RRS + LS-SVM: a new strategy for “a priori” sample selection

2007 ◽  
Vol 16 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Bernardo Penna Resende de Carvalho ◽  
Wilian Soares Lacerda ◽  
Antônio de Pádua Braga
Keyword(s):  
A Priori ◽  
Sample Selection ◽  
New Strategy

Assessing endogeneity issues in international marketing research

2016 ◽  
Vol 33 (3) ◽  
pp. 483-512 ◽  
Author(s):  
Ruey-Jer "Bryan" Jean ◽  
Ziliang Deng ◽  
Daekwan Kim ◽  
Xiaohui Yuan
Keyword(s):  
Structural Equation ◽  
A Priori ◽  
International Marketing ◽  
Sample Selection ◽  
Marketing Research ◽  
Equation Modeling ◽  
Potential Threat ◽  
Comprehensive Overview ◽  
Content Type ◽  
Main Independent Variable

Purpose – Endogeneity is a potential threat to the validity of international marketing (IM) research. The purpose of this paper is to draw the attention of IM researchers to issues of endogeneity, to provide a comprehensive overview of the sources of endogeneity, and to discuss the statistical solutions. Design/methodology/approach – The authors conduct the research in two steps. In the first step, the authors review the nature and sources of endogeneity specifically in IM research. In the second step, the authors review 60 IM papers on endogeneity published in the period 1995-2014 and assess the current practice of addressing endogeneity in the IM literature. Findings – Sample selection bias and simultaneity are prevalent sources of endogeneity in IM research. Internationalization-performance relationship and innovation-export nexus are the two most frequently adopted models subject to potential endogeneity. Simply lagging the main independent variable is statistically flawed in dealing with endogeneity despite its popularity in IM research. Research limitations/implications – First, a careful choice and application of methods are critical when addressing endogeneity. Second, the authors suggest the employment of multiple study methods to address endogeneity robustly. Third, to prevent or solve endogeneity in structural equation modeling, researchers may either collect data on independent and dependent variables from different respondents or employ a two-stage least squares approach. Finally, it is helpful to design dedicated models to prevent proactively potential endogeneity a priori. Originality/value – The contribution of this study is twofold. First, it is the first in the literature to discuss the endogeneity issue specifically in IM research. In particular, the study elaborates the origins and consequences of the three most frequently confronted types of endogeneity in IM research. Second, the authors assess the four major methods of addressing endogeneity in IM research with a systematic discussion of the literature from the last two decades. The authors offer suggestions on how to minimize endogeneity in model design and empirical implementation for future IM research.

scholarly journals A Priori Approach Of Real-Time Ridesharing Problem With Intermediate Meeting Locations

2014 ◽  
Vol 4 (4) ◽  
pp. 287-299 ◽  
Author(s):  
Kamel Aissat ◽  
Ammar Oulamara
Keyword(s):  
A Priori ◽  
Cost Savings ◽  
Travel Cost ◽  
Cost Rate ◽  
Common Path ◽  
The Core ◽  
New Strategy ◽  
Empirical Performance ◽  
The Common ◽  
Starting Location

Abstract Ridesharing is a mobility concept in which a trip is shared by a vehicle’s driver and one or more passengers called riders. Ridesharing is considered as a more environmentally friendly alternative to single driver commutes in pollution-creating vehicles on overcrowded streets. In this paper, we present the core of a new strategy of the ridesharing system, making it more flexible and competitive than the recurring system. More precisely, we allow the driver and the rider to meet each other at an intermediate starting location and to separate at another intermediate ending location not necessarily their origins and destinations, respectively. This allows to reduce both the driver’s detour and the total travel cost. The term “A priori approach” means that the driver sets the sharing cost rate on the common path with rider in advance. An exact and heuristic approaches to identify meeting locations, while minimizing the total travel cost of both driver and rider are proposed. Finally, we analyze their empirical performance on a set of real road networks consisting of up to 3,5 million nodes and 8,7 million edges. Our experimental results show that our heuristics provide efficient performances within short CPU times and improves the recurring ridesharing approach in terms of cost-savings.

scholarly journals Challenging the 'hidden' assumption in J. L. Schellenberg's hiddenness argument: an exploration into the nature of divine love

2021 ◽  
Author(s):  
Adam T. Blackburn
Keyword(s):  
A Priori ◽  
Divine Love ◽  
Probabilistic Support ◽  
God's Love ◽  
New Strategy ◽  
Perfect Being Theology

In recent years, J. L. Schellenberg has developed and defended a forceful argument for atheism. He argues that the existence of inculpable nonbelief, together with the (a priori) claim that this is not what we would expect if a perfectly loving God exists, provides probabilistic support for atheism. In response, most critics have focused on either denying the existence of inculpable nonbelief offering reasons why it is compatible with the existence of a perfectly loving God. I propose a new strategy for responding to Schellenberg's argument, however, which focuses on clarifying what perfect love entails. I claim that since Schellenberg employs perfect being theology in formulating his argument, he is thereby committed to the assumption that perfect love entails infinite love. I argue, however, that this assumption is unwarranted, and that if it can be shown that God's love is possibly not infinite, then Schellenberg's argument fails.

scholarly journals Challenging the 'hidden' assumption in J. L. Schellenberg's hiddenness argument: an exploration into the nature of divine love

2021 ◽  
Author(s):  
Adam T. Blackburn
Keyword(s):  
A Priori ◽  
Divine Love ◽  
Probabilistic Support ◽  
God's Love ◽  
New Strategy ◽  
Perfect Being Theology

In recent years, J. L. Schellenberg has developed and defended a forceful argument for atheism. He argues that the existence of inculpable nonbelief, together with the (a priori) claim that this is not what we would expect if a perfectly loving God exists, provides probabilistic support for atheism. In response, most critics have focused on either denying the existence of inculpable nonbelief offering reasons why it is compatible with the existence of a perfectly loving God. I propose a new strategy for responding to Schellenberg's argument, however, which focuses on clarifying what perfect love entails. I claim that since Schellenberg employs perfect being theology in formulating his argument, he is thereby committed to the assumption that perfect love entails infinite love. I argue, however, that this assumption is unwarranted, and that if it can be shown that God's love is possibly not infinite, then Schellenberg's argument fails.

scholarly journals Rotaxane CoII Complexes as Field-Induced Single-Ion Magnets

2021 ◽  
Author(s):  
Martina Cirulli ◽  
Enrico Salvadori ◽  
Zhi-Hui Zhang ◽  
Michael Dommett ◽  
Floriana Tuna ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Metal Ion ◽  
A Priori ◽  
Magnetic Behavior ◽  
Zero Field ◽  
Reliable Control ◽  
Chelating Ligands ◽  
Protein Cavity ◽  
New Strategy ◽  
Coordination Behavior

Mechanically chelating ligands have untapped potential for the engineering of metal ion properties by providing reliable control of the number, nature and geometry of donor atoms, akin to how a protein cavity controls the properties of bound metal ions. Here we demonstrate this principle in the context of Co<sup>II</sup>-based single-ion magnets. Using multi-frequency EPR, susceptibility and magnetization measurements we found that these complexes show some of the highest zero field splittings reported for five-coordinate Co<sup>II</sup> complexes to date. The predictable coordination behavior of the interlocked ligands allowed the magnetic properties of their Co<sup>II</sup> complexes to be evaluated computationally <i>a priori </i>and our combined experimental and theoretical approach enabled us to rationalize the observed trends. The predictable magnetic behavior of the rotaxane Co<sup>II</sup> complexes demonstrates that interlocked ligands offer a new strategy to design metal complexes with interesting functionality.

scholarly journals Rotaxane CoII Complexes as Field-Induced Single-Ion Magnets

2021 ◽  
Author(s):  
Martina Cirulli ◽  
Enrico Salvadori ◽  
Zhi-Hui Zhang ◽  
Michael Dommett ◽  
Floriana Tuna ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Metal Ion ◽  
A Priori ◽  
Magnetic Behavior ◽  
Zero Field ◽  
Reliable Control ◽  
Chelating Ligands ◽  
Protein Cavity ◽  
New Strategy ◽  
Coordination Behavior

Mechanically chelating ligands have untapped potential for the engineering of metal ion properties by providing reliable control of the number, nature and geometry of donor atoms, akin to how a protein cavity controls the properties of bound metal ions. Here we demonstrate this principle in the context of Co<sup>II</sup>-based single-ion magnets. Using multi-frequency EPR, susceptibility and magnetization measurements we found that these complexes show some of the highest zero field splittings reported for five-coordinate Co<sup>II</sup> complexes to date. The predictable coordination behavior of the interlocked ligands allowed the magnetic properties of their Co<sup>II</sup> complexes to be evaluated computationally <i>a priori </i>and our combined experimental and theoretical approach enabled us to rationalize the observed trends. The predictable magnetic behavior of the rotaxane Co<sup>II</sup> complexes demonstrates that interlocked ligands offer a new strategy to design metal complexes with interesting functionality.

The Role of Sampling in Strategic Management Research on Performance: A Two-Study Analysis

2002 ◽  
Vol 28 (3) ◽  
pp. 363-385 ◽  
Author(s):  
Jeremy C. Short ◽  
David J. Ketchen ◽  
Timothy B. Palmer
Keyword(s):  
Strategic Management ◽  
Organizational Performance ◽  
Random Sample ◽  
A Priori ◽  
Sample Selection ◽  
Negative Relationship ◽  
Chief Executive ◽  
Simple Random Sample ◽  
Management Journal ◽  
And Performance

Strategic management researchers often note the inability of many phenomena to consistently explain organizational performance. Using a two-study format, we examine the possibility that sampling practices may contribute to this inability. We chronicle sampling practices within 437 studies investigating the determinants of organizational performance published between 1980 and 1999 in the Academy of Management Journal, Administrative Science Quarterly, Journal of Management, Organization Science, and Strategic Management Journal. Our results reveal that fewer than one in five studies rely on a random sample and that researchers offer little a priori acknowledgement of sample limitations. Although the first study suggests that sampling issues have been problematic, it cannot offer direct evidence. Thus, in the second study, we examine the effect of sample selection on empirical results by testing one popular relationship from the strategy literature (chief executive officer duality and performance) using four different samples. Whereas a stratified random sample offers some evidence of a positive relationship, a purposive sample detects a negative relationship and an available sample and simple random sample detect no relationship. Taken together, the studies suggest that sampling practices must improve if strategic management is to approach its objective of explaining performance. Accordingly, several exemplar studies are described and recommendations are offered to guide future sampling practices.

scholarly journals Scanning Reduction Strategy in MEG/EEG Beamformer Source Imaging

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Jun Hee Hong ◽  
Sung Chan Jun
Keyword(s):  
A Priori ◽  
Computation Time ◽  
Correlated Sources ◽  
Source Imaging ◽  
Good Spatial Resolution ◽  
New Strategy ◽  
Localization Performance ◽  
Priori Information ◽  
Interesting Area ◽  
Robust To Noise

MEG/EEG beamformer source imaging is a promising approach which can easily address spatiotemporal multi-dipole problems without a priori information on the number of sources and is robust to noise. Despite such promise, beamformer generally has weakness which is degrading localization performance for correlated sources and is requiring of dense scanning for covering all possible interesting (entire) source areas. Wide source space scanning yields all interesting area images, and it results in lengthy computation time. Therefore, an efficient source space scanning strategy would be beneficial in achieving accelerated beamformer source imaging. We propose a new strategy in computing beamformer to reduce scanning points and still maintain effective accuracy (good spatial resolution). This new strategy uses the distribution of correlation values between measurements and lead-field vectors. Scanning source points are chosen yielding higher RMS correlations than the predetermined correlation thresholds. We discuss how correlation thresholds depend on SNR and verify the feasibility and efficacy of our proposed strategy to improve the beamformer through numerical and empirical experiments. Our proposed strategy could in time accelerate the conventional beamformer up to over 40% without sacrificing spatial accuracy.

Complete In-plane Elastic Characterisation under Tensile Tests of Angle-Ply Laminates Composed of Polymer-Matrix Layers

2002 ◽  
Vol 10 (7) ◽  
pp. 483-492
Author(s):  
E. Valot ◽  
P. Vannucci ◽  
G. Verchery
Keyword(s):  
Elastic Properties ◽  
Plate Theory ◽  
A Priori ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Simple Method ◽  
Elementary Layer ◽  
Specific Direction ◽  
New Strategy ◽  
Angle Ply Laminates

In this paper we present a new strategy to completely characterise the in-plane elastic properties of a large range of angle-ply laminates using only unidirectional tests. We consider laminates having the same number of identical plies in the α and – α directions. This new method uses some preceding results found by Verchery for orthotropic laminates, namely the conditions of existence of a specific direction ω, in which the shear-extension coupling is null. The characterisation of the laminate is then made using the results of three tensile tests: two in the orthotropy axes, and the third one in the ω direction, in order to have always a pure one-dimensional state of stress. We show that for the most common unidirectional fibre-reinforced materials, the angle ω is, in most cases, close to the α direction of the fibres. This result permits a complete experimental characterisation of the laminate, which then does not need any a priori knowledge of the elastic properties of the elementary layer. In addition, it provides a simple method to verify the predictions of the laminate behaviour obtained by the Classical Laminated Plate Theory (CLPT) when the elementary layer is completely known. The paper ends with numerical examples and with the results of some experimental tests.

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