A low complexity hardware architecture for motion estimation

This paper tackles the problem of accelerating motion estimation for video processing. A novel architecture using binary data is proposed, which attempts to reduce power consumption. The solution exploits redundant operations in the sum of absolute differences (SAD) calculation, by a mechanism known as early termination. Further data redundancies are exploited by using a run length coding addressing scheme, where access to pixels which do not contribute to the final SAD value is minimised. By using these two techniques operations and memory accesses are reduced by 93.29% and 69.17% respectively relative to a systolic array implementation

Energy-efficient acceleration of MPEG-4 compression tools

We propose novel hardware accelerator architectures for the most computationally demanding algorithms of the MPEG-4 video compression standard-motion estimation, binary motion estimation (for shape coding), and the forward/inverse discrete cosine transforms (incorporating shape adaptive modes). These accelerators have been designed using general low-energy design philosophies at the algorithmic/architectural abstraction levels. The themes of these philosophies are avoiding waste and trading area/performance for power and energy gains. Each core has been synthesised targeting TSMC 0.09 μm TCBN90LP technology, and the experimental results presented in this paper show that the proposed cores improve upon the prior art

Efficient hardware architectures for MPEG-4 core profile

Efficient hardware acceleration architectures are proposed for the most demandingMPEG-4 core profile algorithms, namely; texture motion estimation (TME), binary motion estimation (BME)and the shape adaptive discrete cosine transform (SA-DCT). The proposed ME designs may also be used for H.264, since both architectures can handle variable block sizes. Both ME architectures employ early termination techniques that reduce latency and save needless memory accesses and power consumption. They also use a pixel subsampling technique to facilitate parallelism, while balancing the computational load. The BME datapath also saves operations by using Run Length Coded (RLC) pixel addressing. The SA-DCT module has a re-configuring multiplier-less serial datapath using adders and multiplexers only to improve area and power. The SA-DCT packing steps are done using a minimal switching addressing scheme with guarded evaluation. All three modules have been synthesised targeting the WildCard-II FPGA benchmarking platform adopted by the MPEG-4 Part9 reference hardware group

Fraction-variant beam orientation optimization for non-coplanar IMRT

Conventional beam orientation optimization (BOO) algorithms for IMRT assume that the same set of beam angles is used for all treatment fractions. In this paper we present a BOO formulation based on group sparsity that simultaneously optimizes non-coplanar beam angles for all fractions, yielding a fraction-variant (FV) treatment plan. Beam angles are selected by solving a multi-fraction FMO problem involving 500-700 candidate beams per fraction, with an additional group sparsity term that encourages most candidate beams to be inactive. The optimization problem is solved using the Fast Iterative Shrinkage-Thresholding Algorithm. Our FV BOO algorithm is used to create non-coplanar, five-fraction treatment plans for prostate and lung cases, as well as a non-coplanar 30-fraction plan for a head and neck case. A homogeneous PTV dose coverage is maintained in all fractions. The treatment plans are compared with fraction-invariant plans that use a fixed set of beam angles for all fractions. The FV plans reduced mean and max OAR dose on average by 3.3% and 3.7% of the prescription dose, respectively. Notably, mean OAR dose was reduced by 14.3% of prescription dose (rectum), 11.6% (penile bulb), 10.7% (seminal vesicle), 5.5% (right femur), 3.5% (bladder), 4.0% (normal left lung), 15.5% (cochleas), and 5.2% (chiasm). Max OAR dose was reduced by 14.9% of prescription dose (right femur), 8.2% (penile bulb), 12.7% (prox. bronchus), 4.1% (normal left lung), 15.2% (cochleas), 10.1% (orbits), 9.1% (chiasm), 8.7% (brainstem), and 7.1% (parotids). Meanwhile, PTV homogeneity defined as D95/D5 improved from .95 to .98 (prostate case) and from .94 to .97 (lung case), and remained constant for the head and neck case. Moreover, the FV plans are dosimetrically similar to conventional plans that use twice as many beams per fraction. Thus, FV BOO offers the potential to reduce delivery time for non-coplanar IMRT

Origins of choice-related activity in mouse somatosensory cortex.

During perceptual decisions about faint or ambiguous sensory stimuli, even identical stimuli can produce different choices. Spike trains from sensory cortex neurons can predict trial-to-trial variability in choice. Choice-related spiking is widely studied as a way to link cortical activity to perception, but its origins remain unclear. Using imaging and electrophysiology, we found that mouse primary somatosensory cortex neurons showed robust choice-related activity during a tactile detection task. Spike trains from primary mechanoreceptive neurons did not predict choices about identical stimuli. Spike trains from thalamic relay neurons showed highly transient, weak choice-related activity. Intracellular recordings in cortex revealed a prolonged choice-related depolarization in most neurons that was not accounted for by feed-forward thalamic input. Top-down axons projecting from secondary to primary somatosensory cortex signaled choice. An intracellular measure of stimulus sensitivity determined which neurons converted choice-related depolarization into spiking. Our results reveal how choice-related spiking emerges across neural circuits and within single neurons

Sex signs: transsexuality, autobiography, and the languages of sexual difference in the United Kingdom and United States of America, 1950-2000

This dissertation explores the relationship between transsexuality, autobiography and ideas of sexual difference in the United Kingdom and the United States of America between the years 1950 and 2000. This dissertation argues that rather than viewing sex and gender in hierarchic fashion, transsexual autobiography allows us to see their relationship as mutually legitimating. Both biological sex and psychological gender acted as historically contingent ‘sex signs’ which worked to show the autobiographer as man or woman, despite having been born in the opposite sex. I argue that far from biology dictating gender, or gender defining sex, both were used equally and strategically by transsexuals in order to fluently speak a language of sexual difference which their ‘audiences’ – be they medical professionals, legal scholars, newspaper journalists, or close friends and family members – could understand. This fluency permitted belief in them as the men or women they knew themselves to be. At some times, and in some company, genital sex signs were the most appropriate way of signifying sexual difference, whist in a different place and with different people, certain gender traits were more useful. Always, though, was the transsexual’s signification of him- or her-self as man or woman delimited by public discourses of sexual difference which impacted upon ‘non-transsexuals’ also. In closely reading transsexual autobiographies we are better able to see the construction, and naturalisation, of sexual difference in the second half of the twentieth century. By looking both at the strategic uses of transsexual autobiographies and the wider public reactions to such life stories (and the individuals who tell them), this dissertation shows how the languages of sexual difference, of ‘man’ and ‘woman’ were in a constant state of flux during the period in question