自适应阈值图像二值化及形态学处理的FPGA实现

针对固定阈值法图像二值化不足以及二值化后图像存在严重干扰,传统DSP等处理器在高速图像处理中实时性差,提出了以FPGA/Nios II为处理器,运用改进的自适应阈值Sobel算法实现对图像的二值化,再进行形态学的处理。整个系统实现包括原始图像的采集、色彩格式转换、灰度处理、边缘检测以及运用中值滤波和加权平均法实现自适应阈值图像二值化,最后再运用形态学方法对二值化后图像做进一步处理,实现轮廓的更加有效的提取,并通过VGA接口实现显示。实验结果表明该系统检测效率高,速度快,稳定可靠。     

Detection of non-topological motifs in protein structures

We present an efficient technique for the comparison of proteinstructures. The algorithm uses a vector representation of thesecondary structure elements and searches for spatial configurationsof secondary structure elements in proteins. In such recurringprotein folds, the order of the secondary structure elementsin the protein chains is disregarded. The method is based onthe geometric hashing paradigm and implements approaches originatingin computer vision. It represents and matches the secondarystructure element vectors in a 3-D translation and rotationinvariant manner. The matching of a pair of proteins takes onaverage under 3 s on a Silicon Graphics Indigo2 workstation,allowing extensive all-against-all comparisons of the data setof non-redundant protein structures. Here we have carried outsuch a comparison for a data set of over 500 protein molecules.The detection of recurring topological and non-topological,secondary structure element order-independent protein foldsmay provide further insight into evolution. Moreover, as theserecurring folding units are likely to be conformationalHy favourable,the availability of a data set of such topological motifs canserve as a rich input for threading routines. Below, we describethis rapid technique and the results it has obtained. Whilesome of the obtained matches conserve the order of the secondarystructure elements, others are entirely order independent. Asan example, we focus on the results obtained for Che Y, a signaltransduction protein, and on the profilin-ß-actincomplex. The Che Y molecule is composed of a five-stranded,parallel ß-sheet flanked by five helices. Here weshow its similarity with the Escherichia coli elongation factor,with L-arabinose binding protein, with haloalkane dehalogenaseand with adenylate kinase. The profilin–ß-actincontains an antiparallel ß-pleated sheet with -helicaltermini. Its similarities to lipase, fructose disphosphataseand ß-lactamase are displayed.     

Effect of Congeneric Chemical Signals of Different Ages on Foraging Response and Food Choice in the Field by Golden Spiny Mice (Acomys russatus)

The common spiny mice Acomys dimidiatus and golden spiny mice Acomys russatus coexist in the extreme warm and dry parts of the Rift Valley in Israel. However, they are temporally segregated in that the former is nocturnal, whereas the latter is diurnal. Daily rhythms of physiological and behavioral variables in A. russatus responded to semiochemical signals released by A. dimidiatus (in the urine and feces). Both species feed upon the same food items but at different times of the 24-hr cycle. The main aim of the present study was to test under field conditions the foraging response of A. russatus to odors of different ages released by A. dimidiatus. Various feeding and behavioral variables were compared in three groups of A. russatus. The results show that fresh semiochemical signals released by A. dimidiatus decrease the feeding efficiency and increase the rate of smelling from a distance in A. russatus. These results support the idea that temporal segregation between the two coexisting species is at least partly through semiochemicals present in the urine and feces.     

Filling carbon nanotubes with particles

The filling of carbon nanotubes (CNTs) with fluorescent particles was studied experimentally and theoretically. The fluorescent signals emitted by the particles were visible through the walls of the nanotubes, and the particles inside the tubes were observable with an electron microscope. Taking advantage of the template-grown carbon nanotubes' transparency to fluorescent light, we measured the filling rate of the tubes with particles at room conditions. Liquids such as ethylene glycol, water, and ethylene glycol/water mixtures, laden with 50 nm diameter fluorescent particles, were brought into contact with 500 nm diameter CNTs. The liquid and the particles' transport were observed, respectively, with optical and fluorescence microscopy. The CNTs were filled controllably with particles by the complementary action of capillary forces and the evaporation of the liquid. The experimental results were compared and favorably agreed with theoretical predictions. This is the first report on fluorescence studies of particle transport in carbon nanotubes.     

Temporal segregation in coexisting spiny mice (genus Acomys): role of photoperiod and heterospecific odor

The distal long arm of chromosome 10 harbors genes of biomedical interest such as MXI1, a putative tumor suppressor gene, and those encoding the adrenergic receptors alpha2A (ADRA2A) and beta1 (ADRB1). As part of a physical and genetic study of this genomic region, we constructed a 1.5-Mb YAC contig mapping to 10q25 that contains MXI1 and ADRA2A as well as a number of STSs. Rare cutting restriction site analysis of overlapping YACs allowed fine mapping of these genes and markers along the contig and revealed the presence of four CpG islands. MXI1 and ADRA2A appear to be about 600 kb apart, whereas ADRB1 is separated from ADRA2A by a distance larger than previously reported.     

A Distributed Algorithm for Content Based Indexing of Images by Projections on Ritz Primary Images

Large collections of images can be indexed by their projections on a few “primary” images. The optimal primary images are the eigenvectors of a large covariance matrix. We address the problem of computing primary images when access to the images is expensive. This is the case when the images cannot be kept locally, but must be accessed through slow communication such as the Internet, or stored in a compressed form. A distributed algorithm that computes optimal approximations to the eigenvectors (known as Ritz vectors) in one pass through the image set is proposed. When iterated, the algorithm can recover the exact eigenvectors. The widely used SVD technique for computing the primary images of a small image set is a special case of the proposed algorithm. In applications to image libraries and learning, it is necessary to compute different primary images for several sub-categories of the image set. The proposed algorithm can compute these additional primary images “offline”, without the image data. Similar computation by other algorithms is impractical even when access to the images is inexpensive.     

Implications of neuronal diversity on population coding

In many cortical and subcortical areas, neurons are known to modulate their average firing rate in response to certain external stimulus features. It is widely believed that information about the stimulus features is coded by a weighted average of the neural responses. Recent theoretical studies have shown that the information capacity of such a coding scheme is very limited in the presence of the experimentally observed pairwise correlations. However, central to the analysis of these studies was the assumption of a homogeneous population of neurons. Experimental findings show a considerable measure of heterogeneity in the response properties of different neurons. In this study, we investigate the effect of neuronal heterogeneity on the information capacity of a correlated population of neurons. We show that information capacity of a heterogeneous network is not limited by the correlated noise, but scales linearly with the number of cells in the population. This information cannot be extracted by the population vector readout, whose accuracy is greatly suppressed by the correlated noise. On the other hand, we show that an optimal linear readout that takes into account the neuronal heterogeneity can extract most of this information. We study analytically the nature of the dependence of the optimal linear readout weights on the neuronal diversity. We show that simple online learning can generate readout weights with the appropriate dependence on the neuronal diversity, thereby yielding efficient readout.     

Changing trends in three decades of psychotherapy research: The flight from theory into pragmatics.

Reviews 252 empirical studies of psychotherapy published in the Journal of Consulting and Clinical Psychology in the years 1967/1968, 1977/1978, and 1987/1988. Articles were rated on variables related to theoretical relevance, clinical validity, and methodology. It is shown that the main trend over this period of time has been a decline in theory-guided and a rise in pragmatic, clinically oriented research. Related changes in specific norms and practices in this area are illustrated. The disadvantages of a purely empirical approach to psychotherapy research are discussed, and recommendations are made in light of the distinction between the different aims of pragmatic and theoretical research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporary Heating in Construction Contracts

It appears that in construction projects extending through winter with freezing temperatures, the cost of temporary heating is not always equitably resolved between the parties in a contract. Although existing guidelines have been initiated since 1964 by the construction industry, the bid allowances in calendar days and cost perdiem of heating, as suggested, have not been implemented. The three case studies described with varying structures and heating systems, show how heating costs are affected by changes beyond the General Contractor's control. These costs can be substantial; however, they can be minimized if owner, designer, contractor and mechanical subcontractor can cooperate.