4921719
Hardware-efficient propagate partial sad architecture for variable block size motion estimation in H.264/AVC
One hardware efficient and high speed architecture for variableblock size motion estimation in H.264 is presented in this paper. Through compressing the propagated data and optimizing theprocessing element and adder tree circuits in pipeline, this architecture gets more hardware efficient datapath logic. Compared with the original Propagate Partial SAD structure, 12.1% hardware cost can be saved. With TSMC 0.18μm CMOS 1P6M standard celllibrary, the maximum clock speed of this design is 227MHz in worstwork conditions (1.62V, 125°C). With the 48x32 search range, the maximum throughput of our design is 147786 MB/S, which can be used in the real-time encoding of VGA resolution frame with 4 reference frames at 30Hz.
9240638
An Irregular Search Window Reuse Scheme for Motion Estimation in MPEG-2 to H.264 Transcoding
Motion estimation (ME) is a computation-intensive operation in video coding system. In MPEG-2 to H.264 transcoding, motion vector (MV) from MPEG-2 reused as search center in H.264 encoder is a simple but effective technique to simplify ME procedure. However directly introducing MPEG-2 MV will bring irregular overlapping between search windows of successive macroblocks (MB) which invalidates the data reuse scheme in hardware design of ME module. In this paper, the authors propose a search window reuse scheme for transcoding in HDTV application. By utilizing the similarity between neighboring MVs, overlapping of search windows between successive MBs can be regularized. Experiment results show that our method achieve average 93.1% search window reuse rate in HDTV sequence with almost no video quality degradation. And the bandwidth can be reduced to 92.5 Mbytes/s based on theoretical calculation which is only 40.6% of that without this scheme.
7056002
A VLSI array processing oriented fast fourier transform algorithm and hardware implementation
Many parallel Fast Fourier Transform (FFT) algorithms adopt multiple stages architecture to increase performance. However, data permutation between stages consumes volume memory and processing time. An FFT array processing mapping algorithm is proposed in this paper to overcome this demerit. In this algorithm, arbitrary 2k butterfly units (BUs) could be scheduled to work in parallel on n=22 data (k=0, 1,..., s-1). Because no inter stage data transfer is required, memory consumption is reduced to 1/3 of the original algorithm. Moreover, with the increasing of BUs, not only does throughput increase linearly, system latency also decreases linearly. This array processing orientated architecture provides flexible tradeoff between hardware cost and system performance. An 18-bit word-length 1024-point FFT architecture with 4 BUs is given to demonstrate this mapping algorithm. The design is implemented with TSMC 0.18μm CMOS technology. The core area is 2.99x1.12mm 2 and clock frequency is 326MHz in typical condition (1.8V, 25°C). This processor could complete 1024 FFT calculation in 7.839μs.
7172331
Enhanced Strict Multilevel Successive Elimination Algorithm for Fast Motion Estimation
This paper presents an enhanced strict multilevel successive elimination algorithm (EMSEA) for fast block-matching motion estimation, which is based on the previous strict multilevel successive elimination algorithm (SMSEA) (Song et al., 2006). Different to the SMSEA algorithm with fixed parameters, in EMSEA algorithm, the whole search area is divided into two regions and each region has its own parameters. Therefore, the computation complexity of SMSEA algorithm can be further decreased. Experiments show that the proposed EMSEA algorithm can reduce 16.2% of the SMSEA computation and maintain almost the same image quality, which is better than the TSS and DS algorithms.
16829828
Algorithms for Imperfect Phylogeny Haplotyping (IPPH) with a Single Homoplasy or Recombination Event
The haplotype inference (HI) problem is the problem of inferring 2n haplotype pairs from n observed genotype vectors. This is a key problem that arises in studying genetic variation in populations, for example in the ongoing HapMap project [5]. In order to have a hope of finding the haplotypes that actually generated the observed genotypes, we must use some (implicit or explicit) genetic model of the evolution of the underlying haplotypes. The Perfect Phylogeny Haplotyping (PPH) model was introduced in 2002 [9] to reflect the “neutral coalescent” or “perfect phylogeny” model of haplotype evolution. The PPH problem (which can be solved in polynomial time) is to determine whether there is an HI solution where the inferred haplotypes can be derived on a perfect phylogeny (tree). 
 
Since the introduction of the PPH model, several extensions and modifications of the PPH model have been examined. The most important modification, to model biological reality better, is to allow a limited number of biological events that violate the perfect phylogeny model. This was accomplished implicitly in [7,12] with the inclusion of several heuristics into an algorithm for the PPH problem [8]. Those heuristics are invoked when the genotype data cannot be explained with haplotypes that fit the perfect phylogeny model. In this paper, we address the issue explicitly, by allowing one recombination or homoplasy event in the model of haplotype evolution. We formalize the problems and provide a polynomial time solution for one problem, using an additional, empirically-supported assumption. We present a related framework for the second problem which gives a practical algorithm. We believe the second problem can be solved in polynomial time.
2185149
Monocular perception of biological motion-detection and labeling
Computer perception of biological motion is key to developing convenient and powerful human-computer interfaces. Successful body tracking algorithms have been developed; however initialization is done by hand. We propose a method for detecting a moving human body and for labeling its parts automatically. It is based on maximizing the joint probability density function (PDF) of the position and velocity of the body parts. The PDF is estimated from training data. Dynamic programming is used for calculating efficiently the best global labeling on an approximation of the PDF. The computational cost is on the order of N/sup 4/ where N is the number of features detected. We explore the performance of our method with experiments carried on a variety of periodic and non-periodic body motions viewed monocularly for a total of approximately 30,000 frames. Point-markers were strapped to the joints of the subject for facilitating image analysis. We find an average of 2.3% labeling error; the experiments also suggest a high degree of viewpoint-invariance.
1562361
Learning probabilistic structure for human motion detection
Decomposable triangulated graphs have been shown to be efficient and effective for modeling the probabilistic spatio-temporal structure of brief stretches of human motion. In previous work such model structure was handcrafted by expert human observers and labeled data were needed for parameter learning. We present a method to build automatically the structure of the decomposable triangulated graph from unlabeled data. It is based on maximum-likelihood. Taking the labeling of the data as hidden variables, a variant of the EM algorithm can be applied. A greedy algorithm is developed to search for the optimal structure of the decomposable model based on the (conditional) differential entropy of variables. Our algorithm is demonstrated by learning models of human motion completely automatically from unlabeled real image sequences with clutter and occlusion. Experiments on both motion captured data and grayscale image sequences show that the resulting models perform better than the hand-constructed models.
6362823
Assigning textual names to sets of geographic coordinates
NameSet is a system that translates a set of geographic coordinates into a textual name based on the geographic regions where the coordinates occur. One possible application of NameSet is to concisely present the geographical scope of a set of geo-referenced observations to a human user. Another application is to generate text to depict a set of coordinates that appear on a web site -- text that could later be used for information retrieval applications. NameSet's computation is based on a simple algorithm, using off-the-shelf and web-based data sources. The system was proven effective in an application that automatically organizes and names sets of geo-referenced digital photographs.
16612931
Efficient computation of close lower and upper bounds on the minimum number of recombinations in biological sequence evolution
MOTIVATION
We are interested in studying the evolution of DNA single nucleotide polymorphism sequences which have undergone (meiotic) recombination. For a given set of sequences, computing the minimum number of recombinations needed to explain the sequences (with one mutation per site) is a standard question of interest, but it has been shown to be NP-hard, and previous algorithms that compute it exactly work either only on very small datasets or on problems with special structure.


RESULTS
In this paper, we present efficient, practical methods for computing both upper and lower bounds on the minimum number of needed recombinations, and for constructing evolutionary histories that explain the input sequences. We study in detail the efficiency and accuracy of these algorithms on both simulated and real data sets. The algorithms produce very close upper and lower bounds, which match exactly in a surprisingly wide range of data. Thus, with the use of new, very effective lower bounding methods and an efficient algorithm for computing upper bounds, this approach allows the efficient, exact computation of the minimum number of needed recombinations, with high frequency in a large range of data. When upper and lower bounds match, evolutionary histories found by our algorithm correspond to the most parsimonious histories.


AVAILABILITY
HapBound and SHRUB, programs implementing the new algorithms discussed in this paper, are available at http://wwwcsif.cs.ucdavis.edu/~gusfield/lu.html