Overview of emerging nonvolatile memory technologies

Nonvolatile memory technologies in Si-based electronics date back to the 1990s. Ferroelectric field-effect transistor (FeFET) was one of the most promising devices replacing the conventional Flash memory facing physical scaling limitations at those times. A variant of charge storage memory referred to as Flash memory is widely used in consumer electronic products such as cell phones and music players while NAND Flash-based solid-state disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. The integration limit of Flash memories is approaching, and many new types of memory to replace conventional Flash memories have been proposed. Emerging memory technologies promise new memories to store more data at less cost than the expensive-to-build silicon chips used by popular consumer gadgets including digital cameras, cell phones and portable music players. They are being investigated and lead to the future as potential alternatives to existing memories in future computing systems. Emerging nonvolatile memory technologies such as magnetic random-access memory (MRAM), spin-transfer torque random-access memory (STT-RAM), ferroelectric random-access memory (FeRAM), phase-change memory (PCM), and resistive random-access memory (RRAM) combine the speed of static random-access memory (SRAM), the density of dynamic random-access memory (DRAM), and the nonvolatility of Flash memory and so become very attractive as another possibility for future memory hierarchies. Many other new classes of emerging memory technologies such as transparent and plastic, three-dimensional (3-D), and quantum dot memory technologies have also gained tremendous popularity in recent years. Subsequently, not an exaggeration to say that computer memory could soon earn the ultimate commercial validation for commercial scale-up and production the cheap plastic knockoff. Therefore, this review is devoted to the rapidly developing new class of memory technologies and scaling of scientific procedures based on an investigation of recent progress in advanced Flash memory devices.     

Polysiloxanes for optoelectronic applications

During the past few years, polysiloxanes have been extensively researched on optimizing the physical and electronic properties of organic polymer semiconductors. Polysiloxanes display their advantages including good solubility in common organic solvents, good film-forming ability, fair adhesion to various substrates and excellent resistance to thermal, chemical and irradiation degradations. In this review, we focus on the fundamental design and synthesis strategies of bonding polysiloxanes with organoelectronic groups. The characterization of polysiloxanes will be briefly introduced. Specifically, we summarize the recent advances of the utilization of polysiloxanes as organic light-emitting diodes (OLEDs), solar cells, electrical memories and liquid crystalline materials. Finally, several perspectives related to polysiloxanes materials for organoelectronic applications are proposed based on the reported progress and our own opinion.     

B-hist: Entity-centric search over personal web browsing history

Web Search is increasingly entity centric; as a large fraction of common queries target specific entities, search results get progressively augmented with semi-structured and multimedia information about those entities. However, search over personal web browsing history still revolves around keyword-search mostly. In this paper, we present a novel approach to answer queries over web browsing logs that takes into account entities appearing in the web pages, user activities, as well as temporal information. Our system, B-hist, aims at providing web users with an effective tool for searching and accessing information they previously looked up on the web by supporting multiple ways of filtering results using clustering and entity-centric search. In the following, we present our system and motivate our User Interface (UI) design choices by detailing the results of a survey on web browsing and history search. In addition, we present an empirical evaluation of our entity-based approach used to cluster web pages.     

BE-TANOS: Feasibility and technology limitations

The aim of this work is to investigate the physical mechanisms behind the write/erase and retention performances of band gap engineering (BE) layers used as tunnel oxide in charge trap memory stack. The investigation of the BE layers alone will be completed with the analyses of its integration within a TANOS (TaN/Alumina/Nitride/Oxide/Silicon) stack, pointing out the correlation between electrical performance and reliability limits.Good write/erase/retention performances can be achieved with BE tunnel oxide by using silicon nitride layer integrated in SiO₂-Si₃N₄-SiO₂ stack, as long as all different mechanisms are taken into account in optimizing stack composition: hole injection which improves erase efficiency, charge trapping and de-trapping from the thin silicon nitride which causes program instabilities and initial charge loss which does not significantly impact long term retention. All these phenomena make very crucial the BE tunnel process control and difficult its use for multi-level application.     

Adaptive particle swarm optimization for CNN associative memories design

In this paper particle swarm optimization is used to implement a synthesis procedure for cellular neural networks autoassociative memories. The use of this optimization technique allows a global search for computing the model parameters that identify designed memories, providing a synthesis procedure that takes into account the robustness of the solution. In particular, the design parameters can be modified during the convergence in order to guarantee minimum recall performances of the network in terms of robustness to noise overlapped to input patterns. Numerical results confirm the good performances of the designed networks when patterns are affected by different kinds of noise.     

Repressed memories: Avoiding the obvious.

Sorting out the distinctions between reality and fantasy in terms of apparently recovered memories and reconstructions is at least as puzzling as sorting out current realities. In responding to C. B. Brenneis's (see records 2007-10660-001 and 2001-07368-001) challenge to the existence of the phenomena of repression and of recovered or reconstructed memories, the authors point out the data from the Recovered Memory Archive web site, the data from World War I and World War II battlefield neuroses, as well as the clinical observations of psychoanalysts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

留住并延续城市记忆——“印象系列”的扎根理论应用初探

城市记忆是城市发展、变迁过程中留下的印记,它记录了城市的点点滴滴,是人们对一所城市最直观的印象表达。不同的城市有自己不同的印象,城市需要沿着记忆的长绳,去拾掇、发掘属于自己的特有元素符号,才能塑造出属于自己的独一无二。文章首先以张艺谋的＂印象系列＂作品为引子,提出城市文化继承与延用中的断层现象,再通过对《城市的印象》一书中的五大塑造理论因素进行初步探索,并结合谢菲尔德、上海这两座城市的塑造实例,最后总结出绵延城市记忆、塑造个性化城市的方法。     

基于双口RAM的并行数据通信方法研究

介绍了在微机间实现并行数据通信的两种通信方案，给出了两种针对不同传输要求的并行数据通信的软硬件实现原理和方法。