,而且可以预见以后会更大.现有的研究大多用二级存储扩展空间,其终极形式应该是用数据库进行存储.此外,有很多同一领域的规划问题,其所包含的常量几乎一致,其中必然有可重用信息来帮助加速求解.要更好地利用这些可重用信息也需要数据库.考虑到以上两个问题,首次提出规划领域描述语言PDDL(planning domain description language)的ER 模型(entity relationship model),并基于此模型用存储过程来编写规划器SPP(stored procedure planner).SPP 是完全在数据库内部运行的最优规划器,存取效率高,可充分利用数据库的各种功能.在国际规划大赛IPC(Int’l planning competition)基准领域上的实验结果表明,在有限的机器配置下,SPP 可以求解传统最优规划器不能求解的问题.该工作迈出了在数据库中求解规划问题,从而彻底解决空间问题的第一步. Abstract:With the development of automated planning, the size of problems is getting bigger and bigger, and one can predict that it will become very large in the future. Some existing research work begins to use secondary memories to extend the search space, and it is believed databases are finally used. Besides, many problems that belong to the same domain often have common constants, so there might be a plenty of reusable information to speed up the solution process. To store this information permanently, databases are also needed. Inspired by the above two reasons, this paper first proposes ER (entity relationship) models for PDDL (planning domain description languages) and then develops a stored procedure based automated planner (stored procedure planner, SPP) for the first time. This planner is an optimal one which runs totally inside a database. It stores and accesses data efficiently and takes fully advantages of database features. Experiments on benchmark problems from the Int'l planning competition (IPC) show that this planner can solve problems which cannot be solved by some classical optimal planners in a limited machine configuration. The work in this paper takes the first step for solving planning problems totally in a database so that it is helpful to solve huge-size problems finally. 参考文献 相似文献 引证文献

The perils of being a borderland people: on the Lhotshampas of Bhutan

This article responds to Baud and van Schendel's call for research into the history of borderland people in order to redress ‘the imbalance of “state-centred” studies’. It does so by providing a study of borderlands from the periphery, analysing the experiences of the Lhotshampas – a borderland people of Bhutan – who migrated there from Nepal and India a few generations ago. In response to the Bhutanese Government's efforts to promote a homogeneous national identity during the 1980s, Lhotshampa political leaders campaigned for increased political and cultural rights. The suppression of their early protests by the Bhutanese authorities ushered in a period of instability and conflict in the south, eventually resulting in the exodus of tens of thousands of refugees who have been living in camps in Nepal since the early 1990s. Through the use of secondary literature and refugees' memories, the article investigates the perspectives of ordinary villagers caught between the Bhutanese state and local elite political activists. It highlights the important role that oral histories can play in furthering our understanding of social and political dynamics in borderland areas.

The effects of early post-hatching changes of imprinting object on the pattern of monocular/unihemispheric sleep of domestic chicks

The pattern of monocular/unihemispheric sleep (Mo–Un sleep) was studied behaviourally in male and female chicks after early post-hatching changes of the imprinting object. Chicks were reared with an imprinting object on day 1 post-hatching which was removed or changed on day 2. On day 1, time spent in binocular sleep (both eyes closed) was similar in male and female chicks, though the number of episodes was lower in females than in males. There was no eye-closure bias in the pattern of Mo–Un sleep (one eye shut and the other open) in chicks of both sexes. On day 2, chicks subjected to the removal of imprinting object showed less time and number of episodes of binocular sleep than control chicks and chicks subjected to changes of imprinting object. There was no eye-closure bias in control chicks whilst a significant bias for more right Mo–Un sleep was recorded in chicks after removal and changes of imprinting object of both sexes. It is suggested that the removal or changes of imprinting object would cause a decrease of binocular sleep and trigger processes associated to secondary imprinting involving the left hemisphere. The bias for more right Mo–Un sleep (right eye-closure) could be the by-product of consolidation processes of secondary imprinting memories in the left hemisphere and/or of more left eye-opening as a result of periodical awakening of right hemisphere to control the environment after a stressful condition such as the removal or change of imprinting object.

Efficient Out-of-Core Algorithms for Linear Relaxation Using Blocking Covers

When a numerical computation fails to fit in the primary memory of a serial or parallel computer, a so-called “out-of-core” algorithm, which moves data between primary and secondary memories, must be used. In this paper, we study out-of-core algorithms for sparse linear relaxation problems in which each iteration of the algorithm updates the state of every vertex in a graph with a linear combination of the states of its neighbors. We give a general method that can save substantially on the I/O traffic for many problems. For example, our technique allows a computer withMwords of primary memory to performT=Ω(M1/5) cycles of a multigrid algorithm for a two-dimensional elliptic solver over an n-point domain using onlyΘ(nT/M1/5) I/O transfers, as compared with the naive algorithm which requiresΩ(nT) I/O's. Our method depends on the existence of a “blocking” cover of the graph that underlies the linear relaxation. A blocking cover has the property that the subgraphs forming the cover have large diameters once a small number of vertices have been removed. The key idea in our method is to introduce a variable for each removed vertex for each time step of the algorithm. We maintain linear dependences among the removed vertices, thereby allowing each subgraph to be iteratively relaxed without external communication. We give a general theorem relating blocking covers to I/O-efficient relaxation schemes. We also give an automatic method for finding blocking covers for certain classes of graphs, including planar graphs andd-dimensional simplicial graphs with constant aspect ratio (i.e., graphs that arise from dividingd-space into “well-shaped” polyhedra). As a result, we can performTiterations of linear relaxation on anyn-vertex planar graph using onlyΘ(n+nTlgn/M1/4) I/O's or on anyn-noded-dimensional simplicial graph with constant aspect ratio using onlyΘ(n+nTlgn/MΩ(1/d)) I/O's.

SELAC—statistical error location and correction for secondary memory storage

In this paper a statistical approach to error location and correction for data stored in secondary memories is developed. The approach is based on the observation that the data records in secondary storage have some inherent redundancy of information. This redundancy cannot precisely be predicted as in the case of typical error correction scheme's artificial redundancy. However, the redundancy can be exploited to provide error correction with some degree of confidence. We use simple and weighted checksum schemes for error detection and present algorithms for single and multiple error correction using statistical error location and correction (SELAC). An implementation of SELAC will be described with an elaborate study of its error-correction capabilities. A conspicuous aspect of SELAC is that it will not cost any processor time and storage overhead until after an error is encountered, unlike the classical schemes using single error correcting-double error detecting (SEC-DED) and double error correcting-triple error detecting (DEC-TED) codes.

Efficient branch-and-bound algorithms on a two-level memory system

Branch-and-bound algorithms in a system with a two-level memory hierarchy were evaluated. An efficient implementation depends on the disparities in the numbers of subproblems expanded between the depth-first and best-first searches as well as the relative speeds of the main and secondary memories. A best-first search should be used when it expands a much smaller number of subproblems than that of a depth-first search, and the secondary memory is relatively slow. In contrast, a depth-first search should be used when the number of expanded subproblems is close to that of a best-first search. The choice is not as clear for cases in between these cases are studied. Two strategies are proposed and analyzed: a specialized virtual-memory system that matches the architectural design with the characteristics of the existing algorithm, and a modified branch-and-bound algorithm that can be tuned to the characteristic of the problem and the architecture. The latter strategy illustrates that designing a better algorithm is sometimes more effective that tuning the architecture alone. >

Computer Hardware Design Projects for Undergraduate Students

A laboratory-based approach is described for making a diversified set of computer hardware design projects available to large groups of undergraduate students at a modest cost. Memory and input/output functions are provided as common resources to groups of students using either minicomputer or microcomputer systems. These computer systems also serve vital functions of providing interactive operating and testing aids to students, such as issuing prompts for actions by the students, loading internal secondary and external primary main memories, postmortem dumping of main memory, diagnosing input/output errors, and, in some cases, loading an external control memory. Students connect to this common-resource computer system via a programmable bidirectional parallel interface that was designed for the purpose of implementing communications between computing machines in a flexible and low-cost manner.

The technology of error-correcting codes

This paper is a survey of error-correcting codes, with emphasis on the costs of encoders and decoders, and the relationship of these costs to various important system parameters such as speed and delay. Following an introductory overview, the remainder of this paper is divided into three sections corresponding to the three major types of channel noise: white Gaussian noise, interference, and digital errors of the sort which occur in secondary memories such as disks. Appendix A presents some of the more important facts about modern implementations of decoders for long high-rate Reed-Solomon codes, which play an important role throughout the paper. Appendix B investigates some important aspects of the tradeoffs between error correction and error detection.

Hardware method for context searching in intelligent secondary memory

Considerable interest has recently evolved in the development of machines for searching large databases. The study of architectures for these machines has combined the studies of associative memories, intelligent secondary memories and database management systems. The term, nonnumeric architecture has been given to this study. Unlike the Von Neuman architecture, which is based on a numeric operator, this new architecture will be oriented to searching operations.

On imaginary fields, token transfers and floating codes in intelligent secondary memories

In analyzing two implemented intelligent secondary memories, CASSM and RAP, we recognize a common mechanism which is here called an imaginary field. The mechanism can be generalized to suggest further design possibilities. It further explains the complex and controversial CASSM mechanism, “pointer transfer” in terms of separate but related principles—imaginary fields, token transfers, and floating codes—such that further designs can utilize some or all of the techniques.

On imaginary fields, token transfers and floating codes in intelligent secondary memories

In analyzing two implemented intelligent secondary memories, CASSM and RAP, we recognize a common mechanism which is here called an imaginary field. The mechanism can be generalized to suggest further design possibilities. It further explains the complex and controversial CASSM mechanism, “pointer transfer” in terms of separate but related principles—imaginary fields, token transfers, and floating codes—such that further designs can utilize some or all of the techniques.

On imaginary fields, token transfers and floating codes in intelligent secondary memories

In analyzing two implemented intelligent secondary memories, CASSM and RAP, we recognize a common mechanism which is here called an imaginary field. The mechanism can be generalized to suggest further design possibilities. It further explains the complex and controversial CASSM mechanism, “pointer transfer” in terms of separate but related principles—imaginary fields, token transfers, and floating codes—such that further designs can utilize some or all of the techniques.

A Self Managing Secondary Memory system

A Self Managing Secondary Memory (SMSM) organization is proposed herein, in which hardware directly assists the storage, retrieval and management of arbitrary length records on such devices as fixed head discs or charge coupled devices (CCD's). This paper emphasizes some of the techniques used to implement an SMSM system. In an SMSM, fixed length words are organized into variable length records, and these records are packed into a file. The first word of the record, a label, can be associatively addressed to mark the record. Marked records can be output, erased, or a word or a collection of words can be inserted after the label of such records. Erased words are shifted to the bottom of memory as data words are packed upward, so that new records or extensions of old records can be inserted at the bottom of the file. In this system, although the file appears to be a single one dimensional array of words, it is actually stored on a number m of n word circular access memories, such as CCD's or tracks of a fixed head disc. Larger systems are implemented by increasing m. The access time for the entire system depends only on n. This architecture is self-managing in that no directories are kept, nor is software garbage collection or allocation necessary. The hardware replaces these functions. This appears to be a desirable direction for secondary memory architectures to develop, with special application to their use in computer networks. This paper discusses techniques for implementing an SMSM. These techniques were developed as part of the Context Addressed Segment Sequential Memory (CASSM) system. This paper therefore also describes that part of CASSM that, by itself, forms a useful SMSM. It is hoped that these techniques will be useful in the development of a new class of intelligent secondary memories to meet present and future needs of computing systems.

Space and time savings through large data base compression and dynamic restructuring

The conventional general-purpose data management system tends to make inefficient use of storage space. By reducing the physical size of the data, substantial savings are available in the area of storage cost. Reduction ratios of 4:1 and more are realizable. This also reduces the amount of I/O time required to physically transfer data between secondary and primary memories. Since I/O time tends to be the pacing factor when processing large data bases, this could produce a 4:1 or greater reduction in response time. Data compression experience with four large data bases is described. In some applications, only a small fraction of the data transferred in an individual I/O operation is relevant to the query being processed. If usage patterns are measured and data records and fields are rearranged so that those which are commonly referenced together are also physically stored together, then additional savings are available. Once the data base has been partitioned into clusters of commonly accessed data, further efficiencies can be obtained by choosing data structures, compression strategies, and storage devices that are optimal for the recent usage pattern observed on that cluster.