Recurrent infomax generates cell assemblies, neuronal avalanches, and simple cell-like selectivity

Recently multineuronal recording has allowed us to observe patterned firings, synchronization, oscillation, and global state transitions in the recurrent networks of central nervous systems. We propose a learning algorithm based on the process of information maximization in a recurrent network, which we call recurrent infomax (RI). RI maximizes information retention and thereby minimizes information loss through time in a network. We find that feeding in external inputs consisting of information obtained from photographs of natural scenes into an RI-based model of a recurrent network results in the appearance of Gabor-like selectivity quite similar to that existing in simple cells of the primary visual cortex. We find that without external input, this network exhibits cell assembly-like and synfire chain-like spontaneous activity as well as a critical neuronal avalanche. In addition, we find that RI embeds externally input temporal firing patterns to the network so that it spontaneously reproduces these patterns after learning. RI provides a simple framework to explain a wide range of phenomena observed in in vivo and in vitro neuronal networks, and it will provide a novel understanding of experimental results for multineuronal activity and plasticity from an information-theoretic point of view.     

Multi-contact vertical ladder climbing with an HRP-2 humanoid

We describe the research and the integration methods we developed to make the HRP-2 humanoid robot climb vertical industrial-norm ladders. We use our multi-contact planner and multi-objective closed-loop control formulated as a QP (quadratic program). First, a set of contacts to climb the ladder is planned off-line (automatically or by the user). These contacts are provided as an input for a finite state machine. The latter builds supplementary tasks that account for geometric uncertainties and specific grasps procedures to be added to the QP controller. The latter provides instant desired states in terms of joint accelerations and contact forces to be tracked by the embedded low-level motor controllers. Our trials revealed that hardware changes are necessary, and parts of software must be made more robust. Yet, we confirmed that HRP-2 has the kinematic and power capabilities to climb real industrial ladders, such as those found in nuclear power plants and large scale manufacturing factories (e.g. aircraft, shipyard) and construction sites.     

Object detection based on a robust and accurate statistical multi-point-pair model

In this paper, we propose a robust and accurate background model, called grayscale arranging pairs (GAP). The model is based on the statistical reach feature (SRF), which is defined as a set of statistical pair-wise features. Using the GAP model, moving objects are successfully detected under a variety of complex environmental conditions. The main concept of the proposed method is the use of multiple point pairs that exhibit a stable statistical intensity relationship as a background model. The intensity difference between pixels of the pair is much more stable than the intensity of a single pixel, especially in varying environments. Our proposed method focuses more on the history of global spatial correlations between pixels than on the history of any given pixel or local spatial correlations. Furthermore, we clarify how to reduce the GAP modeling time and present experimental results comparing GAP with existing object detection methods, demonstrating that superior object detection with higher precision and recall rates is achieved by GAP.     

固井质量综合评价方法探讨

介绍并分析了目前固井质量评价中存在的主要问题,探讨了客观评价固井质量的方法。目前国内大部分油田采用声幅测井(CBL)评价固井质量,虽然声波/变密度测井(VDL)技术也正在作为基本的固井评价手段加以推广和应用,但是仍显不足,比如受微环隙、快速地层等因素的影响,测井资料易出现多解,常造成对固井质量的误判。本文着重针对以上两个因素的影响,介绍了应用多种测井方法组合的综合评价方法,并通过实例证明,得到了较好的效果。     

关于Ehrlich迭代法的一种推广

讨论Ehrlich迭代法的一种推广形式,给出收敛性定理及其简洁证明,并比较它和Newton迭代法的计算效率,得出当多项式的根全为单根时若多项式次数不低于4,则Ehrlich迭代法的效率高于Newton迭代法;当多项式的根不全为单根时,则Ehrlich迭代法的效率总高于Newton迭代法。     

Dependence of self-heating effects on operation conditions and device structures for polycrystalline silicon TFTs

Self-heating, a degradation mechanism of n-channel poly-Si thin-film transistors (TFTs) due to bias stress, has been investigated. The aim of this work is to study this effect in depth to be able to propose a device structure designed to reduce it. The variation of the threshold voltage (V/sub t/) shift with the stress-pulsewidth is related to the temperature rise due to the self-heating effect that depends on the stress-pulsewidth. Electron trapping in the oxide caused by the bias stress is considered to be enhanced by the TFT temperature rise owing to the self-heating. We show that copper-film-based TFTs, which have a substrate made of an extremely thin glass layer and a copper film exhibit much reduced self-heating and thus a decrease of V/sub t/ shift caused by the bias stress. These observations are interpreted using numerical simulations to estimate the temperature rise in the poly-Si channel region due to Joule heating.     

加速我国电器制造业数字化的策略

介绍了制造技术发展趋势以及如何用现代制造技术改造传统的电器制造业,其重点是企业信息化和制造工艺现代化.分析了目前信息化存在的重要问题,提出了企业制造业实现信息化的具体内容和步骤,包括实现数字化设计、生产、装备和管理技术的开发和应用.     

实验室认可、计量认证扩项时环境监测方法的确认途径

叙述了实验室认可和计量认证扩项时环境监测方法确认的一般途径,以及方法检出限、测量过程正确度、过程能力评定的一般步骤,在新检测方法开发评价方面也有运用前景.     

战略模拟中群决策方法管理平台的设计与实现

在综合集成的战略决策模拟环境中，多人研讨是主要的工作方式，利用多个领域的专家们的经验和智慧来对战略问题做出定性定量结合的判断。该文在分析典型群决策过程的基础上，分析和提出了战略决策研讨与模拟环境SDS2002中的群决策方法管理平台的服务机制，并给出了基于Bxchange 2000 Server的实现方案。     

Role of number of consecutive voltage zero-crossings in propagation of water trees in polyethylene

Effects of superposition of a low-frequency (0.1 to 50 Hz) voltage and a high-frequency 2 kHz voltage on the growth of water trees in polyethylene are examined. It has become clear that both the number of total voltage zero-crossings during the whole voltage application period and the number of consecutive voltage zero-crossings in the instant of the polarity reversal of the low-frequency voltage play important roles in the length and shape of water trees. Namely, the water tree length becomes longer as the number of total zero-crossings increases. Furthermore, among the voltages with the same number of total zero-crossings, the length becomes even longer with a prolonged shape in the direction of electric field as the number of consecutive zero-crossings increases. Effects of superposition of a high-frequency voltage onto a dc voltage are also examined. In this case, the dc voltage seems not to have any influence to the tree growth. By assuming the presence of space charge around the water-tree tip, the effective zero-crossings become only sensitive to the high-frequency component. Therefore, this result also indicates that the number of voltage reversals at the tree tip plays a crucial role in the growth of water trees.