2,433,217 research outputs found
Cooperation between the {B} method and the automata theory to check the component interoperability
International audienceComponent interoperability is one of the essential issues in the component based development, since it allows the composition of reusable heterogenous components developed by different people. In this paper, we propose an approach to formally verify component interoperability at signature, semantics, and protocol levels. It is based on the use of the B formal method for specifying component interfaces and finite transition systems for specifying component protocols. The verification is done with the B theorem prover and the verification of the simulation relation between transition systems. This approach allows to decide whether two components can interoperate if assembled together and whether a component can be replaced by another component
Transcription Factor-DNA Binding Via Machine Learning Ensembles
We present ensemble methods in a machine learning (ML) framework combining
predictions from five known motif/binding site exploration algorithms. For a
given TF the ensemble starts with position weight matrices (PWM's) for the
motif, collected from the component algorithms. Using dimension reduction, we
identify significant PWM-based subspaces for analysis. Within each subspace a
machine classifier is built for identifying the TF's gene (promoter) targets
(Problem 1). These PWM-based subspaces form an ML-based sequence analysis tool.
Problem 2 (finding binding motifs) is solved by agglomerating k-mer (string)
feature PWM-based subspaces that stand out in identifying gene targets. We
approach Problem 3 (binding sites) with a novel machine learning approach that
uses promoter string features and ML importance scores in a classification
algorithm locating binding sites across the genome. For target gene
identification this method improves performance (measured by the F1 score) by
about 10 percentage points over the (a) motif scanning method and (b) the
coexpression-based association method. Top motif outperformed 5 component
algorithms as well as two other common algorithms (BEST and DEME). For
identifying individual binding sites on a benchmark cross species database
(Tompa et al., 2005) we match the best performer without much human
intervention. It also improved the performance on mammalian TFs.
The ensemble can integrate orthogonal information from different weak
learners (potentially using entirely different types of features) into a
machine learner that can perform consistently better for more TFs. The TF gene
target identification component (problem 1 above) is useful in constructing a
transcriptional regulatory network from known TF-target associations. The
ensemble is easily extendable to include more tools as well as future PWM-based
information.Comment: 33 page
A Vision-Based Vehicle Follower Navigation Using Fuzzy Logic Controller
This research presents the vision-based approach to ground vehicle follower navigation.
The system utilize fuzzy logic controller to navigate itself. There are two components
of the prototype which is the vision system component and the actuating component.
The vision system component is controlled by a microprocessor, Raspberry
Pi. The actuating component is controlled by the microcontroller, Arduino Mega. The
vision system component utilizes Camshift tracking and the illumination inconsistency
is corrected using histogram equalization. The consequent parameters obtained from
the pilot test is used to design the appropriate fuzzy membership functions and rules.
The are two type of rules tested. The first one which is method A utilized 15 rules of
fuzzy logics whereas the second method which is method B introduced three additional
hedges rules to the existing 15 rules. The results show that both methods produce desirable
results as the prototype is able to navigate itself to follow the lead vehicle with
Method B produces the best results
Reconstruction of lensing from the cosmic microwave background polarization
Gravitational lensing of the cosmic microwave background (CMB) polarization
field has been recognized as a potentially valuable probe of the cosmological
density field. We apply likelihood-based techniques to the problem of lensing
of CMB polarization and show that if the B-mode polarization is mapped, then
likelihood-based techniques allow significantly better lensing reconstruction
than is possible using the previous quadratic estimator approach. With this
method the ultimate limit to lensing reconstruction is not set by the lensed
CMB power spectrum. Second-order corrections are known to produce a curl
component of the lensing deflection field that cannot be described by a
potential; we show that this does not significantly affect the reconstruction
at noise levels greater than 0.25 microK arcmin. The reduction of the mean
squared error in the lensing reconstruction relative to the quadratic method
can be as much as a factor of two at noise levels of 1.4 microK arcmin to a
factor of ten at 0.25 microK arcmin, depending on the angular scale of
interest.Comment: matches PRD accepted version. 28 pages, 8 fig
Visual task identification and characterisation using polynomial models
Developing robust and reliable control code for autonomous mobile robots is difficult, because the interaction between a physical robot and the environment is highly complex, subject to noise and variation, and therefore partly unpredictable. This means that to date it is not possible to predict robot behaviour based on theoretical models. Instead, current methods to develop robot control
code still require a substantial trial-and-error component to the software design process. This paper proposes a method of dealing with these issues by a) establishing task-achieving sensor-motor couplings through robot training, and b) representing these couplings through transparent mathematical functions that can be used to form hypotheses
and theoretical analyses of robot behaviour. We demonstrate the viability of this approach by teaching a mobile robot to track a moving football and subsequently modelling
this task using the NARMAX system identification technique
A six-factor asset pricing model
The present study introduce the human capital component to the Fama and
French five-factor model proposing an equilibrium six-factor asset pricing
model. The study employs an aggregate of four sets of portfolios mimicking size
and industry with varying dimensions. The first set consists of three set of
six portfolios each sorted on size to B/M, size to investment, and size to
momentum. The second set comprises of five index portfolios, third, a four-set
of twenty-five portfolios each sorted on size to B/M, size to investment, size
to profitability, and size to momentum, and the final set constitute thirty
industry portfolios. To estimate the parameters of six-factor asset pricing
model for the four sets of variant portfolios, we use OLS and Generalized
method of moments based robust instrumental variables technique (IVGMM). The
results obtained from the relevance, endogeneity, overidentifying restrictions,
and the Hausman's specification, tests indicate that the parameter estimates of
the six-factor model using IVGMM are robust and performs better than the OLS
approach. The human capital component shares equally the predictive power
alongside the factors in the framework in explaining the variations in return
on portfolios. Furthermore, we assess the t-ratio of the human capital
component of each IVGMM estimates of the six-factor asset pricing model for the
four sets of variant portfolios. The t-ratio of the human capital of the
eighty-three IVGMM estimates are more than 3.00 with reference to the standard
proposed by Harvey et al. (2016). This indicates the empirical success of the
six-factor asset-pricing model in explaining the variation in asset returns
Fast and precise map-making for massively multi-detector CMB experiments
Future cosmic microwave background (CMB) polarisation experiments aim to
measure an unprecedentedly small signal - the primordial gravity wave component
of the polarisation field B-mode. To achieve this, they will analyse huge
datasets, involving years worth of time-ordered data (TOD) from massively
multi-detector focal planes. This creates the need for fast and precise methods
to complement the M-L approach in analysis pipelines. In this paper, we
investigate fast map-making methods as applied to long duration, massively
multi-detector, ground-based experiments, in the context of the search for
B-modes. We focus on two alternative map-making approaches: destriping and TOD
filtering, comparing their performance on simulated multi-detector polarisation
data. We have written an optimised, parallel destriping code, the DEStriping
CARTographer DESCART, that is generalised for massive focal planes, including
the potential effect of cross-correlated TOD 1/f noise. We also determine the
scaling of computing time for destriping as applied to a simulated full-season
data-set for a realistic experiment. We find that destriping can out-perform
filtering in estimating both the large-scale E and B-mode angular power
spectra. In particular, filtering can produce significant spurious B-mode power
via EB mixing. Whilst this can be removed, it contributes to the variance of
B-mode bandpower estimates at scales near the primordial B-mode peak. For the
experimental configuration we simulate, this has an effect on the possible
detection significance for primordial B-modes. Destriping is a viable
alternative fast method to the full M-L approach that does not cause the
problems associated with filtering, and is flexible enough to fit into both M-L
and Monte-Carlo pseudo-Cl pipelines.Comment: 16 pages, 14 figures. MNRAS accepted. Typos corrected and computing
time/memory requirement orders-of-magnitude numbers in section 4 replaced by
precise number
Charge variants characterization and release assay development for co-formulated antibodies as a combination therapy
© 2019, © 2019 The Author(s). Published with license by Taylor & Francis Group, LLC. Combination therapy is a fast-growing strategy to maximize therapeutic benefits to patients. Co-formulation of two or more therapeutic proteins has advantages over the administration of multiple medications, including reduced medication errors and convenience for patients. Characterization of co-formulated biologics can be challenging due to the high degree of similarity in the physicochemical properties of co-formulated proteins, especially at different concentrations of individual components. We present the results of a deamidation study of one monoclonal antibody component (mAb-B) in co-formulated combination antibodies (referred to as COMBO) that contain various ratios of mAb-A and mAb-B. A single deamidation site in the complementarity-determining region of mAb-B was identified as a critical quality attribute (CQA) due to its impact on biological activity. A conventional charge-based method of monitoring mAb-B deamidation presented specificity and robustness challenges, especially when mAb-B was a minor component in the COMBO, making it unsuitable for lot release and stability testing. We developed and qualified a new, quality-control-friendly, single quadrupole Dalton mass detector (QDa)–based method to monitor site-specific deamidation. Our approach can be also used as a multi-attribute method for monitoring other quality attributes in COMBO. This analytical paradigm is applicable to the identification of CQAs in combination therapeutic molecules, and to the subsequent development of a highly specific, highly sensitive, and sufficiently robust method for routine monitoring CQAs for lot release test and during stability studies
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