Flow Analytic Type System for Array Bound Checks

AbstractIt is widely recognized that formulating program analysis by a type system is a promising approach because of its clarity and rigidity. However, there remains much to be done for applying them to practical use. One of the problems is that it is not trivial what kind of type systems is appropriate for low level languages. To solve the problem, the type systems must be closely related to data flow analysis because it has been the major method for analyzing low level languages. In this paper, taking array bound checks as an example, first we propose a framework for type systems for low level languages derived from data flow analysis. Second, we propose a type system for analyzing programs as a network of blocks (especially loops), dealing with SSA form and induction variables

半直積構造を持つ群に対するGray符号の構成と位数16の群への応用

筑波大学 (University of Tsukuba)201

Parametrically Excited Vibration with External Constant Load and Damping

The vibrations of gears can be expressed by differential equations of parametrically excited vibrations. In this paper, the stabilities of parametrically excited vibrations of the MeiBner and Mathieu types (the former expresses the torsional vibrations of spur gears and the latter expresses those of helical gears) and their vibrational characteristics in the stable region are theoretically investigated. Through this investigation, the effects of the helix angle and the damping factor on the vibrations of gears are made clear. The vibrations of helical gears are smaller than those of spur gears. And the vibrations of helical gears with a large helix angle are smaller than those with a small helix angle. When the damping factor ζ increases, the unstable region decreases, and the peak levels of vibrations decrease remarkably, although the amplitude at the other region does not decrease. When we drive a pair of gears at a speed whose meshing frequency is two times faster than the natural frequency of the gearing system, the gears with a small damping have a very large vibration, but the gears with a large damping rotate smoothly

Attentional disengagement biases in social anxiety disorder

Social anxiety disorder (SAD) is a mental disorder characterized by significant fear and anxiety about social situations that may attract attention from others. Selective attention in social anxiety is characterized by a preferential attention to external threatening stimuli. The aim of this study is to test the influence of social anxiety on attentional disengagement bias. Attentional biases are phenomena where attention preferentially targets threatening stimuli. Attention is hypothesized to consist of three processes: engagement, shifting, and disengagement. Previous studies have suggested that people with SAD have impaired attentional engagement with the threatening stimuli. However, recent studies have used the dot-probe task to measure the attentional biases to show that people with SAD have impaired attentional disengagement. However, the dot-probe task is not suitable for separately assessing attentional disengagement or engagement biases. Therefore, we used a gap/overlap task, which can measure attentional disengagement bias, in 16 university students from high and low SAD groups. Faces were used as stimuli for the gap/overlap task (i.e., angry/happy/neutral). The results showed no significant difference between the high and low SAD groups in their attentional disengagement bias. We discussed the possible causes of this discrepancy between the previous studies and the current study in the relationship between social anxiety and attentional disengagement bias

The Impact of Syllabic Numbers on Chinese Loanwords in Japanese and Korean

　This paper investigated the top 1000 most commonly used verbs and adjectives with Chinese-origin roots in either Japanese or Korean and demonstrated that there are very few verbs/adjectives with one-character (or monographemic) roots, whereas there are many verbs/adjectives with two-character (or digraphemic) roots (about 90% for each category in both languages). It explained the difference between verbs with mono- and digraphemic Chinese-origin roots by arguing that digraphemic verbal roots are nouns, while monographemic ones are not, based on findings from language contact, particularly borrowing, and Chinese linguistics: i.e., (i) nouns are much more borrowable than verbs, and (ii) monosyllabic verbs in general do not, while disyllabic ones do, have corresponding deverbal nouns in the source-language, Chinese. It further applied a test of separability and confirmed that those digraphemic roots are morphologically free, while the monographemic ones are bound. This conclusion supports the approach in which verbal nouns, most of which are Chinese-origin digraphemic roots, are nouns.　本論文は、中国語からの借用形態素からなる日本語および韓国語の動詞・形容（動）詞のうち、それぞれ最も高頻度の千語を選び、漢語語基の漢字数によりどのような比率の違いがあるかを検証し、2 漢字の語基が90％前後を占め、1 漢字の語基は非常に少数であることを示した。この違いに関して、本論文は、言語接触の知見から、名詞は最も借用語となりやすく、動詞は借用されにくいこと、また、中国語学の知見から、中国語の1 音節動詞は、ほとんどが対応する名詞を持たず、2 音節動詞は多数が対応する名詞を持つことを指摘し、2 漢字語基は名詞と見なされて日韓語に借用され、1 漢字は名詞と見なされず、ほとんど借用されなかったと説明する。また、これらの動詞の漢語語基が後続する動詞から分離可能かどうかを調べ、1 字の漢語語基は殆ど拘束形態素と見なされ、２字の漢語語基は殆ど全て自由形態素であることを示した。この結果は殆どが２字漢字からなる「動名詞」を名詞として扱う立場を支持するものである

Scaling of soaring seabirds and its implication for the maximum size of flying pterosaurs

The flight ability of animals is restricted by the scaling effects imposed by physical and physiological factors. In comparisons of the power available from muscle and the mechanical power required to fly, theoretical studies have predicted that the margin between the powers should decrease with body size and that flying animals have a maximum body size. However, predicting an absolute value of this upper limit has been difficult because wing morphology and flight styles vary among species. Albatrosses and petrels have long, narrow, aerodynamically efficient wings and are considered to be soaring birds. Here, using animal-borne accelerometers, we show that scaling analyses of wing-flapping frequencies in these seabirds indicate that the maximum size limit for soaring animals is a body mass of 41 kg and a wingspan of 5.1 m. Soaring seabirds were observed to have two modes of flapping frequencies: vigorous flapping during takeoff and sporadic flapping during cruising flight. In these species, high and low flapping frequencies were found to scale with body mass (_mass_ ^-0.30^ and _mass_ ^-0.18^) in a manner similar to the predictions from biomechanical flight models (_mass_ ^-1/3^ and _mass_ ^-1/6^). The scaling relationships predicted that animals larger than the limit will not be able to flap fast enough to stay aloft under unfavourable wind conditions. Our result therefore casts doubt on the flying ability of large, extinct pterosaurs. The largest extant soarer, the wandering albatross, weighs about 10 kg, which might be a pragmatic limit to maintain a safety margin for sustainable flight and to survive in a variable environment