A valid theory on probabilistic causation

In this paper several definitions of probabilistic causation are considered, and their main drawbacks discussed. Current notions of probabilistic causality have symmetry limitations (e.g. correlation and statistical dependence are symmetric notions). To avoid the symmetry problem, non-reciprocal causality is often defined in terms of dynamic asymmetry. But these notions are likely to consider spurious regularities. In this paper we present a definition of causality that does non have symmetry inconsistences. It is a natural extension of propositional causality in formal logics, and it can be easily analyzed with statistical inference. The modeling problems are also discussed using empirical processes.Causality, Empirical Processes and Classification Theory, 62M30, 62M15, 62G20

The Effectiveness of <i>t</i>-Way Test Data Generation

Modern society is increasingly dependent on the correct functioning of software and increasingly so in areas that are considered safety related or safety critical. Therefore, there is an increasing need to be able to verify and validate that the software is in fact correct and will perform its intended function. Many approaches to this problem have been proposed; however, none seems likely to supplant the role of testing in the near future. If we accept that there is, and will be, a continuing need to be able to test software then the question becomes one of how can this be done effectively, both in terms of ability to detect errors and in terms of cost. One avenue of research that offers prospects of improving both of these aspects is the automatic generation of test data. There has recently been a large amount of work conducted in this area. One particularly promising direction has been the application of ideas from the field of experimental design and in particular, the field of t-way adequate factorial designs. The area however, is not without issues; there is evidence that the technique is capable of detecting errors but that evidence is not unequivocal. Moreover, as with almost all work in the area of automatic test generation, there has been very little comparative work comparing the technique with other test data generation techniques. Worse, there has been effectively no work done that compares any automatic test data generation technique with the effectiveness of tests generated by humans. Another major issue with the technique is the number of tests that applying the technique can result in. This implies that there is a need for an automated oracle if the technique is to be successfully applied. The flaw with this is of course that in most situations the oracle is the human that is conducting the tests, a point often ignored in testing research. The work presented here addresses both of these points. To do this I have used a code base taken from an industrial engine control system that has an existing set of high quality unit tests developed by hand. To complement this, several other techniques for automatically generating test data have been applied, namely random testing, random experimental designs and a technique for generating single factor experiments. To address the issue of being able to compare the error detection ability of all of the sets of test vectors, rather than the usual effectiveness surrogates of code coverage I have used mutation analysis on the code base to directly measure the ability of each set of test vectors to discover common coding errors. The results presented here show that test data generation techniques based on t-way factorial designs are at least as effective as handgenerated tests and superior to random testing and the factor experimental technique. The oracle problem associated with the factorial design techniques was addressed using a test set minimisation approach. The mutation tool monitored which vectors could “kill” which code mutants. After a subset of the test vectors had been run, the most effective vectors were retained and the rest discarded. Likewise, mutants that were killed were removed from further consideration and the process repeated. Experimental results show that this minimisation procedure is effective at reducing computational overhead and is capable of producing final sets of test vectors that are comparable in size with the sets of hand-generated tests and so amenable to final hand checking

Dagstuhl News January - December 2002

"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic

Precise Regulation of Gene Expression Dynamics Favors Complex Promoter Architectures

Promoters process signals through recruitment of transcription factors and RNA polymerase, and dynamic changes in promoter activity constitute a major noise source in gene expression. However, it is barely understood how complex promoter architectures determine key features of promoter dynamics. Here, we employ prototypical promoters of yeast ribosomal protein genes as well as simplified versions thereof to analyze the relations among promoter design, complexity, and function. These promoters combine the action of a general regulatory factor with that of specific transcription factors, a common motif of many eukaryotic promoters. By comprehensively analyzing stationary and dynamic promoter properties, this model-based approach enables us to pinpoint the structural characteristics underlying the observed behavior. Functional tradeoffs impose constraints on the promoter architecture of ribosomal protein genes. We find that a stable scaffold in the natural design results in low transcriptional noise and strong co-regulation of target genes in the presence of gene silencing. This configuration also exhibits superior shut-off properties, and it can serve as a tunable switch in living cells. Model validation with independent experimental data suggests that the models are sufficiently realistic. When combined, our results offer a mechanistic explanation for why specific factors are associated with low protein noise in vivo. Many of these findings hold for a broad range of model parameters and likely apply to other eukaryotic promoters of similar structure

Derived Relational Responding, Transformation of Psychological Stimulus Functions, and Avoidance in Mothers of Clinically Referred Children for Anxiety and Related Disorders

Accommodation is a parenting behavior that is highly prevalent, has a strong association with child anxiety, and that persists despite its deleterious effects (e.g., Benito et al., 2015; Lebowitz et al., 2013; Thompson-Hollands, Kerns, Pincus, & Comer, 2014). While little is known about the psychological processes that motivate parents to engage in accommodating behaviors, conceptual models suggest that parental behavior may be influenced by avoidance of parental distress and cognitions around child anxiety (e.g., Feinberg, Kerns, Pincus, & Comer, 2018; Jones, Lebowitz, Marin, & Stark, 2015). However, most of the research in this domain is correlational, precluding knowledge regarding the possible influence or function that parents’ perceptions of their children’s anxiety may have on their parenting behavior. Relational frame theory (RFT; Hayes, Barnes-Holmes, & Roche, 2001), a behavioral-analytic account of human language and cognition, allows for the experimental research of cognitive processes, as it conceptualizes cognitions as verbal behavior. The purpose of the present study was to explore derived relational responding in parents of anxious children and its potential role in avoidance based parenting behavior. Specifically, five parents of anxious children provided words describing their children’s anxiety (aversive stimuli), sources of joy (appetitive stimuli), descriptions of neutral objects (neutral stimuli) and positive parenting values (appetitive stimuli for a second experiment). This study used an alternating treatments single case experimental design across participants to explore latency and errors in derived relations across the three stimulus classes. I expected that mothers would: Hypothesis One: Form equivalence classes faster and with fewer errors between aversive child anxiety and novel stimuli relative to neutral novel or appetitive-novel stimuli, Hypothesis Two: take more time and make more errors in forming classes with aversive child anxiety stimuli and parenting values stimuli, compared to neutral-parenting values and appetitive-parenting values stimuli, Hypothesis Three: avoid visual stimuli previously associated with child anxiety stimuli, and Hypothesis Four: self-report elevated perception of child anxiety, parental avoidance, autonomy granting behavior and Hypothesis Five: self-report elevated cognitive fusion, experiential avoidance, and trait anxiety. Hypotheses were partially supported. Most mothers formed functional equivalence classes among novel symbols and aversive child anxiety words faster and with less errors than when forming relations between novel symbols and either neutral or appetitive words. Mothers did not show a systematic tendency to form equivalence classes with stimuli of incongruent psychological functions more slowly or with more errors than when forming classes between other stimuli. While participants 1 through 4 selected symbols systematically, only 1 and 3 avoided the symbols that had acquired aversive psychological functions on all trials. Results support the possibility that parents of anxious children may be less sensitive to other stimuli when stimuli about their children’s anxiety is present. Limitations of this study include not having a participant whose child did not struggle with anxiety, as well as some novel stimuli having psychological properties prior to the experimental tasks. Other implications are discussed