Task Modeling by the Keywords Extracted from Manual Pages

A task modeling method using keywords related to the functions of commands for intelligent user interfaces is proposed. A task model is a description of functions and operations of the computer. The task model is described as the name of a task in our method. We define the name of a task as the minimal set of common keywords which definitely distinguish the task. For the name of a task, keywords indicating the concepts of each command are needed. Since the order of the number of the keywords is that of the number of the commands, it is much easier to implement this method than a procedural knowledge based one. We also propose a method to extract the keywords automatically from the manual pages, the on-line reference manuals for UNIX. Since almost every command is associated with manual pages, the task names can be easily updated when a new command is added to the system. To show the effectiveness of the task names and the keywords extracted from the manual pages, we direct our attention to users' command histories. We show the effectiveness of these keywords by showing the relationship between the tasks in the history and the task names through statistical analysis

Current-induced magnetization switching in MgO barrier magnetic tunnel junctions with CoFeB based synthetic ferrimagnetic free layers

We investigated the effect of using a synthetic ferrimagnetic (SyF) free layer in MgO-based magnetic tunnel junctions (MTJs) on current-induced magnetization switching (CIMS), particularly for application to spin-transfer torque random access memory (SPRAM). The employed SyF free layer had a Co40Fe40B20/ Ru/ Co40Fe40B20 and Co20Fe60B20/Ru/Co20Fe60B20 structures, and the MTJs(100x(150-300) nm^2) were annealed at 300oC. The use of SyF free layer resulted in low intrinsic critical current density (Jc0) without degrading the thermal-stability factor (E/kBT, where E, kB, and T are the energy potential, the Boltzmann constant, and temperature,respectively). When the two CoFeB layers of a strongly antiferromagnetically coupled SyF free layer had the same thickness, Jc0 was reduced to 2-4x10^6 A/cm^2. This low Jc0 may be due to the decreased effective volume under the large spin accumulation at the CoFeB/Ru. The E/kBT was over 60, resulting in a retention time of over ten years and suppression of the write current dispersion for SPRAM. The use of the SyF free layer also resulted in a bistable (parallel/antiparallel) magnetization configuration at zero field, enabling the realization of CIMS without the need to apply external fields to compensate for the offset field.Comment: 6 page

Layer thickness dependence of the current induced effective field vector in Ta|CoFeB|MgO

The role of current induced effective magnetic field in ultrathin magnetic heterostructures is increasingly gaining interest since it can provide efficient ways of manipulating magnetization electrically. Two effects, known as the Rashba spin orbit field and the spin Hall spin torque, have been reported to be responsible for the generation of the effective field. However, quantitative understanding of the effective field, including its direction with respect to the current flow, is lacking. Here we show vector measurements of the current induced effective field in Ta|CoFeB|MgO heterostructrures. The effective field shows significant dependence on the Ta and CoFeB layers' thickness. In particular, 1 nm thickness variation of the Ta layer can result in nearly two orders of magnitude difference in the effective field. Moreover, its sign changes when the Ta layer thickness is reduced, indicating that there are two competing effects that contribute to the effective field. The relative size of the effective field vector components, directed transverse and parallel to the current flow, varies as the Ta thickness is changed. Our results illustrate the profound characteristics of just a few atomic layer thick metals and their influence on magnetization dynamics

京都大学における遠隔講義システム

本稿では、平成10年2月に導入された京都大学の遠隔講義システムの目的・構成・運用計画について説明し、今後の研究計画について述べる。遠隔講義システムは、(1)京都大学内の13箇所のサテライト講義室にMPEG2エンコーダ/デコーダを設置しATMネットワークを利用して講義映像を伝送するシステムと、(2)ゼミ室レベルでも映像伝送ができるMotion-JPEGを用いた簡易遠隔講義・会議システムの2つのサブシステムから構成される。本稿ではこれらのシステムの概要を述べ、その比較を行う。また、今後の研究計画に関しては、音声による対話が可能な遠隔講義を補助する知的エージェントの開発、および講義の自動ハイパーメディア化について説明する。In this paper, we describe a distance learning system in Kyoto University. This distance learning system consits of two subsystems: (1) a distance lecture system composed of MPEG2 CODEC used in a large-scale ATM network, and (2) a distance meeting system composed of Motion-JPEG CODEC used with high-end PCs. We also explain several research plans for this distance learning system; i.e., (a) developing a support agent for this distance learning system using speech recognition technology, and (b) developing an auto archiver for lecture materials

Extracting Straight Lines by Sequential Fuzzy Clustering

In clustering line segments into a straight line, threshold-based methods such as hierarchical clustering are often used. The line segments comprising a straight line often get misaligned due to noise. Thresholdbased methods have difficulty clustering such line segments. A new cluster extraction method is proposed to cope with this problem. This method extracts fuzzy clusters one by one using matrix computation. We evaluated our clustering method using hand-written drawings and obtained promising results. 1 Introduction Extraction of lines from an image is an essential task in computer vision. Many authors have reported various algorithms for line extraction, such as Hough Transformation and gradientbased methods[2]. An effective approach to line extraction is by clustering line segments [5, 6]. Line segments are obtained by applying a line fitting process to the output of edge detection process. A line segment is a small geometric structure defined by two end points. In many cases, l..

Sequential Fuzzy Cluster Extraction and Its Robustness Against Noise

Partitional clustering methods such as C-Means classify all samples into clusters. Even a noise sample that is distant from any cluster is assigned to one of the clusters. Noise samples included in clusters bias the clustering result and tend to produce meaningless clusters. Our clustering method repeats to extract mutually close samples as a cluster and leave isolated noises unclustered. Thus, the produced clusters are less affected by noises than those of C-Means. Because clusters can be obtained analytically by our method, repeated trials to avoid local minima are not necessary. The method is shown to be effective for extracting straight lines from images in the experiments. Keywords: Cluster Extraction, Clustering, Eigenvalue Problem, Scale, Noise 1 Introduction The purpose of clustering is to find clusters from a set of samples, where a cluster is comprised of a number of similar samples grouped together[1]. In general settings, a sample i(i = 1; 1 1 1 ; n) is represented by a s..

Maximization of second-harmonic power using normal-cut nonlinear crystals in a high-enhancement external cavity

When an antireflection-coated normal-cut nonlinear crystal is used in an external cavity for the generation of high second-harmonic power, a small residual reflection at the crystal facets causes a round-trip loss and prevents the realization of a large fundamental enhancement. This problem is eliminated when the reflected beams at the crystal facets are subject to constructive interference. We demonstrate that the temperature tuning of a β-BaB2O4 crystal of at most 3 K is sufficient to realize constructive interference at any wavelength. We achieve an enhancement factor of 125, and a second-harmonic power of 125 mW is generated at 398 nm from a fundamental power of 390 mW

An fMRI study on auditory selective attention in diotic listening paradigm-463.25

Selective listening is an essential auditory process that enables one to attend to the speech of a certain speaker among a mixture of parallel conversations, a phenomenon known as the cocktail party effect. Early experimental psychology in this area has long employed a so-called dichotic listening paradigm, where the subjects were typically presented with a set of monotonic tones, distinct to each ear, and were instructed to identify a target tone. The experimental setting of such a paradigm is, however, conceptually far from that we experience in daily life. Here, we instead developed an experimental paradigm based father on actual human conversation, and thereby investigated neural network underpinning the selective listening function in more realistic auditory settings. Twenty healthy volunteers (mean age 24.9 years) participated in the following experimental session, during which their cerebral hemodynamic activities were recorded by functional magnetic resonance imaging (fMRI). In a single fMRI session, the subjects were presented with auditory stimuli in one of the three conditions: (1) a news story read by a target speaker (N condition), (2) two news stories read simultaneously but independently by the target and other speaker (i.e. distracter) of an incongruent sex (Si condition), and (3) the same as (2) but sex of the distracter being congruent (Sc condition). The duration of each condition was 20 s, and the stimuli were followed by a visual presentation of a word, for which the subjects were instructed to judge whether or not the word was present in the preceding story. This train of conditions was repeated six times, and the brain activities during the Si and Sc conditions were compared with that in the N condition. We found that (a) in both Si and Sc conditions, prominent activations were observed in bilateral superior and middle temporal gyri, (b) compared to the Si condition, the activations in the Sc condition were more widespread and observed also in left inferior and middle frontal gyri, and (c) among these regions, the activities in temporal areas were positively correlated with the performance of the word challenge. Collectively, these results suggest that bilateral temporal and left frontal lobes play a key role in selective listening encountered in daily life depending on the degree of attention.38th Annual Meeting of Society for Neuroscienc