scholarly journals Centroid-Based Clustering with αβ-Divergences

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 196 ◽  
Author(s):  
Auxiliadora Sarmiento ◽  
Irene Fondón ◽  
Iván Durán-Díaz ◽  
Sergio Cruces

Centroid-based clustering is a widely used technique within unsupervised learning algorithms in many research fields. The success of any centroid-based clustering relies on the choice of the similarity measure under use. In recent years, most studies focused on including several divergence measures in the traditional hard k-means algorithm. In this article, we consider the problem of centroid-based clustering using the family of α β -divergences, which is governed by two parameters, α and β . We propose a new iterative algorithm, α β -k-means, giving closed-form solutions for the computation of the sided centroids. The algorithm can be fine-tuned by means of this pair of values, yielding a wide range of the most frequently used divergences. Moreover, it is guaranteed to converge to local minima for a wide range of values of the pair ( α , β ). Our theoretical contribution has been validated by several experiments performed with synthetic and real data and exploring the ( α , β ) plane. The numerical results obtained confirm the quality of the algorithm and its suitability to be used in several practical applications.

2020 ◽  
Vol 1 (10(79)) ◽  
pp. 12-18
Author(s):  
G. Bubyreva

The existing legislation determines the education as "an integral and focused process of teaching and upbringing, which represents a socially important value and shall be implemented so as to meet the interests of the individual, the family, the society and the state". However, even in this part, the meaning of the notion ‘socially significant benefit is not specified and allows for a wide range of interpretation [2]. Yet the more inconcrete is the answer to the question – "who and how should determine the interests of the individual, the family and even the state?" The national doctrine of education in the Russian Federation, which determined the goals of teaching and upbringing, the ways to attain them by means of the state policy regulating the field of education, the target achievements of the development of the educational system for the period up to 2025, approved by the Decree of the Government of the Russian Federation of October 4, 2000 #751, was abrogated by the Decree of the Government of the Russian Federation of March 29, 2014 #245 [7]. The new doctrine has not been developed so far. The RAE Academician A.B. Khutorsky believes that the absence of the national doctrine of education presents a threat to national security and a violation of the right of citizens to quality education. Accordingly, the teacher has to solve the problem of achieving the harmony of interests of the individual, the family, the society and the government on their own, which, however, judging by the officially published results, is the task that exceeds the abilities of the participants of the educational process.  The particular concern about the results of the patriotic upbringing served as a basis for the legislative initiative of the RF President V. V. Putin, who introduced the project of an amendment to the Law of RF "About Education of the Russian Federation" to the State Duma in 2020, regarding the quality of patriotic upbringing [3]. Patriotism, considered by the President of RF V. V. Putin as the only possible idea to unite the nation is "THE FEELING OF LOVE OF THE MOTHERLAND" and the readiness for every sacrifice and heroic deed for the sake of the interests of your Motherland. However, the practicing educators experience shortfalls in efficient methodologies of patriotic upbringing, which should let them bring up citizens, loving their Motherland more than themselves. The article is dedicated to solution to this problem based on the Value-sense paradigm of upbringing educational dynasty of the Kurbatovs [15].


1985 ◽  
Vol 16 (1) ◽  
pp. 1-10 ◽  
Author(s):  
V. P. Singh ◽  
C. Corradini ◽  
F. Melone

The geomorphological instantaneous unit hydrograph (IUH) proposed by Gupta et al. (1980) was compared with the IUH derived by commonly used time-area and Nash methods. This comparison was performed by analyzing the effective rainfall-direct runoff relationship for four large basins in Central Italy ranging in area from 934 to 4,147 km2. The Nash method was found to be the most accurate of the three methods. The geomorphological method, with only one parameter estimated in advance from the observed data, was found to be little less accurate than the Nash method which has two parameters determined from observations. Furthermore, if the geomorphological and Nash methods employed the same information represented by basin lag, then they produced similar accuracy provided the other Nash parameter, expressed by the product of peak flow and time to peak, was empirically assessed within a wide range of values. It was concluded that it was more appropriate to use the geomorphological method for ungaged basins and the Nash method for gaged basins.


2021 ◽  
pp. 1-3
Author(s):  
Uwe Gieler

<b>Background</b>: Hidradenitis suppurativa is a debilitating disease related to a great psychosocial burden in affected patients and subsequently also people around them. Patients’ partners as caregivers may indirectly experience wide range of devastating effects of the disease on their emotional and social life. <b>Objective:</b> The purpose of this study was to determine the QoL impairment in HS patients’ partners and to identify its aspects that are affected the most. Correlation between QoL burden and disease severity, duration, sex, age and smoking was also assessed. <b>Methods:</b> A total of 50 HS sufferers were assessed according to disease severity and their partners’ QoL was determined using the Family Dermatology Life Quality Index questionnaire. <b>Results:</b> The mean FDLQI for patients’ partners was 8.7 ± 6.8 points, indicating generally a moderate effect of HS on their life. Quality of partners’ life correlated significantly with disease severity but no correlation was found according to other factors. <b>Conclusion:</b> Hidradenitis suppurativa is a highly psychologically devastating disease not only for patients but also for their partners. It occurred to diminish partners’ QoL mostly by increasing daily expenditure but also other problems were often reported. Clinicians should be aware of these psychosocial implications, in order to provide optimal therapy of HS affected families by a multidisciplinary specialized management addressing both, patients and their cohabitants simultaneously.


2015 ◽  
Vol 5 (3) ◽  
pp. 188-200 ◽  
Author(s):  
Maria Ioannou ◽  
Laura Hammond ◽  
Olivia Simpson

Purpose – The purpose of this paper is to explore the potential for developing a model for differentiating school shooters based on their characteristics (or risk factors) before the attack took place. Design/methodology/approach – Data on 40 school shootings was compiled from the National School Safety Center’s Report on School Associated Violent Deaths and media accounts. Content analysis of the cases produced a set of 18 variables relating to offenders’ characteristics (or risk factors). Data were subjected to Smallest Space Analysis (SSA), a non-metric multidimensional scaling procedure. Findings – Results revealed three distinct themes: Disturbed School Shooter, Rejected School Shooter and Criminal School Shooter. Further analysis identified links between these themes with the family background of the offender. Research limitations/implications – These findings have both significant theoretical implications in the understanding of school shooters and the crime in general. They offer potential for practical applications in terms of prevention and intervention strategies. A key limitation relates to the quality of data. Originality/value – This is the first study to develop a model for differentiating school shooter characteristics.


2021 ◽  
Author(s):  
J Tondeur ◽  
D Petko ◽  
R Christensen ◽  
K Drossel ◽  
Anne Starkey ◽  
...  

© 2021, Association for Educational Communications and Technology. In order to effectively use technology in education, appropriate conceptual understandings are needed to guide the integration process. Today, there is a wide range of conceptual models that are developed and used in research and/or practice focusing on educational technology integration. Conceptual models are of relevance as they can bridge theory with practical applications. Today, there are a wide range of conceptual models are developed and used in research and/or practice focusing on educational technology integration. These models can be seen as simplified versions of theories for practical application or as condensed wisdoms of practice that need to be further investigated theoretically and empirically. However, there is insufficient agreement on the dimensions and criteria used to judge the quality of conceptual models in educational technology. Therefore, the main goals of this article are to: (1) develop criteria to assess the quality and scope of conceptual models and (2) identify and compare exemplary models for technology integration in educational settings along with these quality criteria. The resulting five criteria from this investigation provide the means to effectively evaluate the quality and scope of conceptual models focused on technology integration while providing additional insight into applying these models in research and practice.


2018 ◽  
Vol 115 (38) ◽  
pp. 9351-9358 ◽  
Author(s):  
Robert M. Yarrington ◽  
Surbhi Verma ◽  
Shaina Schwartz ◽  
Jonathan K. Trautman ◽  
Dana Carroll

Genome editing with CRISPR-Cas nucleases has been applied successfully to a wide range of cells and organisms. There is, however, considerable variation in the efficiency of cleavage and outcomes at different genomic targets, even within the same cell type. Some of this variability is likely due to the inherent quality of the interaction between the guide RNA and the target sequence, but some may also reflect the relative accessibility of the target. We investigated the influence of chromatin structure, particularly the presence or absence of nucleosomes, on cleavage by the Streptococcus pyogenes Cas9 protein. At multiple target sequences in two promoters in the yeast genome, we find that Cas9 cleavage is strongly inhibited when the DNA target is within a nucleosome. This inhibition is relieved when nucleosomes are depleted. Remarkably, the same is not true of zinc-finger nucleases (ZFNs), which cleave equally well at nucleosome-occupied and nucleosome-depleted sites. These results have implications for the choice of specific targets for genome editing, both in research and in clinical and other practical applications.


1969 ◽  
Vol 36 (4) ◽  
pp. 715-722
Author(s):  
E. M. Sparrow ◽  
H. S. Yu ◽  
T. S. Lundgren

The effect of actively participating bounding surfaces on the free molecule flow through a slit or an annular orifice situated in a wall separating two regions of different pressure is analyzed. The flow through the slit or orifice depends on the distributions of the flux of mass leaving the bounding surfaces. These distributions are found by formulating and solving pairs of integral equations. In the case of the slit, the integral equations are formulated by employing kinetic theory methods, while for the annular orifice it was found advantageous to use the techniques of radiative transfer. In addition to exact solutions, closed-form solutions based on an approximate model are derived. Results are presented for a wide range of values of the relevant geometrical parameters.


Author(s):  
M. Bagheri ◽  
Ali Ebrahimnejad ◽  
S. Razavyan ◽  
F. Hosseinzadeh Lotfi ◽  
N. Malekmohammadi

AbstractThe shortest path problem (SPP) is a special network structured linear programming problem that appears in a wide range of applications. Classical SPPs consider only one objective in the networks while some or all of the multiple, conflicting and incommensurate objectives such as optimization of cost, profit, time, distance, risk, and quality of service may arise together in real-world applications. These types of SPPs are known as the multi-objective shortest path problem (MOSPP) and can be solved with the existing various approaches. This paper develops a Data Envelopment Analysis (DEA)-based approach to solve the MOSPP with fuzzy parameters (FMOSPP) to account for real situations where input–output data include uncertainty of triangular membership form. This approach to make a connection between the MOSPP and DEA is more flexible to deal with real practical applications. To this end, each arc in a FMOSPP is considered as a decision-making unit with multiple fuzzy inputs and outputs. Then two fuzzy efficiency scores are obtained corresponding to each arc. These fuzzy efficiency scores are combined to define a unique fuzzy relative efficiency. Hence, the FMOSPP is converted into a single objective Fuzzy Shortest Path Problem (FSPP) that can be solved using existing FSPP algorithms.


2021 ◽  
Author(s):  
J Tondeur ◽  
D Petko ◽  
R Christensen ◽  
K Drossel ◽  
Anne Starkey ◽  
...  

© 2021, Association for Educational Communications and Technology. In order to effectively use technology in education, appropriate conceptual understandings are needed to guide the integration process. Today, there is a wide range of conceptual models that are developed and used in research and/or practice focusing on educational technology integration. Conceptual models are of relevance as they can bridge theory with practical applications. Today, there are a wide range of conceptual models are developed and used in research and/or practice focusing on educational technology integration. These models can be seen as simplified versions of theories for practical application or as condensed wisdoms of practice that need to be further investigated theoretically and empirically. However, there is insufficient agreement on the dimensions and criteria used to judge the quality of conceptual models in educational technology. Therefore, the main goals of this article are to: (1) develop criteria to assess the quality and scope of conceptual models and (2) identify and compare exemplary models for technology integration in educational settings along with these quality criteria. The resulting five criteria from this investigation provide the means to effectively evaluate the quality and scope of conceptual models focused on technology integration while providing additional insight into applying these models in research and practice.


2009 ◽  
Vol 20 (10) ◽  
pp. 1521-1529 ◽  
Author(s):  
YAN-LONG LI ◽  
JUN MA ◽  
YAN-JUN LIU ◽  
LI-PING ZHANG ◽  
JUN-YAN SU

The order parameters and synchronization are numerically investigated in the time delay small-world connected FitzHugh–Nagumo excitable systems. The simulations show that the order parameter continuously decreases with increasing D, the quality of the synchronization worsens for large noise intensity. As the coupling intensity goes up, the quality of the synchronization worsens also, and find that the larger rewiring probability becomes, the larger-order parameter. At the same time, the order parameter goes up, the time delay declines. We obtained the complete phase diagram for a wide range of values of noise intensity D and control parameter g.


Sign in / Sign up

Export Citation Format

Share Document