scholarly journals Building heterogeneous ensembles by pooling homogeneous ensembles

Author(s):  
Maryam Sabzevari ◽  
Gonzalo Martínez-Muñoz ◽  
Alberto Suárez

AbstractHeterogeneous ensembles consist of predictors of different types, which are likely to have different biases. If these biases are complementary, the combination of their decisions is beneficial and could be superior to homogeneous ensembles. In this paper, a family of heterogeneous ensembles is built by pooling classifiers from M homogeneous ensembles of different types of size T. Depending on the fraction of base classifiers of each type, a particular heterogeneous combination in this family is represented by a point in a regular simplex in M dimensions. The M vertices of this simplex represent the different homogeneous ensembles. A displacement away from one of these vertices effects a smooth transformation of the corresponding homogeneous ensemble into a heterogeneous one. The optimal composition of such heterogeneous ensemble can be determined using cross-validation or, if bootstrap samples are used to build the individual classifiers, out-of-bag data. The proposed heterogeneous ensemble building strategy, composed of neural networks, SVMs, and random trees (i.e. from a standard random forest), is analyzed in a comprehensive empirical analysis and compared to a benchmark of other heterogeneous and homogeneous ensembles. The achieved results illustrate the gains that can be achieved by the proposed ensemble creation method with respect to both homogeneous ensembles and to the tested heterogeneous building strategy at a fraction of the training cost.

2021 ◽  
pp. 1-30
Author(s):  
Yong Pang ◽  
Yitang Wang ◽  
Wei Sun ◽  
Xueguan Song

Abstract The ensemble of surrogate models is increasingly implemented in practice for its more flexibility and robustness compared to the individual surrogate models. In this work, a novel pointwise ensemble of surrogate models named the optimization-based two-layer pointwise ensemble of surrogate model (OTL-PEM) is proposed. In the OTL-PEM, the framework of two-layer surrogate models is defined, where the data-surrogate models containing different types of individual surrogate models are to fit the given dataset, while the weight-surrogate models are modeled based on the cross-validation errors aiming to fit the pointwise weights of different individual surrogate models. To avoid the negative influence of the poor individual surrogate models, the model selection problem is transformed into several optimization problems which can be solved easily by the mature optimization algorithm to eliminate the globally poor surrogate models. In addition, the optimization space is extracted to alleviating the predictive instability caused by the extrapolation of the weight-surrogate models. Forty test functions are used to select the appropriate hyperparameters of the OTL-PEM, and to evaluate the performance of the OTL-PEM. The results indicate that the OTL-PEM can provide more accurate and robust approximation performance compared with individual surrogate models as well as other ensembles of surrogate models.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3874
Author(s):  
Dominika Veselinyová ◽  
Jana Mašlanková ◽  
Katarina Kalinová ◽  
Helena Mičková ◽  
Mária Mareková ◽  
...  

We are experiencing rapid progress in all types of imaging techniques used in the detection of various numbers and types of mutation. In situ hybridization (ISH) is the primary technique for the discovery of mutation agents, which are presented in a variety of cells. The ability of DNA to complementary bind is one of the main principles in every method used in ISH. From the first use of in situ techniques, scientists paid attention to the improvement of the probe design and detection, to enhance the fluorescent signal intensity and inhibition of cross-hybrid presence. This article discusses the individual types and modifications, and is focused on explaining the principles and limitations of ISH division on different types of probes. The article describes a design of probes for individual types of in situ hybridization (ISH), as well as the gradual combination of several laboratory procedures to achieve the highest possible sensitivity and to prevent undesirable events accompanying hybridization. The article also informs about applications of the methodology, in practice and in research, to detect cell to cell communication and principles of gene silencing, process of oncogenesis, and many other unknown processes taking place in organisms at the DNA/RNA level.


1923 ◽  
Vol 17 (2) ◽  
pp. 204-215
Author(s):  
Raymond G. Gettell

In the introduction to his readings in political philosophy, Professor Coker says, “since the time of Plato there has been, in every philosophic age, some inquiry as to the justification of political organization in general, as to the relative merits of different political forms, and as to the appropriate position and privileges of the individual as master, member, or subject of the political order of society. Why do we have political organization? What in our present condition do we owe to it? What future benefits may we properly expect to derive from it? Are its purposes characteristically manifold and changing, or are they ultimately reducible to a few limited objects or to some single end? What is its best form? Who should control it? What is its proper relation to the ideas and sentiments of the community at its basis? What spheres of individual and social life is it incompetent to enter? Philosophers and publicists of various types have sought to answer these questions in abstract terms.”If an analysis be made of the questions with which political thought has been concerned, it is found that emphasis was placed at various periods upon widely different types of problems. In the medieval period political controversy centered in the contest for supremacy between spiritual and temporal authorities; in the seventeenth and eighteenth centuries, the dominant interest was in the contest between monarchic and democratic theories of political organization; at present, the extent of state activities has come into prominence, and the connection between political and economic interests is especially close. Besides, political conditions have changed so greatly from age to age that the same problem had quite different meanings at different periods.


Author(s):  
A. Yu. Bovsunivska A. Yu.

The article is devoted to the study of pragmatic aspects of the use of phraseology in the textual space of Carlos Ruiz Safón’s novel «Prisoner of Heaven». One of the defining features of the individual style of this well-known modern Spanish writer is the metaphoricity and figuration of aristic expression, the saturation of the text with phraseological units that play a significant role in creating a pragmatic charge of the work of art. Along with general linguistic phraseological units, which include commonly-used vocabulary, the author uses dialectal and authorial phraseological units, which is a feature of his individual style. All three designated groups of phraseological units mostly reflect the negative psychophysical and emotional state of the characters. The author uses dialectal, individually-authorial and modified phraseological units, which is a feature of his individual style. It is determined that transformation is one of the most productive and most effective ways to update linguistic means in works of art. Author’s modification of FU leads to a change in the semantics and structure of expression, gives it a more expressive or emotional coloring. Transformed phraseology is limited to individual usage and is subject to the context of the work. Modified FUs in the Zafón’s artistic space acquire certain aesthetic and artistic qualities. Their modification is mainly to create the desired stylistic effect – to achieve emotional or expressive expression, which increases the reader’s interest, focuses on the content, issues of the work, as well as reveals the potential expressive potential of the Spanish language. In the transformed FUs, not just a new meaning is traced, but a combination of the well-known and the occasional. The unique combination of different types of phraseological units in the novel is considered a manifestation of individual style and makes a representation of the individually-authorial linguistic picture of the world more expressive.


2021 ◽  
Vol 11 (1) ◽  
pp. 29-33
Author(s):  
Anjana Karmacharya ◽  
Dashrath Kafle ◽  
Ram Bhakta Adhikari ◽  
Nirjalla Malla

Introduction: Retainers are used after all orthodontic treatment, to prevent or minimize relapse and recurrence. Among various retainers used, Hawley retainer and ‘invisible’ retainers are the most common. Most of the orthodontists favored permanent retention. It is obvious that the retention procedures are variable and depended largely on personal preferences, and there does not seem to be any consistent pattern in the application of retention methodologies. The  purpose of this study was to survey the retention protocols among orthodontists in Nepal. Materials and Method: The complete lists of the names and addresses of orthodontists in Nepal was obtained from the ODOAN. The questionnaire was sent to them which consisted of multiple-choice questions and short answer, related to background information of the individual orthodontist, retention use in general, the frequency of different types of bonded or removable retainers that are used, the retention protocol, the type of retainer used in specific situation. All statistical analyses were performed using the Statistical Package for Social Sciences (SPSS), version 12.0.1 (SPSS Inc, Chicago, Illinois, USA) Result: The survey questionnaires were completed by 90.42% of the 94 orthodontists of Nepal, 58.8% males and 41.2% females with a mean age of 36.7 years. Most of the orthodontists used a clear (vacuum) retainer (80%) in the maxilla and fixed bonded retainer in the mandible. Most of them prefer the use of retainer for a continuous 24 hours except during eating and brushing for 6 months to 1 year (56.5%) and if possible, for 1 to 2 years (28.2%). Conclusion: Majority of Nepalese orthodontists provide vacuum formed retainer on maxillary arch and bonded retainer in mandibular arch. There is no specific consensus on other type of retainers, duration of wear and follow up visits which is affected by various other factors.


2021 ◽  
Vol 8 (4) ◽  
pp. 258-261
Author(s):  
Bedanta Sarma ◽  
Shreemanta Kumar Dash ◽  
Pankaj Suresh Ghormade

Work related fall from height many a times causes fatal injuries and death amongst working in various construction sites. It leads to different types of fatal bodily injuries including spinal injuries causing economic burden to the family. Although, they have been provided with protective gears and proper training for its use; it has been observed that workers are not using these in a proper ways. They eventually met with accidents which can easily be prevented. Accidental compression of neck by safety harness following fall from height has rarely been described leading to death of the individual. A case was brought for autopsy following accidental compression of neck structure causing fracture of cervical spine and transaction of spinal cord. In this paper, the case has been described with its autopsy findings.


Author(s):  
Yasin Görmez ◽  
◽  
Yunus E. Işık ◽  
Mustafa Temiz ◽  
Zafer Aydın

Sentiment analysis is the process of determining the attitude or the emotional state of a text automatically. Many algorithms are proposed for this task including ensemble methods, which have the potential to decrease error rates of the individual base learners considerably. In many machine learning tasks and especially in sentiment analysis, extracting informative features is as important as developing sophisticated classifiers. In this study, a stacked ensemble method is proposed for sentiment analysis, which systematically combines six feature extraction methods and three classifiers. The proposed method obtains cross-validation accuracies of 89.6%, 90.7% and 67.2% on large movie, Turkish movie and SemEval-2017 datasets, respectively, outperforming the other classifiers. The accuracy improvements are shown to be statistically significant at the 99% confidence level by performing a Z-test.


Author(s):  
Angga Rahagiyanto

Indonesian: Indonesian SIBI has been widely reviewed by researchers using different types of cameras and sensors. The ultimate goal is to produce a strong, fast and accurate movement recognition process. One that supports talk of movement using sensors on the MYO Armband tool. This paper explains how to use raw data generated from the MYO Armband sensor and extract integration so that it can be used to facilitate complete hand, arm and combination movements in the SIBI sign language dictionary. MYO armband uses five sensors: accelerometer, gyroscope, orientation, euler-orientation and EMG. Each sensor produces data that is different in scale and size. This requires a process to make the data uniform. This study uses the min-max method to normalize any data on the MYO Armband sensor and the Moment Invariant method to extract the vector features of hand movements. Testing is done using sign language Movement statistics both dynamic signals. Testing is done using cross validation.


Author(s):  
Liliana Cimpoies ◽  
Elena Semionova

Abstract For Moldova’s agriculture are characterized the existence of many small family farms and only a small number of corporate holdings (limited liabilities companies, agricultural production cooperatives etc). Most of individual farms, small by size produce only for own family consumption and cannot find their way to the market place. The accentuated poverty makes rural economy to flow more and more to a natural subsistence economy, isolating itself from the market economy. The goal of this paper is to delimitate different types of farms based on selected indicators and to appreciate their level of development. Differences in farms levels of development are appreciated through cluster analysis. The research includes the analysis of farms survey data. This research was carried as a part of the Academy of Sciences project “Sustainable rural development in Republic of Moldova in the context of EU accession”. In the project were surveyed 938 individual farms from nine districts across the country. As a result, we distinguish three types of farms: natural, family and market household. The cluster analysis allows to characterize the farms level development, to determine the main priority directions, and to elaborate measures for the individual farms further sustainable development.


Author(s):  
Nico Wunderling ◽  
Jonathan Krönke ◽  
Valentin Wohlfarth ◽  
Jan Kohler ◽  
Jobst Heitzig ◽  
...  

AbstractTipping elements occur in various systems such as in socio-economics, ecology and the climate system. In many cases, the individual tipping elements are not independent of each other, but they interact across scales in time and space. To model systems of interacting tipping elements, we here introduce the PyCascades open source software package for studying interacting tipping elements (10.5281/zenodo.4153102). PyCascades is an object-oriented and easily extendable package written in the programming language Python. It allows for investigating under which conditions potentially dangerous cascades can emerge between interacting dynamical systems, with a focus on tipping elements. With PyCascades it is possible to use different types of tipping elements such as double-fold and Hopf types and interactions between them. PyCascades can be applied to arbitrary complex network structures and has recently been extended to stochastic dynamical systems. This paper provides an overview of the functionality of PyCascades by introducing the basic concepts and the methodology behind it. In the end, three examples are discussed, showing three different applications of the software package. First, the moisture recycling network of the Amazon rainforest is investigated. Second, a model of interacting Earth system tipping elements is discussed. And third, the PyCascades modelling framework is applied to a global trade network.


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