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Search Results: 1 - 10 of 1847 matches for " Mathias "
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Aggregating Density Estimators: An Empirical Study  [PDF]
Mathias Bourel, Badih Ghattas
Open Journal of Statistics (OJS) , 2013, DOI: 10.4236/ojs.2013.35040

Density estimation methods based on aggregating several estimators are described and compared over several simulation models. We show that aggregation gives rise in general to better estimators than simple methods like histograms or kernel density estimators. We suggest three new simple algorithms which aggregate histograms and compare very well to all the existing methods.

Calibrating Remotely Sensed Ocean Chlorophyll Data: An Application of the Blending Technique in Three Dimensions (3D)  [PDF]
Mathias A. Onabid
Open Journal of Marine Science (OJMS) , 2017, DOI: 10.4236/ojms.2017.71014
Abstract: In this article, the extension to three dimensions (3D) of the blending technique that has been widely used in two dimensions (2D) to calibrate ocean chlorophyll is presented. The results thus obtained revealed a very high degree of efficiency when predicting observed values of ocean chlorophyll. The mean squared difference between the predicted and observed values of ocean chlorophyll when 3D technique was used fell far below the tolerance level which was set to the difference between satellite and observed in-situ values. The resulting blended field did not only provide better predictions of the in situ observations in areas where bottle samples cannot be obtained but also provided a smooth variation of the distribution of ocean chlorophyll throughout the year. An added advantage is its computational efficiency since data that would have been treated at least four times would be treated only once. With the advent of these results, it is believed that the modelling of the ocean life cycle will become more realistic.
RETRACTED: Competitiveness Evaluation of West Africa Coastal Countries Ports: Structure Conduct Performance Approch  [PDF]
Brou Mathias Allate
Open Journal of Applied Sciences (OJAppS) , 2018, DOI: 10.4236/ojapps.2018.89029

Short Retraction Notice

The paper does not meet the standards of \"Open Journal of Applied Sciences\".

This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused.

Editor guiding this retraction: Prof. A. C. Matin and Prof. Harry E. Ruda (EiC of OJAppS).

Hinterland Intermodal Freight Flow Optimization for Ports Competition Evidence of West Africa ECOWAS Region  [PDF]
Brou Mathias Allate
Open Journal of Applied Sciences (OJAppS) , 2019, DOI: 10.4236/ojapps.2019.94018
Abstract: Major problem considered in this study was the intermodal routing problem of regional freight transportation in West Africa ECOWAS (Economic Community Of West Africa States), which can be defined as the problem of determining the freight flow quantity, the transportation mode in each transit corridor while satisfying the freight demand at each West Africa transit country (Mali, Burkina Faso and Niger). The objective was to minimize in land transportation costs. In order to solve optimally and represent the problem, this research employed a linear programming model. The model was solved using Lingo Mathematic Application. The model results showed that port oriented freight logistics in west Africa ECOWAS region do not flow along optimal path and such incur longer time and higher logistics cost than is geographically necessary.
Terminal Location Models for Intermodal Transport Network Optimization  [PDF]
Brou Mathias Allate
Open Journal of Applied Sciences (OJAppS) , 2019, DOI: 10.4236/ojapps.2019.95025
Abstract: Since rail-road transport uses road and rail networks and requires the transshipment infrastructures at the terminals, its competitiveness depends not only on the costs but also on the location of these terminals. This paper focused on providing a methodology for determining the optimal locations for intermodal freight transportation terminals in consolidation network. The goal is to minimize total costs in order to increase the efficiency of the transportation system. This paper also has allowed us to have an overview of the methods and models that exist for solving the problem of intermodal and terminal locating.
Rail-Road Hinterland Intermodal Terminal Location in West Africa Region—Case Study of Corridor Port of Abidjan to Ouagadougou-Bamako  [PDF]
Brou Mathias Allate
Open Journal of Applied Sciences (OJAppS) , 2019, DOI: 10.4236/ojapps.2019.94021
Abstract: Efficient and effective movement of goods is very critical in today’s competitive environment especially for developing countries suffering from crippling logistics costs which limit their competitive ability in the global economy. Putting in place an optimal logistics network design offers great potential for logistics cost reduction and service quality improvement [1]. Therefore, this paper presents a model for effective integration of inland intermodal terminal into logistics network. The model simultaneously determines the number and location of inland terminals in network that minimize the total cost of freight flow to hinterland. The model uses Abidjan port in Cote d’Ivoire as the case study for solving numeric examples. The problem will be formulated in the case of a rail-road network where post-routing is done by road and rail link between terminal. We present a linear optimization model which is implemented using LINGO Mathematical Modeling Language.
Protein kinase CK2 in the ER stress response  [PDF]
Claudia G?tz, Mathias Montenarh
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.33A001
Abstract: The endoplasmic reticulum is the central organelle within a eukaryotic cell where newly synthesized proteins are processed and properly folded. An excess of unfolded or mis-folded proteins induces ER stress signalling pathways. Usually this means a pro-survival strategy for the cell, whereas under extended stress conditions the ER stress signalling pathways have a pro-apoptotic function. CK2 plays a key role in the regulation of the pro-survival as well as the proapoptotic ER stress signalling by directly modulating the activities of members of the ER stress signalling pathways by phosphorylation, regulating the expression of the key factors of the signalling pathways or binding to regulator proteins. The present review will summarize the state of the art in this new emerging field.
Modeling Ocean Chlorophyll Distributions by Penalizing the Blending Technique  [PDF]
Mathias A. Onabid, Simon Wood
Open Journal of Marine Science (OJMS) , 2014, DOI: 10.4236/ojms.2014.41004

Disparities between the in situ and satellite values at the positions where in situ values are obtained have been the main handicap to the smooth modeling of the distribution of ocean chlorophyll. The blending technique and the thin plate regression spline have so far been the main methods used in an attempt to calibrate ocean chlorophyll at positions where the in situ field could not provide value. In this paper, a combination of the two techniques has been used in order to provide improved and reliable estimates from the satellite field. The thin plate regression spline is applied to the blending technique by imposing a penalty on the differences between the satellite and in situ fields at positions where they both have observations. The objective of maximizing the use of the satellite field for prediction was outstanding in a validation study where the penalized blending method showed a remarkable improvement in its estimation potentials. It is hoped that most analysis on primary productivity and management in the ocean environment will be greatly affected by this result, since chlorophyll is one of the most important components in the formation of the ocean life cycle.

Estimating Ocean Chlorophyll Using the Penalized Three Dimensional (3D) Blending Technique  [PDF]
Mathias A. Onabid, Simon Wood
Open Journal of Marine Science (OJMS) , 2018, DOI: 10.4236/ojms.2018.83021
The Thin Plate Regression Spline (TPRS) was introduced as a means of smoothing off the differences between the satellite and in-situ observations during the two dimensional (2D) blending process in an attempt to calibrate ocean chlorophyll. The result was a remarkable improvement on the predictive capabilities of the penalized model making use of the satellite observation. In addition, the blending process has been extended to three dimensions (3D) since it is believed that most physical systems exist in the three dimensions (3D). In this article, an attempt to obtain more reliable and accurate predictions of ocean chlorophyll by extending the penalization process to three dimensional (3D) blending is presented. Penalty matrices were computed using the integrated least squares (ILS) and integrated squared derivative (ISD). Results obtained using the integrated least squares were not encouraging, but those obtained using the integrated squared derivative showed a reasonable improvement in predicting ocean chlorophyll especially where the validation datum was surrounded by available data from the satellite data set, however, the process appeared computationally expensive and the results matched the other methods on a general scale. In both case, the procedure for implementing the penalization process in three dimensional blending when penalty matrices were calculated using the two techniques has been well established and can be used in any similar three dimensional problem when it becomes necessary.
A new era for proteomics research?
Mathias Uhlen
Genome Biology , 2008, DOI: 10.1186/gb-2008-9-11-325
Abstract: The human genome sequence provided information on the protein-encoding genes that are expressed in the hundreds of cell types that make up the human body. The next step forward is to use the information from genomics research for a systematic study of the human proteome. At the recent Human Proteome Organization (HUPO) conference in Amsterdam, various approaches to such studies were discussed. Topics covered the use of proteomics to study biology in humans and model organisms, including investigations aimed at increasing the understanding of cellular pathways, the biology of stem cells, and subcellular organization.The state of the art in mass spectrometry was addressed in several keynote lectures. Refined instrumentation and more advanced software for analysis means that whole-proteome coverage for model organisms in a single experiment can now be envisaged and relatively low-abundance mammalian proteins can be detected. Ruedi Aebersold (ETH, Zurich, Switzerland and ISB, Seattle, USA) described the identification of 'proteotypic peptides' - protein fragments that are detectable in mass spectrometry - and pointed out that a vision for the future might be to identify and publish such peptides for all human proteins and to make these publicly available through web portals such as the Peptide Atlas http://www.peptideatlas.org webcite. Matthias Mann (Max Planck Institute of Biochemistry, Martinsried, Germany) focused on the advantages of using stable isotopes to achieve higher accuracy in quantitative measurements of proteins. He described the use of SILAC (stable isotope labeling with amino acids in cell culture) for the study of proteins in cell lines and model organisms such as rat and mouse. By combining kinase-specific affinity purification and quantitative mass spectrometry, more than 1,000 phosphorylation sites on human protein kinases were identified, and interestingly, more than half of these were upregulated during mitosis in human cancer cells.The use of anti
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