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排序方式: 共有73条查询结果,搜索用时 15 毫秒
1.
Abstract. Both linear and non-linear time series can have directional features which can be used to enhance the modelling and investigation of linear or non-linear autoregressive statistical models. For this purpose, reversed p th-order residuals are introduced. Cross-correlations of residuals and squared reversed residuals allow extensions of current model identification ideas. Quadratic types of partial autocorrelation functions are introduced to assess dependence associated with non-linear models which nevertheless have linear autoregressive correlation structures. The use of these residuals and their cross-correlation functions is exemplified empirically on some deseasonalized river flow data for which a first-order autoregressive model is a satisfactory second-order fit. Parallel theoretical computations are undertaken for the non-linear first-order random coefficient autoregressive model and comparisons are made. While the data are shown to be strongly non-linear, their correlational signatures are found to be convincingly different from those of a first-order autoregressive model with random coefficients. 相似文献
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In the data retrieval process of the Data recommendation system, the matching prediction and similarity identification take place a major role in the ontology. In that, there are several methods to improve the retrieving process with improved accuracy and to reduce the searching time. Since, in the data recommendation system, this type of data searching becomes complex to search for the best matching for given query data and fails in the accuracy of the query recommendation process. To improve the performance of data validation, this paper proposed a novel model of data similarity estimation and clustering method to retrieve the relevant data with the best matching in the big data processing. In this paper advanced model of the Logarithmic Directionality Texture Pattern (LDTP) method with a Metaheuristic Pattern Searching (MPS) system was used to estimate the similarity between the query data in the entire database. The overall work was implemented for the application of the data recommendation process. These are all indexed and grouped as a cluster to form a paged format of database structure which can reduce the computation time while at the searching period. Also, with the help of a neural network, the relevancies of feature attributes in the database are predicted, and the matching index was sorted to provide the recommended data for given query data. This was achieved by using the Distributional Recurrent Neural Network (DRNN). This is an enhanced model of Neural Network technology to find the relevancy based on the correlation factor of the feature set. The training process of the DRNN classifier was carried out by estimating the correlation factor of the attributes of the dataset. These are formed as clusters and paged with proper indexing based on the MPS parameter of similarity metric. The overall performance of the proposed work can be evaluated by varying the size of the training database by 60%, 70%, and 80%. The parameters that are considered for performance analysis are Precision, Recall, F1-score and the accuracy of data retrieval, the query recommendation output, and comparison with other state-of-art methods. 相似文献
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Aikaterini Kefala Maria Amprazi Efstratios Mylonas Dina Kotsifaki Mary Providaki Charalambos Pozidis Melina Fotiadou Michael Kokkinidis 《International journal of molecular sciences》2021,22(4)
Recurrent protein folding motifs include various types of helical bundles formed by α-helices that supercoil around each other. While specific patterns of amino acid residues (heptad repeats) characterize the highly versatile folding motif of four-α-helical bundles, the significance of the polypeptide chain directionality is not sufficiently understood, although it determines sequence patterns, helical dipoles, and other parameters for the folding and oligomerization processes of bundles. To investigate directionality aspects in sequence-structure relationships, we reversed the amino acid sequences of two well-characterized, highly regular four-α-helical bundle proteins and studied the folding, oligomerization, and structural properties of the retro-proteins, using Circular Dichroism Spectroscopy (CD), Size Exclusion Chromatography combined with Multi-Angle Laser Light Scattering (SEC-MALS), and Small Angle X-ray Scattering (SAXS). The comparison of the parent proteins with their retro-counterparts reveals that while the α-helical character of the parents is affected to varying degrees by sequence reversal, the folding states, oligomerization propensities, structural stabilities, and shapes of the new molecules strongly depend on the characteristics of the heptad repeat patterns. The highest similarities between parent and retro-proteins are associated with the presence of uninterrupted heptad patterns in helical bundles sequences. 相似文献
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This paper is devoted to eliminating the noise from the measuring of directional thermal radiation for ground objects. Specifically, we think that the noise is mainly due to the variance of components in the field of view of the sensor with the view angle changing and to the heat balance change on the ground during the period of measurement. The authors present two new observation methods named as "constant area method by thermal camera" and "concurrent method by dual sensors" respectively. The experiments show that the data obtained by these methods abide by some regularly directional distribution, which is totally different from the data from the former methods. The analysis of the major factors in the directionality of thermal radiation is also made in the paper. 相似文献
7.
Mariana Mazzucato 《Industry and innovation》2016,23(2):140-156
Many countries are pursuing innovation-led “smart” growth, which requires long-run strategic investments and public policies that aim to create and shape markets, rather than just “fixing” markets or systems. Market creation has characterized the kind of mission-oriented investments that led to putting a man on the moon and are currently galvanizing green innovation. Mission-oriented innovation has required public agencies to not only “de-risk” the private sector, but also to lead the direct creation of new technological opportunities and market landscapes. This paper considers four key issues that arise from a market-creating framework for policy: (1) decision-making on the direction of change; (2) the nature of (public and private) organizations that can welcome the underlying uncertainty and discovery process; (3) the evaluation of mission-oriented and market-creation policies; and (4) the ways in which both risks and rewards can be shared so that smart growth can also result in inclusive growth. 相似文献
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《Journal of Adhesion Science and Technology》2013,27(1):69-86
The effects of 248 nm KrF excimer laser irradiation on a pressure-sensitive adhesive tape bonded to a glass substrate were investigated as a possible method to evaluate the quality of adhesion, as well as the directionality induced during manufacture. The model pressure-sensitive tape consisted of biaxially-oriented polypropylene (PP) tape coated with a hot-melt rubber resin. Analysis of the front-shot experiments, which were performed by irradiation through the PP backing, allowed correlation between the excimer laser irradiation-induced detachment and the peel adhesion strength. For this purpose, peel tests were performed before and after laser shots. The directionality induced during manufacture resulted in a more ablated area in the strength direction than in the transverse direction when the bonded tapes were irradiated with an elliptically-shaped laser beam above the ablation threshold. A correlation was found between the detachment bubbles created by irradiation below the ablation threshold and their respective peel adhesion values, which allows us to evaluate the quality of adhesion for pressure-sensitive tapes. Thus, a method to evaluate the quality of adhesion using an excimer laser is proposed based on the findings of this work. 相似文献
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Shape‐Shifting 3D Protein Microstructures with Programmable Directionality via Quantitative Nanoscale Stiffness Modulation
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Mian Rong Lee In Yee Phang Yan Cui Yih Hong Lee Xing Yi Ling 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(6):740-748
The ability to shape‐shift in response to a stimulus increases an organism's survivability in nature. Similarly, man‐made dynamic and responsive “smart” microtechnology is crucial for the advancement of human technology. Here, 10–30 μm shape‐changing 3D BSA protein hydrogel microstructures are fabricated with dynamic, quantitative, directional, and angle‐resolved bending via two‐photon photolithography. The controlled directional responsiveness is achieved by spatially controlling the cross‐linking density of BSA at a nanometer lengthscale. Atomic force microscopy measurements of Young's moduli of structures indicate that increasing the laser writing distance at the z‐axis from 100–500 nm decreases the modulus of the structure. Hence, through nanoscale modulation of the laser writing z‐layer distance at the nanoscale, control over the cross‐linking density is possible, allowing for the swelling extent of the microstructures to be quantified and controlled with high precision. This method of segmented moduli is applied within a single microstructure for the design of shape‐shifting microstructures that exhibit stimulus‐induced chirality, as well as for the fabrication of a free‐standing 3D microtrap which is able to open and close in response to a pH change. 相似文献