Bootstrap selection of ridge regularization parameter: a comparative study via a simulation study

Author(s):  
M. Revan Özkale ◽  
Hüsniye Altuner
2021 ◽  
Author(s):  
Mohammed Gamal ◽  
Ibrahim A. Naguib ◽  
Dibya Sundar Panda ◽  
Fatma F. Abdallah

The competencies of four greenness assessment tools were tested. AGREE is the best greenness tool while NEMI is the poorest one. AGREE, GAPI, and ESA are reliable greenness tools.


2015 ◽  
Vol 16 (1) ◽  
pp. 50-70 ◽  
Author(s):  
Jakob Cakarnis ◽  
Steve Peter D'Alessandro

Purpose – This paper investigates the determinants of credit card use and misuse by student and young professionals. Critical to the research is the impact of materialism and knowledge on selection of the appropriate credit card. Design/methodology/approach – This study uses survey research and partial least squares to investigate credit card behaviors of students versus young professionals. Findings – In a comparative study of young professionals and students, it was found that consumer knowledge, as expected, leads to better consumer selection of credit cards. Materialism was also found to increase the motivation for more optimal consumer outcomes. For more experienced consumers, such as young professionals, it was found that despite them being more knowledgeable, they were more likely to select a credit card based on impulse. Originality/value – This paper examines how materialism may in fact encourage some consumers to make better decisions because they are more motivated to develop better knowledge. It also shows how better credit card selection may inhibit impulse purchasing.


2012 ◽  
Vol 8 (2) ◽  
pp. 228-240 ◽  
Author(s):  
David Hunter ◽  
Hao Yu ◽  
Michael S. Pukish, III ◽  
Janusz Kolbusz ◽  
Bogdan M. Wilamowski

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mar Rodríguez-Girondo ◽  
Niels van den Berg ◽  
Michel H. Hof ◽  
Marian Beekman ◽  
Eline Slagboom

Abstract Background Although human longevity tends to cluster within families, genetic studies on longevity have had limited success in identifying longevity loci. One of the main causes of this limited success is the selection of participants. Studies generally include sporadically long-lived individuals, i.e. individuals with the longevity phenotype but without a genetic predisposition for longevity. The inclusion of these individuals causes phenotype heterogeneity which results in power reduction and bias. A way to avoid sporadically long-lived individuals and reduce sample heterogeneity is to include family history of longevity as selection criterion using a longevity family score. A main challenge when developing family scores are the large differences in family size, because of real differences in sibship sizes or because of missing data. Methods We discussed the statistical properties of two existing longevity family scores: the Family Longevity Selection Score (FLoSS) and the Longevity Relatives Count (LRC) score and we evaluated their performance dealing with differential family size. We proposed a new longevity family score, the mLRC score, an extension of the LRC based on random effects modeling, which is robust for family size and missing values. The performance of the new mLRC as selection tool was evaluated in an intensive simulation study and illustrated in a large real dataset, the Historical Sample of the Netherlands (HSN). Results Empirical scores such as the FLOSS and LRC cannot properly deal with differential family size and missing data. Our simulation study showed that mLRC is not affected by family size and provides more accurate selections of long-lived families. The analysis of 1105 sibships of the Historical Sample of the Netherlands showed that the selection of long-lived individuals based on the mLRC score predicts excess survival in the validation set better than the selection based on the LRC score . Conclusions Model-based score systems such as the mLRC score help to reduce heterogeneity in the selection of long-lived families. The power of future studies into the genetics of longevity can likely be improved and their bias reduced, by selecting long-lived cases using the mLRC.


2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Lisa Parola

This essay derives from the primary need to make order between direct and indirect sources available for the reconstruction of the history of video art in Italy in the seventies. In fact, during the researches for the Ph.D. thesis it became clear that in most cases it is difficult to define, in terms of facts, which of the different historiographies should be taken into consideration to deepen the study of video art in Italy. Beyond legitimate differences of perspectives and methods, historiographical narratives all share similar issues and narrative structure. The first intention of the essay is, therefore, to compare the different historiographic narratives on Italian video art of the seventies, verifying their genealogy, the sources used and the accuracy of the narrated facts. For the selection of the corpus, it was decided to analyze in particular monographic volumes dealing with the history of the origins of video art in Italy. The aim was, in fact, to get a wide range of types of "narrations", as in the case of contemporary art and architecture magazines, which are examined in the second part of the essay. After the selection, for an analytical and comparative study of the various historiography, the essay focuses only on the Terza Biennale Internazionale della Giovane Pittura. Gennaio ’70. Comportamenti, oggetti e mediazioni (Third International Biennial of Young Painting. January '70. Behaviors, Objects and Mediations, 1970, Bologna), the exhibition which - after Lucio Fontana's pioneering experiments - is said to be the first sign of the arrival of videotape in Italy (called at the time videorecording), curated by Renato Barilli, Tommaso Trini, Andrea Emiliani and Maurizio Calvesi. The narration given so far of this exhibition appeared more mythological than historical and could be compared structurally to that of the many numerous beginnings that historiographyies on international video art identify as ‘first’ and ‘generative’. In the first part of the essay the 'facts' related to Gennaio ’70, as narrated by historiography on video art, are compared. In the second part the survey is carried out through some of the direct sources identified during the research, with the aim of answering to questions raised by the comparison between historiographies. Concluding, it is important to underline that the tapes containing the videos transmitted have not been found and seem to have disappeared since the ending of the exhibition. Nevertheless, the deepening of the works and documentation transmitted during the exhibition is possible thanks to other types of sources which give us many valuable information regarding video techniques and practices at the beginning of 1970 in Italy.


2021 ◽  
Vol 1 (3) ◽  
pp. 9-36
Author(s):  
Luís Valadares Tavares ◽  
Pedro Arruda

Public procurement is a main issue in the frontline of Governments fighting COVID 19 pandemic as the need for additional and urgent acquisitions as well as the need to consolidate the supply chains and to promote sustainable and innovative procurement have been a source of deep changes and main challenges disturbing public markets and invalidating several assumptions of the traditional public contracting. In this paper, the development of appropriate public policies to cope with these challenges is studied following the approach suggested by several authors and including four stages: a Stage on Facts and Issues where the main challenges and conditions are studied, the Options Stage to describe which polices and procedures can be adopted, a Values Stage stating the main values to be pursued and, finally, a Policies Stage including the selection of the recommended policies. The analysis of the challenges and facts includes the study of a taxonomy of short and longer term needs and the available options are based on the comparative study of procedures ruled by the European Directives on Public Procurement approved on 2014. The major values to be respected include the principle of competition which is a major institutional principle of the European Treaty and of the Directives as well as the goal of promoting sustainable and innovative public procurement. Several indicators are suggested to describe the application of the public procurement policies adopted across EU and their comparative analysis is presented using the TED data for contracts concerning COVID 19. The case of Portugal is discussed and final remarks about the recommended public policies are also included herein.


2017 ◽  
Vol 40 (2) ◽  
pp. 205-221 ◽  
Author(s):  
Shahryar Mirzaei ◽  
Gholam Reza Mohtashami Borzadaran ◽  
Mohammad Amini

In this paper, we consider two well-known methods for analysis of the Gini index, which are U-statistics and linearization for some incomedistributions. In addition, we evaluate two different methods for some properties of their proposed estimators. Also, we compare two methods with resampling techniques in approximating some properties of the Gini index. A simulation study shows that the linearization method performs 'well' compared to the Gini estimator based on U-statistics. A brief study on real data supports our findings.


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