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排序方式: 共有1069条查询结果,搜索用时 921 毫秒
41.
Giannakeas N Kalatzis F Tsipouras MG Fotiadis DI 《Computer methods and programs in biomedicine》2012,106(1):1-13
In this work, an efficient method for spot addressing in images, which are generated by the scanning of hexagonal structured microarrays, is proposed. Initially, the blocks of the image are separated using the projections of the image. Next, all the blocks of the image are processed separately for the detection of each spot. The spot addressing procedure begins with the detection of the high intensity objects, which are probably the spots of the image. Next, the Growing Concentric Hexagon algorithm, which uses the properties of the hexagonal grid, is introduced for the detection of the non-hybridized spots. Finally, the Voronoi diagram is applied to the centers of the detected spots for the gridding of the image. The method is evaluated using spots generated from the scanning of the Beadchip of Illumina, which is used for the detection of Single Nucleotide Polymorphisms in the human genome, and uses hexagonal structure for the location of the spots. For the evaluation, the detected centers for each of the spot in the image are compared to the centers of the annotation, obtaining up to 98% accuracy for the spot addressing procedure. 相似文献
42.
Isolde Adler Frederic Dorn Fedor V. Fomin Ignasi Sau Dimitrios M. Thilikos 《Algorithmica》2012,64(1):69-84
Minor Containment is a fundamental problem in Algorithmic Graph Theory used as a subroutine in numerous graph algorithms. A model of a graph H in a graph G is a set of disjoint connected subgraphs of G indexed by the vertices of H, such that if {u,v} is an edge of H, then there is an edge of G between components C u and C v . A graph H is a minor of G if G contains a model of H as a subgraph. We give an algorithm that, given a planar n-vertex graph G and an h-vertex graph H, either finds in time $\mathcal{O}(2^{\mathcal{O}(h)} \cdot n +n^{2}\cdot\log n)$ a model of H in G, or correctly concludes that G does not contain H as a minor. Our algorithm is the first single-exponential algorithm for this problem and improves all previous minor testing algorithms in planar graphs. Our technique is based on a novel approach called partially embedded dynamic programming. 相似文献
43.
Web caching in broadcast mobile wireless environments 总被引:1,自引:0,他引:1
Effectively exploiting available communication bandwidth and client resources is vital in wireless mobile environments. One technique for doing so is client-side data caching, which helps reduce latency and conserve network resources. The SliCache generic self-tunable cache-replacement policy addresses these issues by using intelligent slicing of the cache space and novel methods for selecting which objects to purge. Performance evaluations show that SliCache improves mobile clients' access to Web objects compared to other common policies. 相似文献
44.
Constantinos Tsanaktsidis Konstantinos Spinthiropoulos George Tzilantonis Christos Katsaros 《Petroleum Science and Technology》2016,34(13):1121-1128
The use of biodiesel fuel is becoming increasingly imperative nowadays and it is necessary to know the change of density. In this work the variation of density of diesel-biodiesel blends across the scale of 0–100% by adding each time 2% biodiesel and then measuring the density of three different temperatures (5, 15, 25°C) covering and the usual scale of temperatures the use of mixtures of diesel-biodiesel. Through the extraction of equations can be known in advance the relationship of density of diesel-biodiesel blend, and temperature that is used. 相似文献
45.
Sofia Papadaki Magdalini Krokida Dimitrios Economides Emmanuel Koukios 《Drying Technology》2014,32(12):1500-1511
This article presents a study of the effect of drying methods on dyeing capacity of widespread European flora dyestuff plant materials. The natural colorants, derived from the selected plant materials, were applied on chemical pulp in order to examine their dyeability. In this work, three different drying methods were examined—the natural, the air-, and the freeze-drying method—in various conditions. The plant materials that were dried naturally show weak dyeing results in comparison with the air- and freeze-dried materials. Freeze drying significantly improved the dyeing capacity of dyestuff plant materials with high initial moisture content. On the other hand, air drying at low temperature and high relative humidity improved the dyeing capacity of plant materials with low initial moisture content. 相似文献
46.
Sokratis N. Iliopoulos Yassir El Khattabi Dimitrios G. Aggelis 《Journal of Nondestructive Evaluation》2016,35(3):37
Despite the fact that concrete is the most widely used construction material, conventional techniques for the estimation of the mechanical properties are only applicable to the hardened material. Moreover, concerning the fresh concrete examination, the already existing techniques provide only qualitative information, are not representative over the full time period of curing, setting and hardening or have limited accuracy and repeatability. In this study, the acoustic emission (AE) technique is employed in order to investigate the activity within fresh concrete as early as a few minutes after mixing. Several processes like settlement, segregation, formation and migration of air bubbles, as well as formation of hydrates produce AEs which so far have not been properly examined in literature. The first and foremost goal is to check the capacity of the new AE setup to record emissions earlier than previous studies (just after casting). The next goal concerns the possibility to characterize the different types of emissions relatively to their original source mechanism while the final goal would be the investigation of possible correlations between the early age acoustic activity and the final mechanical properties. For this reason, an AE setup is applied utilizing the favorable wave transmission properties of the metal casting molds, which act as a sort of waveguide. After validating its sensitivity, several laboratory tests are performed in concrete with varying water and aggregate content. It is found that the rate of AE activity follows trends similar to the typical hydration curves known from literature and is also indicative of the mix parameters. Finally, it should be mentioned that it is the first study that exploits the acoustic activity as early as the moment of mixing while apart from the number of emissions which is usually examined, the monitoring includes waveform parameters that show strong characterization potential. 相似文献
47.
48.
Colin Robert Dimitrios Mamalis Winifred Obande Vasileios Koutsos Conchúr M. Ó Brádaigh Dipa Ray 《应用聚合物科学杂志》2021,138(40):51188
Fiber-metal laminates (FMLs) offer the superior characteristics of polymer composites (i.e., light weight, high strength and stiffness) with the ductility and fracture strength of metals. The bond strength between the two dissimilar materials, composite and metal, dictates the properties and performance of the FMLs. The bonding becomes more critical when the polymer matrix is thermoplastic and hydrophobic in nature. This work employed a novel bonding technique between thermoplastic composites and a metal layer using six different combinations of organic coatings. The flexural, and interlaminar shear strength of the thermoplastic fiber metal laminates (TP-FMLs) were examined to investigate the bond strengths in the different cases along with fracture characteristics revealed from the tested samples using scanning electron microscopy. The viscoelastic performance of the fabricated TP-FMLs were also investigated using the dynamic mechanical thermal analysis method. 相似文献
49.
The hurdle effect of osmotic pretreatment and high‐pressure cold pasteurisation on the shelf‐life extension of fresh‐cut tomatoes
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Efimia K. Dermesonlouoglou Varvara Andreou Zacharias Alexandrakis George J. Katsaros Maria C. Giannakourou Petros S. Taoukis 《International Journal of Food Science & Technology》2017,52(4):916-926
Tomatoes are perishable products due to the activity of microorganisms and endogenous enzymes. The objective was to produce cut tomatoes with extended shelf life, using the combined hurdle effect of osmotic pretreatment (OD) and high pressure (HP), instead of a conventional one‐step thermal process. Samples were processed in a multicomponent osmotic solution at 35 °C, subsequently cold‐pasteurised in pack at 600 MPa and stored at 5–15 °C. Quality deterioration during isothermal and nonisothermal storage was kinetically modelled. Both OD process and OD‐HP combined process caused an increase in lycopene content that was well retained. Texture, colour and flavour of treated samples were evaluated as similar to fresh, with OD‐HP samples showing better retention during storage. Being microbiologically stable, shelf life of OD‐HP samples was limited by sensory deterioration, whereas OD samples were rejected due to eventual microbial growth. Shelf life of OD and OD‐HP samples was estimated at 77 and 181 days, respectively, at 5 °C. 相似文献
50.
Experimental protein structures provide spatial information at the atomic level. A further dimension, time, is supplemented by molecular dynamics. Since the pioneering work on the 58-residue inhibitor of bovine pancreatic trypsin in the group of Martin Karplus in the seventies, molecular dynamics simulations have shown that the intrinsic flexibility of proteins is essential for their function. Here, we review simulation studies of bromodomains. These protein modules are involved in the recognition of acetylated lysine side chains, a post-translational modification frequently observed in histone tails. The molecular dynamics simulations have unmasked: (i) the large plasticity of the loops lining the acetyl-lysine binding site (coupled to its self-occlusion), and (ii) multiple binding modes of acetyl-lysine. These simulation results suggest that recognition of histone tails by bromodomains is modulated by their intrinsic flexibility, and further corroborate the utility of molecular dynamics in understanding (macro)molecular recognition. 相似文献