使用TPS62200作为OMAP1510的动态电压缩放器

毫无疑问的,延长便携式电子产品之电池使用寿命将有助于该产品的销售。对微处理器而言,降低内部时脉频率或降低核心电压均有助于降低其功率消耗。动态电压缩放(Dynamicvoltage scaling, DVS)技术常用来降低核心电压以降低功率消耗。本文将说明如何使用TPS62200降压型转换器来实现动态电压缩放技术并作为OMAP1510处理器之电源。下式说明了使用TI-DSP核心之微处理器的功率消耗计算方式:PC ～ (VC)2 × f其中PC代表核心功率消耗,VC为核心电压,f则为核心时脉频率。OMAP1510处理器具有两种操作模式:AWAKE(唤醒)模式以及低功耗的DE…     

Effects of preliminary perceptual output on neuronal activity of the primary motor cortex.

Observations of single neurons in the primary motor cortex of 1 monkey provided evidence that preliminary perceptual information reaches the motor system before perceptual analysis is complete. Neurons were recorded during a task in which 1 stimulus was assigned to a wrist flexion response and another was assigned to wrist extension. Two stimuli were assigned to a no-go response; each was visually similar to either the flexion or the extension stimulus. When a no-go stimulus was presented, neurons responded with weaker versions of the discharge patterns exhibited to the visually similar stimulus requiring a movement, suggesting that neurons receive partial perceptual information favoring that movement. Functionally separate neuronal populations were identified, and differences in the activations of these provide evidence about the functional effects of preliminary perceptual output on movement control processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation in pigeons (Columba livia)?

Previous research has shown pigeons to be insensitive to the orientation of visual test stimuli both for response latency and for discrimination ratio. Discrimination of stimulus orientation has been more difficult to learn than discrimination of small arbitrary differences between stimuli. This has suggested that the visual processing of pigeons is orientation invariant, which would obviate the need for mental rotation such as is often observed in studies with human subjects. Contrary to previous findings, the current experiment obtained linear effects of orientation on response latency and discrimination ratio, with a go/no-go procedure. Pigeons (Columbia livia) first learned to discriminate among line drawings of similar objects and then were tested with rotated versions of the drawings. The pattern of data is similar to that found in studies of human recognition of rotated objects. One speculative explanation of this finding is the mental rotation of stimuli by pigeons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

工业标准Mezzanine模块

典型的CompactPCI系统和VME系统的I/O扩展是通过使用各种规格的板卡来实现,如选用CompactPCI或VME类型的板卡来实现这一简单功能显得大材小用且得不偿失,简单的I/O功能需要一种更低成本和更小规格尺寸板卡的标准。这种对Mezzanine标准的需求被业界所认可,2001年夏,IEEE颁布了P1386和P1386.1标准。这些标准又进一步被PICMG和VITA提升来满足电信和高吞吐量的需求。尽管这些中介承载模块是针对CompactPCI和VME设计,但是它们可被用在任何规格板卡上,前提是提供标准的机械、电气、信号要求。PMC标准是两个IEEE标准的集合,IE…     

Category effects in temporal visual search.

When subjects identify a target during rapid serial visual presentation (RSVP), they show a reduced ability to detect a subsequent probe stimulus relative to when they ignore the target. The present study demonstrated an effect of target/probe categorical relation upon this probe detection deficit (attentional blink). Experiment 1 used letters for both target and probe, replicating the general methods and results of Raymond, Shapiro, and Arnell (1992). Experiment 2 varied target/probe categorical relation via instructional set: The target was referred to as the letter 'oh', whereas for other subjects it was referred to as the number 'zero.' Treating O as a number attenuated the probe detection deficit. This different-category attenuation was confirmed in Experiment 3 where the target was a letter and the probe was a number. The observed category effect suggests that the probe detection deficit in RSVP may map a time course from spreading intra-category inhibition following temporal target selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erosion of copper single crystals under conditions of 90° impact

High purity copper single crystals were eroded parallel to [111] at 90° to the surface with glass spheres 70 μm in diameter travelling at a velocity of 122 m s^?1. Detailed scanning electron microscopy of eroded surfaces together with transmission electron microscopy of both erosion debris and near-surface layers of the target was performed. It was observed that a hilland-valley surface topology developed ; this has not been reported previously and gave rise to a local low angle cutting component of erosion at 90°. Direct evidence was obtained of a transient heating effect from the particle impact as well as the formation of subsurface voids in heavily deformed regions. In addition it was shown that subsurface cracking produced a flaking mechanism of material loss.     

An Efficient Procedure for Implementing a Dual Simplex Network Flow Algorithm

This paper shows that for linear programming formulations of network flow problems, the nonzero components of rows of the basis inverse are identical. A simple algorithm for identifying these nonzero components is given along with a suggested data structure for implementation. The algorithm requires only one bit of storage for each node plus one additional bit. Finally we indicate how these ideas may be used in the development of a dual simplex code for network flow problems.     

Diet, alcohol, and physical activity as a function of smoking status in middle-aged women.

Diet, alcohol intake, and leisure-time physical activity were compared cross-sectionally in middle-aged female smokers, ex-smokers, and never smokers and were reassessed approximately 3 yrs later. At initial contact, there were no group differences in total caloric intake and very few differences in nutrient intake, but alcohol intake of current smokers and ex-smokers was at least 50% greater than that of never smokers, and current smokers reported less physical activity than did ex-smokers and never smokers. Prospective findings were similar: Compared with continuing smokers, ex-smokers did not change their dietary and alcohol intake but significantly increased physical activity. Thus, some adverse behaviors associated with smoking (e.g., alcohol intake) may be due to self-selection to history of smoking, whereas other behaviors (e.g., reduced physical activity) may be directly related to smoking itself. (PsycINFO Database Record (c) 2010 APA, all rights reserved)