scholarly journals Adaptive federated filter for multi-sensor nonlinear system with cross-correlated noises

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246680
Author(s):  
Lijun Wang ◽  
Sisi Wang ◽  
Wenzhi Yang

This paper presents an adaptive approach to the federated filter for multi-sensor nonlinear systems with cross-correlations between process noise and local measurement noise. The adaptive Gaussian filter is used as the local filter of the federated filter for the first time, which overcomes the performance degradation caused by the cross-correlated noises. Two kinds of adaptive federated filters are proposed, one uses a de-correlation framework as local filter, and the subfilter of the other one is defined as a Gaussian filter with correlated noises at the same-epoch, and much effort is made to verify the theoretical equivalence of the two algorithms in the nonlinear fusion system. Simulation results show that the proposed algorithms are superior to the traditional federated filter and Gaussian filter with same-paced correlated noises, and the equivalence between the proposed algorithms and high degree cubature federated filter is also demonstrated.

Author(s):  
N. S. Gopaul ◽  
J. G. Wang ◽  
B. Hu

An image-aided inertial navigation implies that the errors of an inertial navigator are estimated via the Kalman filter using the aiding measurements derived from images. The standard Kalman filter runs under the assumption that the process noise vector and measurement noise vector are white, i.e. independent and normally distributed with zero means. However, this does not hold in the image-aided inertial navigation. In the image-aided inertial integrated navigation, the relative positions from optic-flow egomotion estimation or visual odometry are <i>pairwise</i> correlated in terms of time. It is well-known that the solution of the standard Kalman filter becomes suboptimal if the measurements are colored or time-correlated. Usually, a shaping filter is used to model timecorrelated errors. However, the commonly used shaping filter assume that the measurement noise vector at epoch <i>k</i> is not only correlated with the one from epoch <i>k</i> &ndash; 1 but also with the ones before epoch <i>k</i> &ndash; 1 . The shaping filter presented in this paper uses Cholesky factors under the assumption that the measurement noise vector is pairwise time-correlated i.e. the measurement noise are only correlated with the ones from previous epoch. Simulation results show that the new algorithm performs better than the existing algorithms and is optimal.


2012 ◽  
Vol 61 (1-6) ◽  
pp. 179-186 ◽  
Author(s):  
Elena Truta ◽  
Gabriela Vochita ◽  
Adrian Oprea ◽  
Culita Sirbu

Abstract The description of the karyotype features and idiogram in Grindelia squarrosa (Pursh) Dunal (Asteraceae), an invasive plant in Romania, are reported here for the first time. The diploid chromosome number is 2n=2x=12, in agreement with the data published for the other species of the genus. The karyomorphological data show that the complements of the studied genotypes have small chromosomes (mean chromosome length is X̅±SE=2.56±0.10 μm, and mean length of haploid complements is X̅±SE=15.33±0.69 μm, with a range of variability comprised between 12.87-17.51 μm). The karyotypes are made up of six pairs of metacentric and submetacentric chromosomes, with an identical formula of the diploid complement: KF=2n=12=8m+ 2sm + 2sm-SAT. Satellites are located on the short arms of the chromosomes of pair III. The karyotypes show a relatively high level of intra-specific uniformity as well as similar symmetry patterns (R=1.29-1.53; TF%=38.78-41.57%; AsI%=54.54-57.61%; A1 = 0.24- 0.32; A2=0.08-0.16), belonging to 1A and 2A classes of symmetry. The small size of the chromosomes, the presence of only two chromosome morphometric types, and the preponderance of metacentrics confer a relatively high degree of symmetry to the karyotypes studied.


2012 ◽  
Vol 39 (2) ◽  
pp. 217-233 ◽  
Author(s):  
J. David Archibald

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.


2018 ◽  
Vol 52 (2) ◽  
pp. 455-462 ◽  
Author(s):  
G. Ya. Doroshina ◽  
I. A. Nikolajev

Sphagnum mires on the Greater Caucasus are rare, characterized by the presence of relict plant communities of glacial age and are in a stage of degradation. The study of Sphagnum of Chefandzar and Masota mires is carried out for the first time. Seven species of Sphagnum are recorded. Their distribution and frequency within the North Caucasus are analyzed. Sphagnum contortum, S. platyphyllum, S. russowii, S. squarrosum are recorded for the first time for the study area and for the flora of North Ossetia. The other mosses found in the study area are listed.


2018 ◽  
Author(s):  
Amir Forouharfar

The paper was shaped around the pivotal question: Is SE a sound and scientific field of research? The question has given a critical tone to the paper and has also helped to bring out some of the controversial debates in the realm of SE. The paper was organized under five main discussions to be able to provide a scientific answer to the research question: (1)<b> </b>is “social entrepreneurship” an oxymoron?, (2) the characteristics of SE knowledge, (3) sources of social entrepreneurship knowledge, (4) SE knowledge: structure and limitations and (5) contributing epistemology-making concepts for SE.<b> </b>Based on the sections,<b> </b>the study relied on the relevant philosophical schools of thought in <i>Epistemology </i>(e.g. <i>Empiricism</i>, <i>Rationalism</i>, <i>Skepticism</i>, <i>Internalism</i> vs. <i>Externalism</i>,<i> Essentialism, Social Constructivism</i>, <i>Social Epistemology, etc.</i>) to discuss these controversies around SE and proposes some solutions by reviewing SE literature. Also, to determine the governing linguistic discourse in the realm of SE, which was necessary for our discussion,<i> Corpus of Contemporary American English (COCA)</i> for the first time in SE studies was used. Further, through the study, SE buzzwords which constitute SE terminology were derived and introduced to help us narrowing down and converging the thoughts in this field and demarking the epistemological boundaries of SE. The originality of the paper on one hand lies in its pioneering discussions on SE epistemology and on the other hand in paving the way for a construction of sound epistemology for SE; therefore in many cases after preparing the philosophical ground for the discussions, it went beyond the prevalent SE literature through meta-analysis to discuss the cases which were raised. The results of the study verified previously claimed embryonic pre-paradigmatic phase in SE which was far from a sound and scientific knowledge, although the scholarly endeavors are the harbingers of such a possibility in the future which calls for further mature academic discussion and development of SE knowledge by the SE academia.


Author(s):  
Caroline Durand

Al-Qusayr is located 40 km south of modern al-Wajh, roughly 7 km from the eastern Red Sea shore. This site is known since the mid-19th century, when the explorer R. Burton described it for the first time, in particular the remains of a monumental building so-called al-Qasr. In March 2016, a new survey of the site was undertaken by the al-‘Ula–al-Wajh Survey Project. This survey focused not only on al-Qasr but also on the surrounding site corresponding to the ancient settlement. A surface collection of pottery sherds revealed a striking combination of Mediterranean and Egyptian imports on one hand, and of Nabataean productions on the other hand. This material is particularly homogeneous on the chronological point of view, suggesting a rather limited occupation period for the site. Attesting contacts between Mediterranean merchants, Roman Egypt and the Nabataean kingdom, these new data allow a complete reassessment of the importance of this locality in the Red Sea trade routes during antiquity.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 492f-493
Author(s):  
Roberto F. Vieira ◽  
James E. Simon ◽  
Peter Goldsbrough ◽  
Antonio Figueira

Essential oils extracted from basil (Ocimum spp.) by steam distillation are used to flavor foods, oral products, in fragrances, and in traditional medicines. The genus Ocimum contains around 30 species native to the tropics and subtropics, with some species naturalized and/or cultivated in temperate areas. Interand intraspecific hybridization have created significant confusion in the botanical systematics of this genus. Taxonomy of basil (O. basilicum) is also complicated by the existence of numerous varieties, cultivars, and chemotypes within the species that do not differ significantly in morphology. In this study we are using RAPD markers and volatile oil composition to characterize the genetic diversity among the most economically important Ocimum species. We hypothesize that the genetic similarity revealed by molecular markers will more accurately reflect the morphological and chemical differences in Ocimum than essential oil composition per se. Preliminary research using five Ocimum species, four undetermined species, and eight varieties of O. basilicum (a total of 19 accessions) generated 107 polymorphic fragments amplified with 19 primers. RAPDs are able to discriminate between Ocimum species, but show a high degree of similarity between O. basilicum varieties. The genetic distance between nine species and among 55 accessions within the species O. americanum, O. basilicum, O. campechianum, O. × citriodorum, O. gratissimum, O. kilimandscharium, O. minimum, O. selloi, and O. tenuiflorum will be analyzed by matrix of similarity and compared to the volatile oil profile. This research will for the first time apply molecular markers to characterize the genetic diversity of Ocimum associate with volatile oil constituent.


Author(s):  
Supriya Raheja

Background: The extension of CPU schedulers with fuzzy has been ascertained better because of its unique capability of handling imprecise information. Though, other generalized forms of fuzzy can be used which can further extend the performance of the scheduler. Objectives: This paper introduces a novel approach to design an intuitionistic fuzzy inference system for CPU scheduler. Methods: The proposed inference system is implemented with a priority scheduler. The proposed scheduler has the ability to dynamically handle the impreciseness of both priority and estimated execution time. It also makes the system adaptive based on the continuous feedback. The proposed scheduler is also capable enough to schedule the tasks according to dynamically generated priority. To demonstrate the performance of proposed scheduler, a simulation environment has been implemented and the performance of proposed scheduler is compared with the other three baseline schedulers (conventional priority scheduler, fuzzy based priority scheduler and vague based priority scheduler). Results: Proposed scheduler is also compared with the shortest job first CPU scheduler as it is known to be an optimized solution for the schedulers. Conclusion: Simulation results prove the effectiveness and efficiency of intuitionistic fuzzy based priority scheduler. Moreover, it provides optimised results as its results are comparable to the results of shortest job first.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.


1980 ◽  
Vol 45 (4) ◽  
pp. 1144-1154 ◽  
Author(s):  
Miroslav Baudyš ◽  
Helena Keilová ◽  
Vladimír Kostka

To determine the primary structure of the C-terminal part of the molecule of chicken pepsinogen the tryptic, chymotryptic and thermolytic digest of the protein were investigated and peptides derived from this region were sought. These peptides permitted the following 21-residue C-terminal sequence to be determined: ...Ile-Arg-Glu-Tyr-Tyr-Val-Ile-Phe-Asp-Arg-Ala-Asn-Asn-Lys-Val-Gly-Leu-Ser-Pro-Leu-Ser.COOH. A comparison of this structure with the C-terminal sequential regions of the other acid proteases shows a high degree of homology between chicken pepsinogen and these proteases (e.g., the degree of homology with respect to hog pepsinogen and calf prochymosin is about 66%). Additional tryptic peptides, derived from the N-terminal part of the zymogen molecule whose amino acid sequence has been reported before, were also obtained in this study. This sequence was extended by two residues using an overlapping peptide. An ancillary result of this study was the isolation of tryptic peptides derived from other regions of the zymogen molecule.


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