Статті в журналах з теми "Homogeneous and heterogeneous sets"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Homogeneous and heterogeneous sets.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Homogeneous and heterogeneous sets".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Ahmed, Sohail, Hang Xu, and Qiang Sun. "Stagnation Flow of a SWCNT Nanofluid towards a Plane Surface with Heterogeneous-Homogeneous Reactions." Mathematical Problems in Engineering 2020 (April 30, 2020): 1–12. http://dx.doi.org/10.1155/2020/3265143.
Повний текст джерелаАнотація:
The homogeneous-heterogeneous reaction in the boundary layer flow of a water-based nanofluid in the stagnation-point region of a plane surface is investigated. The type of small particles explored here is the single-walled carbon nanotubes. The homogeneous nanofluid model is employed for description of behaviours of nanofluids. Here, the homogeneous (bulk) reaction is isothermal cubic autocatalytic, while the heterogeneous (surface) reaction is single, isothermal, and first order. The steady state of this system is analysed in detail, with equal diffusion coefficients being considered for both reactants and autocatalysts. Multiple solutions of the reduced system are captured for some particular sets of physical parameters, which seem to be overlooked in all previous published works with regard to studies of homogeneous-heterogeneous reactions modeled by homogeneous nanofluid models. Besides, we discover the significant limitation of previous conclusion about that the solutions by homogeneous nanofluid flow models can be recovered from those by regular fluids.
2
Gerger, Gernot, Helmut Leder, Stella J. Faerber, and Claus-Christian Carbon. "When the Others Matter." Swiss Journal of Psychology 70, no. 2 (January 2011): 75–83. http://dx.doi.org/10.1024/1421-0185/a000041.
Повний текст джерелаАнотація:
Although innovativeness is an important variable in product design, we know little about its appreciation. We studied how appreciation of innovativeness and its dynamics depends on the heterogeneity of the context in which it appears. We employed a test-retest design in which appreciation of car interior designs was tested before and after repeated evaluations. We tested heterogeneous stimulus sets (highly and lowly innovative designs together; Experiment 1) and homogeneous stimulus sets (highly or lowly innovative designs; Experiment 2). The known effect ( Carbon, Hutzler, & Minge, 2006 ; Carbon & Leder, 2005 ) of a selective increase in attractiveness ratings for highly innovative stimuli after repeated evaluations was only obtained for heterogeneous sets. In homogeneous sets, both highly and lowly innovative interiors were rated similarly and showed similar dynamics. Experiment 3 was a shorter version of Experiment 1, which ruled out differences in experimental design (more ratings and longer duration in Experiment 1) as the cause of the differences. High innovativeness was found to show a specific increase in attractiveness ratings only when innovativeness was made apparent by presenting stimuli in heterogeneous sets. Thus, awareness of variation in innovativeness as a relevant stimulus dimension is a key feature regarding its effect on appreciation.
3
Belke, Eva, Antje S. Meyer, and Markus F. Damian. "Refractory effects in picture naming as assessed in a semantic blocking paradigm." Quarterly Journal of Experimental Psychology Section A 58, no. 4 (May 2005): 667–92. http://dx.doi.org/10.1080/02724980443000142.
Повний текст джерелаАнотація:
In the cyclic semantic blocking paradigm participants repeatedly name sets of objects with semantically related names ( homogeneous sets) or unrelated names ( heterogeneous sets). The naming latencies are typically longer in related than in unrelated sets. In Experiment 1 we replicated this semantic blocking effect and demonstrated that the effect only arose after all objects of a set had been shown and named once. In Experiment 2, the objects of a set were presented simultaneously (instead of on successive trials). Evidence for semantic blocking was found in the naming latencies and in the gaze durations for the objects, which were longer in homogeneous than in heterogeneous sets. For the gaze-to-speech lag between the offset of gaze on an object and the onset of the articulation of its name, a repetition priming effect was obtained but no blocking effect. Experiment 3 showed that the blocking effect for speech onset latencies generalized to new, previously unnamed lexical items. We propose that the blocking effect is due to refractory behaviour in the semantic system.
4
Adzhiev, Valery, Elena Kartasheva, Tosiyasu Kunii, Alexander Pasko, and Benjamin Schmitt. "Hybrid Cellular-functional Modeling of Heterogeneous Objects." Journal of Computing and Information Science in Engineering 2, no. 4 (December 1, 2002): 312–22. http://dx.doi.org/10.1115/1.1559580.
Повний текст джерелаАнотація:
An approach to modeling heterogeneous objects as multidimensional point sets with multiple attributes (hypervolumes) is presented. Attributes given at each point represent object properties of arbitrary nature (material, physical, etc.). A proposed theoretical framework is based on a hybrid model of geometry and attributes combining a cellular representation and a functionally based constructive representation of dimensionally non-homogeneous entities. Hypervolume model components such as objects, operations and relations are introduced and outlined. We present examples of modeling a multi-layer geological structure with cavities and wells, time-dependent adaptive mesh generation, and conversion of a 3D implicit complex to the cellular representation.
5
Haidari, Abedin, and Amir T. Payandeh Najafabadi. "CHARACTERIZATION ORDERING RESULTS FOR LARGEST ORDER STATISTICS FROM HETEROGENEOUS AND HOMOGENEOUS EXPONENTIATED GENERALIZED GAMMA VARIABLES." Probability in the Engineering and Informational Sciences 33, no. 3 (June 27, 2018): 460–70. http://dx.doi.org/10.1017/s0269964818000220.
Повний текст джерелаАнотація:
The main aim of this paper is to present two new results concerning the characterization of likelihood ratio and reversed hazard rate orders between largest order statistics from two sets of independent heterogeneous and homogeneous exponentiated generalized gamma distributed random variables. These characterization results complete and strengthen some previous ones in the literature.
6
Mohammadi, Ali, and Mohammad Farhadian. "Genetic evaluation of growth traits in Iranian Kordi Sheep using random regression model with homogeneous and heterogeneous residual variances." Genetika 49, no. 2 (2017): 469–82. http://dx.doi.org/10.2298/gensr1702469m.
Повний текст джерелаАнотація:
The purpose of this study was estimation of genetic parameter using random regression model (RRM) with various error variance in Iranian Kordi sheep. The data (consisting of 7875 weight records from birth to 360 days of age) were collected during the period 2000 to 2013 from the rearing and breeding station of Kordi sheep in Shirvan, Iran. The independent variables were Legendre polynomials (LP) of age at weighing and orders of fit from 2 to 5 were considered. Analyses were carried out fitting sets of random regression coefficients due to direct additive genetic, direct and maternal permanent environmental effects, with heterogeneous and homogeneous error variances. To compare the model were used different criteria such as LogL, AIC, BIC and LRT. The best fitting RRM among homogeneous error variance was the model with a LP of fourth order for fixed effect, fourth order for direct additive genetic and fifth order for direct and maternal permanent environmental effects (model 4455). Among the models with heterogeneous error variances different, model 7 (Heterogeneous error variances of 72 various classes), was selected as the best model. The variances increased along the trajectory from 3.75 to 12.81, 4.43 to 30.28 and 1.49 to 8.49; 0.25 to 27.94, 0.03 to 12.32 and 0.15 to 22.66 for direct additive genetic, direct and maternal permanent environmental effect by homogeneous and heterogeneous error variances, respectively. The direct heritability ranged from 0.15 to 0.41 and 0.11 to 0.56 by homogeneous and heterogeneous error variances, respectively. Genetic correlation between adjacent test days was more than between distant test days. This research has demonstrated the possibility of application of RRM with heterogeneous error variance for genetic evaluation of Iranian Kordi Sheep.
7
Brown, D. D., F. M. Collins, W. P. Duprex, M. D. Baron, T. Barrett, and B. K. Rima. "‘Rescue’ of mini-genomic constructs and viruses by combinations of morbillivirus N, P and L proteins." Journal of General Virology 86, no. 4 (April 1, 2005): 1077–81. http://dx.doi.org/10.1099/vir.0.80804-0.
Повний текст джерелаАнотація:
Chloramphenicol acetyltransferase (CAT)-expressing negative-sense mini-genomic constructs of measles virus (MV) and rinderpest virus (RPV) were rescued by standard technology with helper plasmids expressing the nucleocapsid (N), phospho- (P) and large (L) proteins of MV, canine distemper virus (CDV) or RPV in order to determine whether the proteins of different viruses can function together. Homogeneous sets consisting of N, P and L plasmids derived from one virus were able to generate reporter gene expression from either mini-genomic construct. Heterogeneous sets of proteins from different viruses were not functional, with the exception that a low level of activity was obtained when MV N and P protein were combined with RPV L protein in the rescue of the MV mini-genomic construct, or CDV N was combined with RPV P and L in the rescue of the RPV mini-genome. However, only homogeneous sets of plasmids were able to rescue infectious virus from full-length anti-genome-expressing plasmids.
8
Maxim, Anca, and Constantin-Florin Caruntu. "Coalitional Distributed Model Predictive Control Strategy for Vehicle Platooning Applications." Sensors 22, no. 3 (January 27, 2022): 997. http://dx.doi.org/10.3390/s22030997.
Повний текст джерелаАнотація:
This work aims at developing and testing a novel Coalitional Distributed Model Predictive Control (C-DMPC) strategy suitable for vehicle platooning applications. The stability of the algorithm is ensured via the terminal constraint region formulation, with robust positively invariant sets. To ensure a greater flexibility, in the initialization part of the method, an invariant table set is created containing several invariant sets computed for different constraints values. The algorithm was tested in simulation, using both homogeneous and heterogeneous initial conditions for a platoon with four homogeneous vehicles, using a predecessor-following, uni-directionally communication topology. The simulation results show that the coalitions between vehicles are formed in the beginning of the experiment, when the local feasibility of each vehicle is lost. These findings successfully prove the usefulness of the proposed coalitional DMPC method in a vehicle platooning application, and illustrate the robustness of the algorithm, when tested in different initial conditions.
9
Farooq, Umer, Husain Parvez, Habib Mehrez, and Zied Marrakchi. "Exploration of Heterogeneous FPGA Architectures." International Journal of Reconfigurable Computing 2011 (2011): 1–18. http://dx.doi.org/10.1155/2011/121404.
Повний текст джерелаАнотація:
Mesh-based heterogeneous FPGAs are commonly used in industry and academia due to their area, speed, and power benefits over their homogeneous counterparts. These FPGAs contain a mixture of logic blocks and hard blocks where hard blocks are arranged in fixed columns as they offer an easy and compact layout. However, the placement of hard-blocks in fixed columns can potentially lead to underutilization of logic and routing resources and this problem is further aggravated with increase in the types of hard-blocks. This work explores and compares different floor-planning techniques of mesh-based FPGA to determine their effect on the area, performance, and power of the architecture. A tree-based architecture is also presented; unlike mesh-based architecture, the floor-planning of heterogeneous tree-based architecture does not affect its routing requirements due to its hierarchical structure. Both mesh and tree-based architectures are evaluated for three sets of benchmark circuits. Experimental results show that a more flexible floor-planning in mesh-based FPGA gives better results as compared to the column-based floor-planning. Also it is shown that compared to different floor-plannings of mesh-based FPGA, tree-based architecture gives better area, performance, and power results.
10
Kraus, Alexander E., Evgeny I. Kraus, and Ivan I. Shabalin. "Simulation of a Group Impact on a Heterogeneous Target of Finite Thickness." Journal of Siberian Federal University. Mathematics & Physics 14, no. 6 (December 2021): 700–711. http://dx.doi.org/10.17516/1997-1397-2021-14-6-700-711.
Повний текст джерелаАнотація:
Numerical simulation of the processes of high-speed loading of homogeneous and heteroge- neous targets by single projectiles, as well as by a group of projectiles with the same parameters in mass and momentum, has been carried out. Based on a comparison of the numerical simulation results for loading targets with different sets of projectiles, it is found that a projectile in the form of a ring knocks out the maximum hole in the target in terms of geometric dimensions, while a set of seven small disks removes the maximum mass from the target. The ring impact forms a continuous spall plate, which outruns the cloud of fragments of the destroyed material. Adding more than 5% of ceramics to the aluminum target volume does not allow the projectiles to penetrate through
11
Zhang, Haiming, Mingchang Wang, Fengyan Wang, Guodong Yang, Ying Zhang, Junqian Jia, and Siqi Wang. "A Novel Squeeze-and-Excitation W-Net for 2D and 3D Building Change Detection with Multi-Source and Multi-Feature Remote Sensing Data." Remote Sensing 13, no. 3 (January 27, 2021): 440. http://dx.doi.org/10.3390/rs13030440.
Повний текст джерелаАнотація:
Building Change Detection (BCD) is one of the core issues in earth observation and has received extensive attention in recent years. With the rapid development of earth observation technology, the data source of remote sensing change detection is continuously enriched, which provides the possibility to describe the spatial details of the ground objects more finely and to characterize the ground objects with multiple perspectives and levels. However, due to the different physical mechanisms of multi-source remote sensing data, BCD based on heterogeneous data is a challenge. Previous studies mostly focused on the BCD of homogeneous remote sensing data, while the use of multi-source remote sensing data and considering multiple features to conduct 2D and 3D BCD research is sporadic. In this article, we propose a novel and general squeeze-and-excitation W-Net, which is developed from U-Net and SE-Net. Its unique advantage is that it can not only be used for BCD of homogeneous and heterogeneous remote sensing data respectively but also can input both homogeneous and heterogeneous remote sensing data for 2D or 3D BCD by relying on its bidirectional symmetric end-to-end network architecture. Moreover, from a unique perspective, we use image features that are stable in performance and less affected by radiation differences and temporal changes. We innovatively introduced the squeeze-and-excitation module to explicitly model the interdependence between feature channels so that the response between the feature channels is adaptively recalibrated to improve the information mining ability and detection accuracy of the model. As far as we know, this is the first proposed network architecture that can simultaneously use multi-source and multi-feature remote sensing data for 2D and 3D BCD. The experimental results in two 2D data sets and two challenging 3D data sets demonstrate that the promising performances of the squeeze-and-excitation W-Net outperform several traditional and state-of-the-art approaches. Moreover, both visual and quantitative analyses of the experimental results demonstrate competitive performance in the proposed network. This demonstrates that the proposed network and method are practical, physically justified, and have great potential application value in large-scale 2D and 3D BCD and qualitative and quantitative research.
12
Simmons, Mark P., Li-Bing Zhang, Colleen T. Webb, Aaron Reeves, and Jeremy A. Miller. "The relative performance of Bayesian and parsimony approaches when sampling characters evolving under homogeneous and heterogeneous sets of parameters." Cladistics 22, no. 2 (April 2006): 171–85. http://dx.doi.org/10.1111/j.1096-0031.2006.00098.x.
Повний текст джерела
13
Schoenberg, Michael, and Francis Muir. "A calculus for finely layered anisotropic media." GEOPHYSICS 54, no. 5 (May 1989): 581–89. http://dx.doi.org/10.1190/1.1442685.
Повний текст джерелаАнотація:
Matrix algebra and group theory combine to offer a formalism for the simple calculation of the elastic, anisotropic, homogeneous medium which is equivalent, in the long‐wavelength limit, to a heterogeneous distribution of fine layers, each layer itself an elastic anisotropic medium. The properties of each anisotropic constituent in a set of fine layers map to an element of a commutative group. A reverse mapping returns the material properties of the constituent. Adding group elements gives the group element for the homogeneous medium equivalent to a heterogeneous set of layers. Addition of an inverse element—that is subtraction—provides the means to remove a set of layers from an anisotropic medium; then, if the remaining layer is a stable anisotropic medium, a valid decomposition of the original medium into anisotropic constituents is obtained. Within the group structure, eight subgroups corresponding to eight types of elastic symmetry systems may be identified, immediately yielding the symmetry of the equivalent medium, given the symmetry of its constituents. Sets of parallel fractures or aligned microcracks are also represented as group elements, allowing fractures and anisotropic rocks to be manipulated in a consistent and uniform manner. These group elements depend on at most six fracture parameters and are independent of the properties of the material in which the fractures are embedded. Multiple sets of fractures are easily taken into account by rotating (back in model space) a rock to a coordinate system appropriate to each fracture system, and then adding the appropriate fracture system group element.
14
Zhang, Yiying. "On transform orders for largest claim amounts." Journal of Applied Probability 58, no. 4 (November 22, 2021): 1064–85. http://dx.doi.org/10.1017/jpr.2021.12.
Повний текст джерелаАнотація:
AbstractThis paper investigates the ordering properties of largest claim amounts in heterogeneous insurance portfolios in the sense of some transform orders, including the convex transform order and the star order. It is shown that the largest claim amount from a set of independent and heterogeneous exponential claims is more skewed than that from a set of independent and homogeneous exponential claims in the sense of the convex transform order. As a result, a lower bound for the coefficient of variation of the largest claim amount is established without any restrictions on the parameters of the distributions of claim severities. Furthermore, sufficient conditions are presented to compare the skewness of the largest claim amounts from two sets of independent multiple-outlier scaled claims according to the star order. Some comparison results are also developed for the multiple-outlier proportional hazard rates claims. Numerical examples are presented to illustrate these theoretical results.
15
Shreevastava, Shivam, Anoop Kumar Tiwari, and Tanmoy Som. "Intuitionistic Fuzzy Neighborhood Rough Set Model for Feature Selection." International Journal of Fuzzy System Applications 7, no. 2 (April 2018): 75–84. http://dx.doi.org/10.4018/ijfsa.2018040104.
Повний текст джерелаАнотація:
Feature selection is one of the widely used pre-processing techniques to deal with large data sets. In this context, rough set theory has been successfully implemented for feature selection of discrete data set but in case of continuous data set it requires discretization, which may cause information loss. Fuzzy rough set theory approaches have also been used successfully to resolve this issue as it can handle continuous data directly. Moreover, almost all feature selection techniques are used to handle homogeneous data set. In this article, the center of attraction is on heterogeneous feature subset reduction. A novel intuitionistic fuzzy neighborhood models have been proposed by combining intuitionistic fuzzy sets and neighborhood rough set models by taking an appropriate pair of lower and upper approximations and generalize it for feature selection, supported with theory and its validation. An appropriate algorithm along with application to a data set has been added.
16
Takbiri-Borujeni, Ali, Vahid Mohammadnia, Mahdi Mansouri-Boroujeni, Hossein Nourozieh, and Payam Kavousi Ghahfarokhi. "Upscaling the Steam-Assisted-Gravity-Drainage Model for Heterogeneous Reservoirs." SPE Journal 24, no. 04 (May 27, 2019): 1681–99. http://dx.doi.org/10.2118/195587-pa.
Повний текст джерелаАнотація:
Summary The effects of heterogeneities in the rock and fluid properties on the governing equations in modeling the steam-assisted-gravity-drainage (SAGD) process are investigated using a spectrum-based upscaling approach. In this approach, heterogeneity is included by assigning random perturbation fields to permeability and thermal diffusivity that hold the assumption of first and second orders of stationarity. Heat and mass-transport parameters and dependent variables (e.g., temperature and viscosity) that are affected by heterogeneity are represented by their mean and perturbations around the mean values. Substituting the perturbed variables and coefficients into the basic governing equations (heat-diffusion and Darcy equations) results in new sets of stochastic partial-differential equations that include mean and perturbation. Mean equations are essentially upscaled new governing equations that include the autocorrelations and cross correlations between different perturbed quantities. The cross correlations are derived by applying the Fourier-Stieltjes transform. Verification and validation of the developed results for the heat-diffusion equation are performed using numerical simulations with synthetic heterogeneities. The upscaled equations embrace the heterogeneity in permeability and thermal diffusivity and can predict the flow rate and shape of the steam chamber. The upscaled model is compared with the homogeneous model, developed by Butler (1991), to quantify the effects of heterogeneities in permeability and thermal diffusivity on the SAGD efficiency. A case is studied by assigning harmonic distribution to the perturbations of thermal diffusivity and permeability. Different cases with different relationships between permeability and thermal-diffusivity fields are considered to investigate their effects on the oil flow rate. The results show that local perturbations decrease the oil flow rate. Furthermore, steam-chamber growth is retarded in a reservoir with local perturbations compared with homogeneous reservoirs. The developed model can be used in the initial stages of SAGD development projects for long-range planning as a guide to find the upper and lower limits of production in reservoirs with heterogeneities.
17
BENOIT, ANNE, YVES ROBERT, and ERIC THIERRY. "ON THE COMPLEXITY OF MAPPING LINEAR CHAIN APPLICATIONS ONTO HETEROGENEOUS PLATFORMS." Parallel Processing Letters 19, no. 03 (September 2009): 383–97. http://dx.doi.org/10.1142/s0129626409000298.
Повний текст джерелаАнотація:
In this paper, we explore the problem of mapping linear chain applications onto large-scale heterogeneous platforms. A series of data sets enter the input stage and progress from stage to stage until the final result is computed. An important optimization criterion that should be considered in such a framework is the latency, or makespan, which measures the response time of the system in order to process one single data set entirely. For such applications, which are representative of a broad class of real-life applications, we can consider one-to-one mappings, in which each stage is mapped onto a single processor. However, in order to reduce the communication cost, it seems natural to group stages into intervals. The interval mapping problem can be solved in a straightforward way if the platform has homogeneous communications: the whole chain is grouped into a single interval, which in turn is mapped onto the fastest processor. But the problem becomes harder when considering a fully heterogeneous platform. Indeed, we prove the NP-completeness of this problem. Furthermore, we prove that neither the interval mapping problem nor the similar one-to-one mapping problem can be approximated in polynomial time by any constant factor (unless P=NP).
18
Pasha, Muhammad Adeel, Umer Farooq, and Bilal Siddiqui. "A framework for high-level simulation and optimization of fine-grained reconfigurable architectures." SIMULATION 95, no. 8 (September 10, 2018): 737–51. http://dx.doi.org/10.1177/0037549718796272.
Повний текст джерелаАнотація:
Field Programmable Gate Arrays (FPGAs), due to their programmability, have become a popular design choice for control and processing blocks of modern-day digital design. However, this flexibility makes them larger, slower, and less power-efficient when compared to Application Specific Integrated Circuits (ASICs). On the other hand, ASICs have their own drawbacks, such as lack of programmability and inflexibility. One potential solution is specialized fine-grained reconfigurable architectures that have improved flexibility over ASICs and better resource utilization than FPGAs. However, designing a fine-grained reconfigurable architecture is a daunting task in itself due to lack of high-level design-flow support. This article proposes an automated design-flow for the system-level simulation, optimization, and resource estimation of generic as well as custom fine-grained reconfigurable architectures. The proposed framework is generic in nature as it can be used for both control-oriented and compute-intensive applications and then generates a homogeneous or heterogeneous reconfigurable architecture for them. Four sets of homogeneous and heterogeneous benchmarks are used in this work to show the efficacy of our proposed design-flow, and simulation results reveal that our framework can generate both generic and custom fine-grained reconfigurable architectures. Moreover, the area and power estimations show that auto-generated domain-specific reconfigurable architectures are 76% and 73% more area and power-efficient, respectively, than generic FPGA-based implementations. These results are consistent with the savings reported for manual designs in the literature.
19
Jameson, A. R. "A New Characterization of Rain and Clouds: Results from a Statistical Inversion of Count Data." Journal of the Atmospheric Sciences 64, no. 6 (June 2007): 2012–28. http://dx.doi.org/10.1175/jas3950.1.
Повний текст джерелаАнотація:
Most variables in meteorology are statistically heterogeneous. The statistics of data from several different locations, then, can be thought of as an amalgamation of information contained in several contributing probability density functions (PDFs) having different sets of parameters, different parametric forms, and different mean values. The frequency distribution of such data, then, will often be multimodal. Usually, however, in order to achieve better sampling, measurements of these variables over an entire set of data gathered at widely disparate locations are processed as though the data were statistically homogeneous, that is, as though they were fully characterized by just one PDF and one single set of parameters having one mean value. Is there, instead, a better way of treating the data in a manner that is consistent with this statistical heterogeneity? This question is addressed here using a statistical inversion technique developed by Tarantola based upon Bayesian methodology. Two examples of disdrometer measurements in real rain, one 16 h and the other 3 min long, reveal the presence of multiple mean values of the counts at all the different drop sizes. In both cases the heterogeneous rain can be decomposed into five–seven statistically homogeneous components, each characterized by its own steady drop size distribution. Concepts such as stratiform versus convective rain can be given more precise meaning in terms of the contributions each component makes to the rain. Furthermore, this discovery permits the explicit inclusion of statistical heterogeneity into some analytic theories.
20
Raveendran, Nishanthi, and Georgy Sofronov. "A Markov Chain Monte Carlo Algorithm for Spatial Segmentation." Information 12, no. 2 (January 30, 2021): 58. http://dx.doi.org/10.3390/info12020058.
Повний текст джерелаАнотація:
Spatial data are very often heterogeneous, which indicates that there may not be a unique simple statistical model describing the data. To overcome this issue, the data can be segmented into a number of homogeneous regions (or domains). Identifying these domains is one of the important problems in spatial data analysis. Spatial segmentation is used in many different fields including epidemiology, criminology, ecology, and economics. To solve this clustering problem, we propose to use the change-point methodology. In this paper, we develop a new spatial segmentation algorithm within the framework of the generalized Gibbs sampler. We estimate the average surface profile of binary spatial data observed over a two-dimensional regular lattice. We illustrate the performance of the proposed algorithm with examples using artificially generated and real data sets.
21
Ćwiklińska-Jurkowska, Małgorzata. "Gene selection ensembles and classifier ensembles for medical diagnosis." Biometrical Letters 56, no. 2 (December 1, 2019): 117–38. http://dx.doi.org/10.2478/bile-2019-0007.
Повний текст джерелаАнотація:
SummaryThe usefulness of combining methods is examined using the example of microarray cancer data sets, where expression levels of huge numbers of genes are reported. Problems of discrimination into two groups are examined on three data sets relating to the expression of huge numbers of genes. For the three examined microarray data sets, the cross-validation errors evaluated on the remaining half of the whole data set, not used earlier for the selection of genes, were used as measures of classifier performance. Common single procedures for the selection of genes—Prediction Analysis of Microarrays (PAM) and Significance Analysis of Microarrays (SAM)—were compared with the fusion of eight selection procedures, or of a smaller subset of five of them, excluding SAM or PAM. Merging five or eight selection methods gave similar results. Based on the misclassification rates for the three examined microarray data sets, for any examined ensemble of classifiers, the combining of gene selection methods was not superior to single PAM or SAM selection for two of the examined data sets. Additionally, the procedure of heterogeneous combining of five base classifiers—k-nearest neighbors, SVM linear and SVM radial with parameter c=1, shrunken centroids regularized classifier (SCRDA) and nearest mean classifier—proved to significantly outperform resampling classifiers such as bagging decision trees. Heterogeneously combined classifiers also outperformed double bagging for some ranges of gene numbers and data sets, but merging is generally not superior to random forests. The preliminary step of combining gene rankings was generally not essential for the performance for either heterogeneously or homogeneously combined classifiers.
22
Hauck, C., M. Böttcher, and H. Maurer. "A new model for quantifying subsurface ice content based on geophysical data sets." Cryosphere Discussions 4, no. 2 (June 25, 2010): 787–821. http://dx.doi.org/10.5194/tcd-4-787-2010.
Повний текст джерелаАнотація:
Abstract. Detailed knowledge of the material properties and internal structures of frozen ground is one of the prerequisites in many permafrost studies. In the absence of direct evidence, such as in-situ borehole measurements, geophysical methods are an increasingly interesting option for obtaining subsurface information on various spatial and temporal scales. The indirect nature of geophysical soundings requires a relation between the measured variables (e.g. electrical resistivity, seismic velocity) and the actual subsurface constituents (rock, water, air, ice). In this work we present a model, which provides estimates of the volumetric fractions of these four phases from tomographic electrical and seismic images. The model is tested using geophysical data sets from two rock glaciers in the Swiss Alps, where ground truth information in form of borehole data is available. First results confirm the applicability of the so-called 4-phase model, which allows to quantify the contributions of ice-, water- and air within permafrost areas as well as detecting the firm bedrock. Apart from a similarly thick active layer with enhanced air content for both rock glaciers, the two case studies revealed a heterogeneous distribution of ice and unfrozen water within rock glacier Muragl, where bedrock was detected at depths of 20–25 m, but a comparatively homogeneous ice body with only minor heterogeneities within rock glacier Murtèl.
23
Zhou, Guangjiao, and Ye Zhang. "Transfer and Association: A Novel Detection Method for Targets without Prior Homogeneous Samples." Remote Sensing 11, no. 12 (June 24, 2019): 1492. http://dx.doi.org/10.3390/rs11121492.
Повний текст джерелаАнотація:
A primary problem faced during previous research was the gap in limited and unbalanced quantity of prior samples between computer classification tasks and targeted remote sensing applications. This paper presents the fusion method to overcome this limitation. It offers a novel method based on knowledge transfer and feature association, a strong combination of transfer learning and data fusion. The former reuses layers trained on complete data sets to compute a mid-level representation of the specific target. The latter brings additional information from heterogeneous sources to enrich the features in the target domain. Firstly, a basic convolutional neural network (B_CNN) is pretrained on to the CIFAR-10 dataset to produce a stable model responsible for general feature extraction from multiple inputs. Secondly, a transfer CNN (Trans_CNN) with fine-tuned and transferred parameters is constraint-trained to fit and switch between differing tasks. Meanwhile, the feature association (FA) frames a new feature space to achieve integration between training and testing samples from different sensors. Finally, on-line detection can be completed based on Trans_CNN to explore a state-of-the-art method to overcome the inadequate sample problems in real remote sensing applications rather than produce an unrolled version of training methods or structural improvement in CNN. Experimental results show that target detection rates without homogeneous prior samples can reach 85%. Under these conditions, the traditional CNN model is invalid.
24
Sterner, Robert W. "Lake Morphometry and Light in the Surface Layer." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 4 (April 1, 1990): 687–92. http://dx.doi.org/10.1139/f90-076.
Повний текст джерелаАнотація:
Mean irradiance in the surface layer was calculated as a percent of incident irradiance using Secchi depths and thermocline depths for two sets of lakes: (1) 20 nearly circular lakes in northwest Minnesota, USA, sampled at a similar season, and (2) 1140 lakes of heterogeneous shapes in Ontario, Canada, sampled throughout the ice-free season. For both, as lake area increased, the thickness of the surface layer increased. Consequently, lakes larger in area had lower mean irradiance in their surface layer. Lake depth had less influence, but in the Ontario lakes, as depth increased, attenuation decreased, and mean irradiance increased. Lake area (log transformed) explained ca. one-half of the variation in mean irradiance in the homogeneous sampling of Minnesota lakes, while area and depth together explained less of the variation in the heterogeneous sampling of Ontario lakes. Shape, i.e. shoreline development, was unimportant compared with the gross measures of size, area and depth. Mean irradiance is complexly related to lake size; when depth increases slowly with area, larger lakes may have lower mean irradiance in their surface layers. But, when depth increases quickly with area, mean irradiance can be unrelated to area.
25
Zhuang, Yulong, Salah Awel, Anton Barty, Richard Bean, Johan Bielecki, Martin Bergemann, Benedikt J. Daurer, et al. "Unsupervised learning approaches to characterizing heterogeneous samples using X-ray single-particle imaging." IUCrJ 9, no. 2 (January 11, 2022): 204–14. http://dx.doi.org/10.1107/s2052252521012707.
Повний текст джерелаАнотація:
One of the outstanding analytical problems in X-ray single-particle imaging (SPI) is the classification of structural heterogeneity, which is especially difficult given the low signal-to-noise ratios of individual patterns and the fact that even identical objects can yield patterns that vary greatly when orientation is taken into consideration. Proposed here are two methods which explicitly account for this orientation-induced variation and can robustly determine the structural landscape of a sample ensemble. The first, termed common-line principal component analysis (PCA), provides a rough classification which is essentially parameter free and can be run automatically on any SPI dataset. The second method, utilizing variation auto-encoders (VAEs), can generate 3D structures of the objects at any point in the structural landscape. Both these methods are implemented in combination with the noise-tolerant expand–maximize–compress (EMC) algorithm and its utility is demonstrated by applying it to an experimental dataset from gold nanoparticles with only a few thousand photons per pattern. Both discrete structural classes and continuous deformations are recovered. These developments diverge from previous approaches of extracting reproducible subsets of patterns from a dataset and open up the possibility of moving beyond the study of homogeneous sample sets to addressing open questions on topics such as nanocrystal growth and dynamics, as well as phase transitions which have not been externally triggered.
26
Plasman, Matthieu, Christel Tiberi, Cecilia Cadio, Anita Thea Saraswati, Gwendoline Pajot-Métivier, and Michel Diament. "From space to lithosphere: inversion of the GOCE gravity gradients. Supply to the Earth’s interior study." Geophysical Journal International 223, no. 1 (June 26, 2020): 398–419. http://dx.doi.org/10.1093/gji/ggaa318.
Повний текст джерелаАнотація:
SUMMARY The emergence of high resolution satellite measurements of the gravitational field (GOCE mission) offers promising perspectives for the study of the Earth’s interior. These new data call for the development of innovant analysis and interpretation methods. Here we combine a forward prism computation with a Bayesian resolution approach to invert for these gravity gradient data configuration. We apply and test our new method on satellite data configuration, that is 225 km height with a global and homogeneous geographic distribution. We first quantify the resolution of our method according to both data and parametrization characteristics. It appears that for reasonable density contrast values (0.1 g cm−3) crustal structures have to be wider than ∼28 km to be detectable in the GOCE signal. Deeper bodies are distinguishable for greater size (35 km size at 50 km depth, ∼80 km at 300 km depth). We invert the six tensor components, among which five are independent. By carefully testing each of them and their different combinations, we enlighten a trade off between the recovery of data and the sensitivity to inversion parameters. We particularly discussed this characteristic in terms of geometry of the synthetic model tested (structures orientation, 3-D geometry, etc.). In terms of RMS value, each component is always better explained if inverted solely, but the result is strongly affected by the inversion parametrization (smoothing, variances, etc.). On the contrary, the simultaneous inversion of several components displays a significant improvement for the global tensor recovery, more dependent on data than on density variance or on smoothness control. Comparing gravity and gradient inversions, we highlight the superiority of the GG data to better reproduce the structures especially in terms of vertical location. We successfully test our method on a realistic case of a complex subduction case for both gradient and gravity data. While the imaging of small crustal structures requires terrestrial gravity data set, the longest wavelength of the slab is well recovered with both data sets. The precision and homogeneous coverage of GOCE data however, counterbalance the heterogeneous and often quite non-existence coverage of terrestrial gravity data. This is particularly true in large areas which requires a coherent assemblage of heterogeneous data sets, or in high relief, vegetally covered and offshore zones.
27
Benot, Marie-Lise, Anne Bonis, Nicolas Rossignol, and Cendrine Mony. "Spatial patterns in defoliation and the expression of clonal traits in grazed meadows." Botany 89, no. 1 (January 2011): 43–54. http://dx.doi.org/10.1139/b10-082.
Повний текст джерелаАнотація:
Clonal plant species dominate meadow vegetation where grazing can generate spatial heterogeneity at different scales and can select for species that express particular sets of clonal traits. This in situ study aimed to characterize fine-grained spatial patterns of defoliation (<1 m) induced by contrasting cattle grazing intensities and to link these spatial patterns with the abundance of species-specific clonal traits. Using correlogams and synthetic spatio-temporal indices, the heterogeneity of vegetation height and leaf damage was monitored along a cattle grazing gradient. Species were identified and their clonal traits retrieved from the database CLO-PLA3. Under moderate grazing, fine-grained spatial patterns of defoliation were not stable over time. Defoliation was heterogeneous during the first months of the grazing season and then became homogeneous. Intensive grazing generated homogeneous defoliation, regardless of the date. In the study meadow, grazing gave rise to communities containing a greater abundance of annual species. However, clonal traits assumed to enable clonal fragments to benefit from heterogeneity do not seem advantageous. Increasing grazing intensity promoted species with clonal traits expected to minimize costs associated with clonality (aboveground clonal growth forms, short-distance lateral spread, and (or) short-lived connections). Ungrazed conditions favoured species with clonal traits associated with a high competitive ability.
28
Hauck, C., M. Böttcher, and H. Maurer. "A new model for estimating subsurface ice content based on combined electrical and seismic data sets." Cryosphere 5, no. 2 (June 1, 2011): 453–68. http://dx.doi.org/10.5194/tc-5-453-2011.
Повний текст джерелаАнотація:
Abstract. Detailed knowledge of the material properties and internal structures of frozen ground is one of the prerequisites in many permafrost studies. In the absence of direct evidence, such as in-situ borehole measurements, geophysical methods are an increasingly interesting option for obtaining subsurface information on various spatial and temporal scales. The indirect nature of geophysical soundings requires a relation between the measured variables (e.g. electrical resistivity, seismic velocity) and the actual subsurface constituents (rock, water, air, ice). In this work, we present a model which provides estimates of the volumetric fractions of these four constituents from tomographic electrical and seismic images. The model is tested using geophysical data sets from two rock glaciers in the Swiss Alps, where ground truth information in form of borehole data is available. First results confirm the applicability of the so-called 4-phase model, which allows to quantify the contributions of ice-, water- and air within permafrost areas as well as detecting solid bedrock. Apart from a similarly thick active layer with enhanced air content for both rock glaciers, the two case studies revealed a heterogeneous distribution of ice and unfrozen water within Muragl rock glacier, where bedrock was detected at depths of 20–25 m, but a comparatively homogeneous ice body with only minor heterogeneities within Murtèl rock glacier.
29
Cilli, Roberto, Alfonso Monaco, Nicola Amoroso, Andrea Tateo, Sabina Tangaro, and Roberto Bellotti. "Machine Learning for Cloud Detection of Globally Distributed Sentinel-2 Images." Remote Sensing 12, no. 15 (July 22, 2020): 2355. http://dx.doi.org/10.3390/rs12152355.
Повний текст джерелаАнотація:
In recent years, a number of different procedures have been proposed for segmentation of remote sensing images, basing on spectral information. Model-based and machine learning strategies have been investigated in several studies. This work presents a comprehensive overview and an unbiased comparison of the most adopted segmentation strategies: Support Vector Machines (SVM), Random Forests, Neural networks, Sen2Cor, FMask and MAJA. We used a training set for learning and two different independent sets for testing. The comparison accounted for 135 images acquired from 54 different worldwide sites. We observed that machine learning segmentations are extremely reliable when the training and test are homogeneous. SVM performed slightly better than other methods. In particular, when using heterogeneous test data, SVM remained the most accurate segmentation method while state-of-the-art model-based methods such as MAJA and FMask obtained better sensitivity and precision, respectively. Therefore, even if each method has its specific advantages and drawbacks, SVM resulted in a competitive option for remote sensing applications.
30
Gao, X. L. "Extended Hill’s lemma for non-Cauchy continua based on the simplified strain gradient elasticity theory." Journal of Micromechanics and Molecular Physics 01, no. 03n04 (October 2016): 1640004. http://dx.doi.org/10.1142/s242491301640004x.
Повний текст джерелаАнотація:
Hill's lemma for the Cauchy continuum has been playing an important role in micromechanics. An extended version of Hill's lemma for non-Cauchy continua is formulated using the simplified strain gradient elasticity theory (SSGET), which contains only one material length scale parameter and can account for the microstructure-dependent strain gradient effect. As a corollary of the extended Hill's lemma, the Hill–Mandel macro-homogeneity condition for non-Cauchy continua is obtained along with the general forms of kinematically and statically admissible boundary conditions that are required for constructing an energetically equivalent homogeneous comparison material. Based on these general forms, four sets of uniform boundary conditions are identified, which are implementable in material tests and can be directly used in homogenization analyses of heterogeneous materials. It is shown that when the strain gradient effect is suppressed, the extended Hill's lemma recovers the classical Hill's lemma for the Cauchy continuum and the extended Hill–Mandel condition reduces to its classical counterpart.
31
Basak, Subhash, and Subhabrata Majumdar. "EDITORIAL: Chemodescriptor Based QSARs of Structurally Homogeneous Versus Heterogeneous Chemical Data Sets: Some Comments on the Congenericity Principle vis-à-vis Diversity Begets Diversity Principle." Current Computer Aided-Drug Design 12, no. 2 (July 13, 2016): 84–86. http://dx.doi.org/10.2174/157340991202160713190446.
Повний текст джерела
32
Gruber, M. A., G. J. Fochesatto, and O. K. Hartogensis. "Sensitivity of large-aperture scintillometer measurements of area-average heat fluxes to uncertainties in topographic heights." Atmospheric Measurement Techniques Discussions 7, no. 1 (January 7, 2014): 33–68. http://dx.doi.org/10.5194/amtd-7-33-2014.
Повний текст джерелаАнотація:
Abstract. Scintillometer measurements allow for estimations of the refractive index structure parameter Cn2 over large areas in the atmospheric surface layer. Turbulent fluxes of heat and momentum are inferred through coupled sets of equations derived from the Monin–Obukhov similarity hypothesis. One-dimensional sensitivity functions have been produced that relate the sensitivity of heat fluxes to uncertainties in single values of beam height over homogeneous and flat terrain. However, real field sites include variable topography and heterogeneous surfaces. We develop here the first analysis of the sensitivity of scintillometer derived sensible heat fluxes to uncertainties in spatially distributed topographic measurements. For large-aperture scintillometers and independent friction velocity u* measurements, sensitivity is shown to be concentrated in areas near the center of the beam path and where the underlying topography is closest to the beam height. Uncertainty may be greatly reduced by focusing precise topographic measurements in these areas. A new two-dimensional variable terrain sensitivity function is developed for quantitative error analysis. This function is compared with the previous one-dimensional sensitivity function for the same measurement strategy over flat and homogeneous terrain. Additionally, a new method of solution to the set of coupled equations is produced that eliminates computational error. The results are produced using a new methodology for error analysis involving distributed parameters that may be applied in other disciplines.
33
Wang, Huai-Chun, Edward Susko, and Andrew J. Roger. "The Relative Importance of Modeling Site Pattern Heterogeneity Versus Partition-Wise Heterotachy in Phylogenomic Inference." Systematic Biology 68, no. 6 (April 23, 2019): 1003–19. http://dx.doi.org/10.1093/sysbio/syz021.
Повний текст джерелаАнотація:
Abstract Large taxa-rich genome-scale data sets are often necessary for resolving ancient phylogenetic relationships. But accurate phylogenetic inference requires that they are analyzed with realistic models that account for the heterogeneity in substitution patterns amongst the sites, genes and lineages. Two kinds of adjustments are frequently used: models that account for heterogeneity in amino acid frequencies at sites in proteins, and partitioned models that accommodate the heterogeneity in rates (branch lengths) among different proteins in different lineages (protein-wise heterotachy). Although partitioned and site-heterogeneous models are both widely used in isolation, their relative importance to the inference of correct phylogenies has not been carefully evaluated. We conducted several empirical analyses and a large set of simulations to compare the relative performances of partitioned models, site-heterogeneous models, and combined partitioned site heterogeneous models. In general, site-homogeneous models (partitioned or not) performed worse than site heterogeneous, except in simulations with extreme protein-wise heterotachy. Furthermore, simulations using empirically-derived realistic parameter settings showed a marked long-branch attraction (LBA) problem for analyses employing protein-wise partitioning even when the generating model included partitioning. This LBA problem results from a small sample bias compounded over many single protein alignments. In some cases, this problem was ameliorated by clustering similarly-evolving proteins together into larger partitions using the PartitionFinder method. Similar results were obtained under simulations with larger numbers of taxa or heterogeneity in simulating topologies over genes. For an empirical Microsporidia test data set, all but one tested site-heterogeneous models (with or without partitioning) obtain the correct Microsporidia+Fungi grouping, whereas site-homogenous models (with or without partitioning) did not. The single exception was the fully partitioned site-heterogeneous analysis that succumbed to the compounded small sample LBA bias. In general unless protein-wise heterotachy effects are extreme, it is more important to model site-heterogeneity than protein-wise heterotachy in phylogenomic analyses. Complete protein-wise partitioning should be avoided as it can lead to a serious LBA bias. In cases of extreme protein-wise heterotachy, approaches that cluster similarly-evolving proteins together and coupled with site-heterogeneous models work well for phylogenetic estimation.
34
Gallivanone, Francesca, Matteo Interlenghi, Daniela D’Ambrosio, Giuseppe Trifirò, and Isabella Castiglioni. "Parameters Influencing PET Imaging Features: A Phantom Study with Irregular and Heterogeneous Synthetic Lesions." Contrast Media & Molecular Imaging 2018 (September 10, 2018): 1–12. http://dx.doi.org/10.1155/2018/5324517.
Повний текст джерелаАнотація:
Aim. To evaluate reproducibility and stability of radiomic features as effects of the use of different volume segmentation methods and reconstruction settings. The potential of radiomics in really capturing the presence of heterogeneous tumor uptake and irregular shape was also investigated. Materials and Methods. An anthropomorphic phantom miming real clinical situations including synthetic lesions with irregular shape and nonuniform radiotracer uptake was used. 18F-FDG PET/CT measurements of the phantom were performed including 38 lesions of different shape, size, lesion-to-background ratio, and radiotracer uptake distribution. Different reconstruction parameters and segmentation methods were considered. COVs were calculated to quantify feature variations over the different reconstruction settings. Friedman test was applied to the values of the radiomic features obtained for the considered segmentation approaches. Two sets of test-retest measurement were acquired and the pairwise intraclass correlation coefficient was calculated. Fifty-eight morphological and statistical features were extracted from the segmented lesion volumes. A Mann–Whitney test was used to evaluate significant differences among each feature when calculated from heterogeneous versus homogeneous uptake. The significance of each radiomic feature in terms of capturing heterogeneity was evaluated also by testing correlation with gold standard indexes of heterogeneity and sphericity. Results. The choice of the segmentation method has a strong impact on the stability of radiomic features (less than 20% can be considered stable features). Reconstruction affects the estimate of radiomic features (only 26% are stable). Thirty-one radiomic features (53%) resulted to be reproducible, 11 of them are able to discriminate heterogeneity. Among these, we found a subset of 3 radiomic features strongly correlated with GS heterogeneity index that can be suggested as good features for retrospective evaluations.
35
Bagozzi, Benjamin E., and Kathleen Marchetti. "Distinguishing Occasional Abstention from Routine Indifference in Models of Vote Choice." Political Science Research and Methods 5, no. 2 (August 13, 2015): 277–94. http://dx.doi.org/10.1017/psrm.2015.42.
Повний текст джерелаАнотація:
Researchers commonly employ multinomial logit (MNL) models to explain individual-level vote choice while treating “abstention” as the baseline category. Though many view abstainers as a homogeneous group, we argue that these respondents emerge from two distinct sources. Some nonvoters are likely to be “occasional voters” who abstained from a given election owing to temporary factors, such as a distaste for all candidates running in a particular election, poor weather conditions, or other temporary circumstances. On the other hand, many nonvoters are unlikely to vote regardless of the current political climate. This latter population of “routine nonvoters” is consistently disengaged from the political process in a way that is distinct from that of occasional voters. Including both sets of nonvoters within an MNL model can lead to faulty inferences. As a solution, we propose a baseline-inflated MNL estimator that models heterogeneous populations of nonvoters probabilistically, thus accounting for the presence of routine nonvoters within models of vote choice. We demonstrate the utility of this model using replications of existing political behavior research.
36
Mäkikangas, Anne, Asko Tolvanen, Kaisa Aunola, Taru Feldt, Saija Mauno, and Ulla Kinnunen. "Multilevel Latent Profile Analysis With Covariates." Organizational Research Methods 21, no. 4 (February 22, 2018): 931–54. http://dx.doi.org/10.1177/1094428118760690.
Повний текст джерелаАнотація:
Latent profile analysis (LPA) is a person-centered method commonly used in organizational research to identify homogeneous subpopulations of employees within a heterogeneous population. However, in the case of nested data structures, such as employees nested in work departments, multilevel techniques are needed. Multilevel LPA (MLPA) enables adequate modeling of subpopulations in hierarchical data sets. MLPA enables investigation of variability in the proportions of Level 1 profiles across Level 2 units, and of Level 2 latent classes based on the proportions of Level 1 latent profiles and Level 1 ratings, and the extent to which covariates drawn from the different hierarchical levels of the data affect the probability of a membership of a particular profile. We demonstrate the use of MLPA by investigating job characteristics profiles based on the job-demand-control-support (JDCS) model using data from 1,958 university employees clustered in 78 work departments. The implications of the results for organizational research are discussed, together with several issues related to the potential of MLPA for wider application.
37
Malandra, Francesco, Alessandro Vitali, Carlo Urbinati, and Matteo Garbarino. "70 Years of Land Use/Land Cover Changes in the Apennines (Italy): A Meta-Analysis." Forests 9, no. 9 (September 8, 2018): 551. http://dx.doi.org/10.3390/f9090551.
Повний текст джерелаАнотація:
Land use science usually adopts a case study approach to investigate landscape change processes, so we considered a meta-analysis an appropriate tool for summarizing general patterns and heterogeneous findings across multiple case studies over a large geographic area. Mountain landscapes in the Apennines (Italy) have undergone significant variations in the last century due to regional and national socio-economic changes. In this work, we reviewed 51 manuscripts from different databases and examined 57 case studies. We explored heterogeneous data sets, adopting a stepwise approach to select the case studies: Step 1, a general overview of the main studies; Step 2, an analysis of the features of the study sites and of land-use/cover transitions; Step 3, a landscape pattern analysis. We standardized the processing methods to obtain a new set of homogeneous data suitable for comparative analysis. After some pre-processing of the selected paper due to the broad heterogeneity of the data, we calculated common landscape metrics ex novo. We obtained digital images used to perform automatic segmentation with eCognition Developer 64 software. Our review indicated that most case studies were in Central and Southern Italy, 83% were examined at local scale, 77% carried out change detection, but only 38% included both change detection and landscape spatial pattern analysis. The results revealed a clear trend of forest expansion (+78%) and the reduction of croplands (−49%) and grasslands (−19%). We did not find significant changes in the landscape spatial patterns.
38
Hafezi, Mohammad Hesam, Lei Liu, and Hugh Millward. "Identification of Representative Patterns of Time Use Activity Through Fuzzy C-Means Clustering." Transportation Research Record: Journal of the Transportation Research Board 2668, no. 1 (January 2017): 38–50. http://dx.doi.org/10.3141/2668-05.
Повний текст джерелаАнотація:
Analysis of the time use activity patterns of urbanites will contribute greatly to the modeling of urban transportation demands by linking activity generation and activity scheduling modules in the overall activity-based modeling framework. This paper develops a framework for novel pattern recognition modeling to identify groups of individuals with homogeneous daily activity patterns. The framework consists of four modules: initialization of the total cluster number and cluster centroids, identification of individuals with homogeneous activity patterns and grouping of them into clusters, identification of sets of representative activity patterns, and exploration of interdependencies among the attributes in each identified cluster. Numerous new machine-learning techniques, such as the fuzzy C-means clustering algorithm and the classification and regression tree classifier, are employed in the process of pattern recognition. The 24-h activity patterns are split into 288 intervals of 5-min duration. Each interval includes information on activity types, duration, start time, location, and travel mode, if applicable. Aggregated statistical evaluation and Kolmogorov–Smirnov tests are performed to determine statistical significance of clustered data. Results show a heterogeneous diversity in eight identified clusters in relation to temporal distribution and significant differences in a variety of sociodemographic variables. The insights gained from this study include important information on activities—such as activity type, start time, duration, location, and travel distance—that are essential for the scheduling phase of the activity-based model. Finally, the results of this paper are expected to be implemented within the activity-based travel demand model for Halifax, Nova Scotia.
39
Moody, Kevin, and Nick Stukan. "Embedded SIP Modules for next-GEN Heterogeneous “POWER-Devices”." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2019, DPC (January 1, 2019): 000383–407. http://dx.doi.org/10.4071/2380-4491-2019-dpc-presentation_tp1_073.
Повний текст джерелаАнотація:
In this paper will focus on the comprehension of System-in-Package (SiP) with embedded active and passive components integration will be described. Embedding of semiconductor chips into substrates provides many advantages that have been noted. It allows the smallest package form-factor with high degree of miniaturization through sequentially stacking of multiple layers containing embedded devices that are optimized for electrical performance with short and geometrically well controlled copper interconnects. In addition, the embedding gives a homogeneous mechanical environment of the chips, resulting in good reliability at system level. Furthermore, embedded technology is an excellent resolution to Power management challenges dealing with new device technologies (Si, GaS, GaN) and optimization on the thermal dissipation with improved efficiency. Embedded technology comes with many challenges in 2019, primarily design for manufacturability (DFM) and maturity. Customers are looking for better-performance capability and pricing normally that means same or lower than die free package cost (DFPC) comparison. This paper will discuss the challenges bring to market the Embedded SIP Modules for next-GEN Heterogeneous “POWER-Devices” Today, the embedded process is being developed by printed circuit board (PCB) manufacturers creating a new supply chain, bringing new players into the semiconductor industry. This new supply chain comes along with new business models. As a result of the increasing interest in implementing embedding technologies, ACCESS Semiconductors in China is committed to be a leader in the adaptation of embedding technologies, with over 10-yrs mature coreless technology and proved design rules for low profile dimensions with seamless Ti/Cu sputtering and Cu pillar interconnect giving advantages in both electrical & power performance. ACCESS Patented “Via-in-Frame” technology provides High Reliability (MSL1, PCT, BHAST) at Cost Effective in high panel utilization for HVM, using standard substrate/PCB known material sets, no need for wafer bumping/RDL, over-mold or under-fill cost adders. ACCESS Semiconductors is currently in HVM on single die 2L, and LVM on multi-devices actives/passives 4L SiP construction both platforms are driven from the power market segment. In-development on Die Last & Frameless (MeSiP) platforms utilizing hybrid technology (mSAP) and Photo Imageable Dielectric (PID) materials for cost down solutions in HVM by Q1FY2020. Also, ACCESS Semiconductors total turn-key solutions will include front-of-line (FOL) and end-of-line (EOL) capability from wafer handling, back-grinding, and dicing with KGD traceability thru the embedded chip process, frame/strip singulation, FT, marking pack & ship providing additional 30% cost reduction in the future. Here's an illustration of Embedded Technology Roadmap and Product Platforms.
40
Decaux, Olivier, Laurence Lodé, Florence Magrangeas, Catherine Charbonnel, Wilfried Gouraud, Pascal Jézéquel, Michel Attal, et al. "Prediction of Survival in Multiple Myeloma Based on Gene Expression Profiles Reveals Cell Cycle and Chromosomal Instability Signatures in High-Risk Patients and Hyperdiploid Signatures in Low-Risk Patients: A Study of the Intergroupe Francophone du Myélome." Journal of Clinical Oncology 26, no. 29 (October 10, 2008): 4798–805. http://dx.doi.org/10.1200/jco.2007.13.8545.
Повний текст джерелаАнотація:
Purpose Survival of patients with multiple myeloma is highly heterogeneous, from periods of a few weeks to more than 10 years. We used gene expression profiles of myeloma cells obtained at diagnosis to identify broadly applicable prognostic markers. Patients and Methods In a training set of 182 patients, we used supervised methods to identify individual genes associated with length of survival. A survival model was built from these genes. The validity of our model was assessed in our test set of 68 patients and in three independent cohorts comprising 853 patients with multiple myeloma. Results The 15 strongest genes associated with the length of survival were used to calculate a risk score and to stratify patients into low-risk and high-risk groups. The survival-predictor score was significantly associated with survival in both the training and test sets and in the external validation cohorts. The Kaplan-Meier estimates of rates of survival at 3 years were 90.5% (95% CI, 85.6% to 95.3%) and 47.4% (95% CI, 33.5% to 60.1%), respectively, in our patients having a low risk or high risk independently of traditional prognostic factors. High-risk patients constituted a homogeneous biologic entity characterized by the overexpression of genes involved in cell cycle progression and its surveillance, whereas low-risk patients were heterogeneous and displayed hyperdiploid signatures. Conclusion Gene expression–based survival prediction and molecular features associated with high-risk patients may be useful for developing prognostic markers and may provide basis to treat these patients with new targeted antimitotics.
41
Dong, Xin, Jingchao Ni, Wei Cheng, Zhengzhang Chen, Bo Zong, Dongjin Song, Yanchi Liu, Haifeng Chen, and Gerard De Melo. "Asymmetrical Hierarchical Networks with Attentive Interactions for Interpretable Review-Based Recommendation." Proceedings of the AAAI Conference on Artificial Intelligence 34, no. 05 (April 3, 2020): 7667–74. http://dx.doi.org/10.1609/aaai.v34i05.6268.
Повний текст джерелаАнотація:
Recently, recommender systems have been able to emit substantially improved recommendations by leveraging user-provided reviews. Existing methods typically merge all reviews of a given user (item) into a long document, and then process user and item documents in the same manner. In practice, however, these two sets of reviews are notably different: users' reviews reflect a variety of items that they have bought and are hence very heterogeneous in their topics, while an item's reviews pertain only to that single item and are thus topically homogeneous. In this work, we develop a novel neural network model that properly accounts for this important difference by means of asymmetric attentive modules. The user module learns to attend to only those signals that are relevant with respect to the target item, whereas the item module learns to extract the most salient contents with regard to properties of the item. Our multi-hierarchical paradigm accounts for the fact that neither are all reviews equally useful, nor are all sentences within each review equally pertinent. Extensive experimental results on a variety of real datasets demonstrate the effectiveness of our method.
42
Finnestad, Ragnhild. "The study of the Christianization of the Nordic countries: some reflections." Scripta Instituti Donneriani Aboensis 13 (January 1, 1990): 256–72. http://dx.doi.org/10.30674/scripta.67179.
Повний текст джерелаАнотація:
The focus of this paper is some problems that appear in the study of the transition from old Norse religion to Christianity, which requires further reflection. The problems may be said to arise from the need for clearer and more pragmatic definitions of analytical categories and, also, for more precise explications of the object of study. One of the most popular concerns of the study has been to ask whether a particular idea or custom or value is "Christian" or "old Norse". Often the question tacitly, but evidently, presupposes that "Christianity" and "old Norse religion" refer to well-defined sets of ideas, customs, and values, fixed within their respective systems. But, in the first place, Christianity did not come as a homogeneous entity to the North, but as differing versions. There are grounds for presuming that "old Norse" religion displayed a heterogeneous picture, as well. Secondly, no living religion is fixed, but is continually changing. Among the most influential factors in this dynamic process are what a religion adopts from other religions, and in this respect Christianity and old Norse religion have influenced each other over a long period of time, a fact which complicates the question of identity.
43
VEISI HASAR, Rahman, and Mohammad AHMADNEJAD. "Aspects of Aspect: Phasic and Episodic Dimensions of Verbs." Acta Linguistica Asiatica 9, no. 2 (July 30, 2019): 9–52. http://dx.doi.org/10.4312/ala.9.2.9-52.
Повний текст джерелаАнотація:
The present study sets out to analyze aspectuality and coercion in Persian from a new perspective. With regard to the transcendental aspectual distinction between perfectivity, characterized by boundedness and heterogeneity, and imperfectivity, specified by uniformity and homogeneity (Langacker, 2008), it is argued that the heterogeneity of verbs may be assessed according to their phasic and episodic variables. In other words, in contrast to homogeneous verbs, which lack any kind of boundedness, heterogeneous verbs may occur either in a bounded phasic domain or in a bounded episodic domain. Concerning phasic-episodic features, this study presents a new model of lexical aspect that can differentiate five aspectual categories. The paper also scrutinizes the combinations of different verbs with different sentential operators in order to explain various kinds of type-shifting triggered by different operators. Thereby, two procedures of phasic coercion and episodic coercion are introduced which are responsible for modifying the phasic and episodic features of verbs in order to resolve the semantic conflicts between verbs and sentential operators. These procedures modify the phasic/episodic attributes of verbs according to the viewing frames evoked by interpretative operators.
44
Swathi, Boddula, and T. I. Eldho. "Aquifer parameter and zonation structure estimation using meshless local Petrov–Galerkin method and particle swarm optimization." Journal of Hydroinformatics 20, no. 2 (December 5, 2017): 457–67. http://dx.doi.org/10.2166/hydro.2017.060.
Повний текст джерелаАнотація:
Abstract The simulation-optimization (SO) modeling approach can be effectively used for aquifer parameter estimation. In this study, a numerical approach based on meshless local Petrov–Galerkin (MLPG) method is used for groundwater flow simulation and coupled with particle swarm optimization model for optimization. The study deals with the identification of the most suitable model structure for a hypothetical heterogeneous confined aquifer from a number of alternate models using zonation method of parameter estimation. A range of alternate models starting from homogeneous to more complex model structures are considered for the zonation. Inverse modeling of different model structures is carried out based on weighted least square performance criterion. The suitable models are selected and reliability analysis ascertained by computing three parameters of composite scaled sensitivity, coefficient of variation, and confidence interval, and the best model is selected. Sensitivity of estimated parameters is investigated by considering different sets of head data involving possible measurement errors. The solutions are compared with another inverse model using the MLPG and Levenberg–Marquardt algorithm. Based on the results, it is found that the proposed methodology can be utilized in the estimation of different unknown parameters in a regional groundwater system.
45
Xi, Wanqiang, Bai Chen, Yaoyao Wang, and Feng Ju. "Type synthesis of coordinated multi-robot system based on parallel thought." Transactions of the Canadian Society for Mechanical Engineering 42, no. 2 (June 1, 2018): 164–76. http://dx.doi.org/10.1139/tcsme-2017-0053.
Повний текст джерелаАнотація:
For the synthesis of the required type about the multi-robot coordination system in industrial transportation, this paper presents a novel method in which each robot in the coordinated task is viewed as a branched chain of an equivalent parallel robot (EPR), which is converted into a problem for type synthesis of parallel robots. A theoretic method is proposed to represent the kinematic features of the mechanism’s end-effector and its position and pose in the world coordinate system. The basic concept of a robotic characteristic (C) set is given, and the corresponding algorithm is analyzed. Based on the theory of C set, the concrete steps for type synthesis of EPR are presented by analyzing the characteristics of its branched chains, and many EPR groups with end kinematic features for the C sets of the operational tasks are obtained. Then three translational (3T) operational requirements that can be extended to other degrees of freedom (DOF) are adopted, and the DOF of homogeneous and heterogeneous EPR are analyzed using screw theory. Finally the validation of the method is demonstrated by Adams, which shows that the two groups are able to complete the task.
46
Wu, Pingping, Handong Tan, Changhong Lin, Miao Peng, Huan Ma, and Zhengwen Yan. "Joint inversion of two-dimensional magnetotelluric and surface wave dispersion data with cross-gradient constraints." Geophysical Journal International 221, no. 2 (January 25, 2020): 938–50. http://dx.doi.org/10.1093/gji/ggaa045.
Повний текст джерелаАнотація:
SUMMARY Multiphysics imaging for data inversion is of growing importance in many branches of science and engineering. Cross-gradient constraint has been considered as a feasible way to reduce the non-uniqueness problem inherent in inversion process by finding geometrically consistent images from multigeophysical data. Based on OCCAM inversion algorithm, a direct inversion method of 2-D profile velocity structure with surface wave dispersion data is proposed. Then we jointly invert the profiles of magnetotelluric and surface wave dispersion data with cross-gradient constraints. Three synthetic models, including block homogeneous or heterogeneous models with consistent or inconsistent discontinuities in velocity and resistivity, are presented to gauge the performance of the joint inversion scheme. We find that owning to the complementary advantages of the two geophysical data sets, the models recovered with structure coupling constraints exhibit higher resolution in the classification of complex geologic units and settle some imaging problems caused by the separate inversion methods. Finally, a realistic velocity model from the NE Tibetan Plateau and its corresponding resistivity model calculated by empirical law are used to test the effectiveness of the joint inversion scheme in the real geological environment.
47
Abrahamsen, Morten H., and Håkan Håkansson. "Resource heterogeneity and its effects on interaction and integration in customer-supplier relationships." IMP Journal 9, no. 1 (April 13, 2015): 5–25. http://dx.doi.org/10.1108/imp-01-2015-0001.
Повний текст джерелаАнотація:
Purpose – The purpose of this paper is to study the phenomenon of customer-supplier interaction and integration from a resource perspective. In economic terms, a fish may be seen as a more or less homogeneous resource. If the herring is seen as a homogeneous resource, a market should be the best way to handle the selling and buying. However, if the herring is seen as a heterogeneous resource, a more extensive type of interaction is needed. One interesting aspect with herring is that different business actors apparently see this resource in different ways. Thus, the authors will have a mixed situation, creating possible difficulties for the actors involved. Design/methodology/approach – The authors start this study in Germany, one of the most important export markets for Norwegian herring. Today, Norwegian legislation hinders the possibility of vertical integration and cooperation at the supply side of the network. However, the industry sees opportunities for growth and integration on the marketing side. To examine this issue, the study uses a qualitative design methodology, incorporating personal in-depth interviews with selected respondents in Norway and Germany. Secondary data is also used. To analyse the data, the authors introduce five interaction and integration patterns termed pure exchange – no integration; limited interaction and integration; extensive interaction and developed integration and; indirect interaction and structural integration; and full integration. Findings – The findings suggest that there is a link between how the actors perceive herring as a resource and how they interact with counterparts. The authors find that the actors who see the resource as homogeneous have limited interaction and little or no integration, whereas the actors who see the resource as heterogeneous have a much more extensive interaction and closer ties. Originality/value – The paper is an investigation of the link between the resource heterogeneity and the patterns of customer-supplier integration.
48
Van Soest, Peter J., James B. Robertson, Mary B. Hall, and Michael C. Barry. "Klason lignin is a nutritionally heterogeneous fraction unsuitable for the prediction of forage neutral-detergent fibre digestibility in ruminants." British Journal of Nutrition 124, no. 7 (May 14, 2020): 693–700. http://dx.doi.org/10.1017/s0007114520001713.
Повний текст джерелаАнотація:
AbstractAlthough lignin has been negatively correlated with neutral-detergent fibre (NDF) digestibility (NDFD) in ruminants and used to predict potential extent of NDF digestion of forages, selection of an analysis, Klason lignin (KL) or acid-detergent lignin (ADL), to describe that the nutritionally relevant lignin has not been resolved. Dismissed as an artifact is the difference between KL and ADL (ΔL). A question is whether ΔL influences NDFD. We evaluated the relationships of ΔL, KL and ADL with NDFD in order to determine the nutritionally homogeneous or heterogeneous nature of KL. Data sets from two laboratories (DS1 and DS2) were used that included ADL, KL and in vitro NDFD at 48 h (NDFD48). DS1 contained seven C3 grasses, seventeen C4 maize forages and nineteen alfalfas, and DS2 had fifteen C3 grasses, eight C4 forages and six alfalfas. Mean ΔL was greater than ADL in C3 and C4 samples and less in alfalfas. Within forage type and laboratory, ΔL was not correlated with NDFD48 (r −0·34–0·49; all P > 0·17). ADL was more consistently correlated with NDFD48 (r −0·47–−0·95; P < 0·01–0·21) than with KL (r 0·03–−0·91; P < 0·01–0·94). ΔL as a proportion of KL was correlated with NDFD48 in C3 and C4 samples (r 0·44–0·76; P < 0·01–0·08). The differing behaviours of ΔL and ADL relative to NDFD48 indicate that KL is a nutritionally heterogeneous fraction, the behaviour of which may vary by forage type and ratios of ADL and ΔL present.
49
Saijyo, K., T. Kojima, and K. Nishiwaki. "Computational fluid dynamics analysis of the effect of mixture heterogeneity on combustion process in a premixed charge compression ignition engine." International Journal of Engine Research 6, no. 5 (October 1, 2005): 487–95. http://dx.doi.org/10.1243/146808705x30585.
Повний текст джерелаАнотація:
We analyzed the interrelationships between mixture heterogeneity and reaction in a premixed charge compression ignition (PCCI) combustion, using large eddy simulation (LES) in conjunction with a reaction kinetics model. The aim of this analysis is to find the statistical characteristics of the mixture heterogeneity in a turbulent flowfield for moderating the PCCI combustion and for increasing an output limit, which is restricted by a severe knock. Several different initial conditions of heterogeneity of an air-fuel or air-fuel-EGR gas mixture were given at the intake valve closing time by a new method, which generated statistically reasonable turbulent fluctuations in both velocity and fuel mass fraction fields. The autoignition and combustion behaviours were analysed for several different sets of the r.m.s. and the length scale of the fluctuations in the fuel mass fraction. The analyses show that the combination of a larger r.m.s. value and a longer-length scale of the fluctuations in fuel mass fraction is effective to slow the combustion in a hot flame reaction phase and to avoid knocking. The analytical results also show that the heterogeneous distribution of an EGR gas has a considerable effect in making the combustion slower, even when a fuel-air mixture is homogeneous.
50
Karim, Hesam, Mohammad Hosseini Ravandi, Zahra Zandesh, Ahmad Naserpoor, Mobin Yasini, Sharareh R Niakan Kalhori, and Elham Mousavinasab. "A unique framework for the Persian clinical guidelines: addressing an evidence-based CDSS development need." BMJ Evidence-Based Medicine 25, no. 1 (May 25, 2019): 22–26. http://dx.doi.org/10.1136/bmjebm-2019-111187.
Повний текст джерелаАнотація:
Background and aimOne of the prerequisites to develop Computerised Decision Support Systems is Clinical Practice Guidelines (CPGs) which provide a systematic aid to make complex medical decisions. In order to provide an automated CPG, it is needed to have a unique structure for the CPGs. This study aims to propose a unique framework for the Persian guidelines.Materials and methods20 Persian CPGs were selected and divided into the creation and validation sets (n=10 for each). The first group was studied independently and their headings were listed; wherever possible, the headings were merged into a new heading that was applicable to all the guidelines. The developed framework was validated by the second group of the guidelines.ResultsStudied guidelines had a very heterogeneous structure. The number of original headings was 249; they were reduced to 14 main headings with 16 subheadings in a unique developed framework. The framework is able to represent and cover 100% of the guidelines.ConclusionThe heterogeneity of guidelines was high as they were not developed based on the unique framework. The proposed framework provides a layout for designing the CPGs with a homogeneous structure. Guideline developers can use this framework to develop structured CPGs. This will facilitate the integration of the guidelines into electronic medical records as well as clinical decision support systems.