Search results for " table"

DSMAV: An improved solution for multi-attribute search based on load capacities

2016

DHT (Distributed Hash Table) such as CHORD or PARTRY facilitates information searching in scalable systems. Two popular DHT-based approaches for range or multi-attribute search are to rely on attribute-value tree and a combination of attributes and values. However, tradeoff between a load balancing mechanism and query efficiency is a challenging task for such information searching systems. In this paper, we propose improved algorithms for a system called DSMAV in which information resources are distributed fairly among nodes and found based on multi-attribute queries in a small number of hop counts. Our system creates identifiers from resource names, each of which is a combination of attrib…

Magnetization states in ultrathin films with laterally modulated anisotropies

1998

Abstract Micromagnetic theory has been applied to a model system for ultrathin films with laterally modulated anisotropies, consisting of a periodic array of stripes with alternating uniaxial anisotropies. Despite of the discontinuous change of anisotropy, the magnetization direction only changes on a lateral scale given by the exchange length. If the width of one of the two alternating stripes is reduced below a critical value, the magnetization will switch into a uniform state. The variation of the critical width with period, anisotropy constants, exchange constant, and film thickness has been determined using an analytic approach. Non-uniform magnetization states and the magnetization re…

2019

Abstract This article contains intensity and aversiveness ratings of electrical stimuli and data on electrodermal activity (skin conductance level and skin conductance response) during an implicit conditioning procedure. Further, answers from a questionnaire on contingency awareness are provided. The experiment consisted of three phases. In the acquisition, two types of visual stimuli (CS+ and CS-) were coupled to weakly and moderately painful electrical stimuli presented to the participants’ (N = 48) dominant hand. In the test phase, after both CS+ and CS- only the weakly painful electrical stimuli were presented. In the contingency test phase, no more electrical stimuli were presented and…

Some determinants of the migration of professional manpower.

1975

Abstract Determinants of migration of professional manpower are investigated using data from a 1970 survey of immigrants to the United States. From a respondent’s stated “intent to stay” in the United States and five other characteristics a six-dimensional contingency table is formed. We find a well-fitting log-linear model for this table. Thus, we establish the importance of selected determinants of migration and present a table of predicted rates of intent to stay in the United States

An Overview of Collapsibility

2004

Collapsing over variables is a necessary procedure in much empirical research. Consequences are yet not always properly evaluated. In this paper, different definitions of collapsibility (simple, strict, strong, etc.) and corresponding necessary and sufficient conditions are reviewed and evaluated. We point out the relevance and limitations of the main contributions within a unifying interpretative framework. We deem such work to be useful since the debate on the topic has often developed in terms that are neither focused nor clear.

Automatic regrouping of strata in the goodness-of-fit chi-square test

2019

Pearson’s chi-square test is widely employed in social and health sciences to analyze categorical data and contingency tables. For the test to be valid, the sample size must be large enough to provide a minimum number of expected elements per category. This paper develops functions for regrouping strata automatically no matter where they are located, thus enabling the goodness-of-fit test to be performed within an iterative procedure. The functions are written in Excel VBA (Visual Basic for Applications) and in Mathematica. The usefulness and performance of these functions is illustrated by means of a simulation study and the application to different datasets. Finally, the iterative use of …

Finding condensed descriptions for multi-dimensional data.

1976

Abstract We describe two programs that may be used to find condensed descriptions for data available in a contingency table or in a covariance matrix in the case that these data follow a multinomial or a multivariate normal distribution, respectively. The programs perform a stepwise model search among multiplicative models by computing appropriate likelihood-ratio test statistics.

III: „Relatives Risiko” und „NNT” - anschauliche Maße für binäre Daten

2002

Description of categorial data can often be based on contingency tables. However, percentages appearing in such tables must be meaningful: For most applications, it may be useful to employ factors of causal influence as the row entry variable and relate percentages to sub-groups defined by these row entries ("row percentages"). The comparison of success frequencies (i. e. binary information on "therapy success yes/no") may be based on two therapies, respective success frequencies and their ratio, the relative risk. In addition the success frequencies' difference, the absolute (or excess) risk, can be transformed into the "number needed to treat" (NNT). Many international journals demand thi…

Collapsibility and Collapsing Multidimensional Contingency Tables—Perspectives and Implications

2000

Collapsing multidimensional contingency tables is a necessary procedure in all kinds of research. Since collapsibility is subject to severe conditions, collapsing is often not admissible without incurring severe interpretative errors. After having discussed the main contributions to the statistical specification of the concept, we shall point out the logical conditions for collapsing multidimensional contingency tables.

Utility of the Mantel-Haenszel Procedure for Detecting Differential Item Functioning in Small Samples

2004

Sample-size restrictions limit the contingency table approaches based on asymptotic distributions, such as the Mantel-Haenszel (MH) procedure, for detecting differential item functioning (DIF) in many practical applications. Within this framework, the present study investigated the power and Type I error performance of empirical and inferential criteria for DIF detection in small samples. Sample sizes (50/50, 100/50, 200/50, and 100/100 for the reference and focal groups, respectively), ability distributions (equal and unequal), and amount of DIF (moderate and high) were manipulated. The results show the advantages of employing theMHchi-square statistic using high levels of significance (•…