Tetrad

Observing the world and finding trends and relations among the variables of interest is an important and common learning activity. In this paper we apply TETRAD, a program that uses Bayesian networks to discover causal rules, and C4.5, which creates decision trees, to the problem of discovering relations among a set of variables in the controlled environment of an Artificial Life simulator. All data in this environment are generated by a single entity over time. The rules in the domain are known, so we are able to assess the effectiveness of each method. The agent’s sensings of its environment and its own actions are saved in data records over time. We first compare TETRAD and C4.5 in discovering the relations between variables in a single record. We next attempt to find temporal relations among the variables of consecutive records. Since both these programs disregard the passage of time among the records, we introduce the flattening operation as a way to span time and bring the variables of interest together in a new single record. We observe that flattening allows C4.5 to discover relations among variables over time, while it does not improve TETRAD’s output.

The purpose is to study systems of interacting particles, in the General Relativity context, by the principle of least action, using purely classical concepts. The particles are described by a state tensor, accounting for the kinematic part (rotation) using a Clifford algebra, and the interaction part (charges). The force fields, including gravitation and other forces, are described by connections on principal bundles. A solution has been found to account in the lagrangian for individual, pointlike, particles. The constraints induced by the equivariance (gauge) and covariance are reviewed. Modified Lagrange equations are written for general lagrangians. A model, based on scalarproducts, Diracoperatorandchirality isstudiedinmoredetails. Problems related to symmetries, including the Higgs mechanism, are introduced. With a comprehensive coverage of topics, and the purpose of finding

This paper reports the results of research investigating the determinants of the propensity to switch wireless service providers. A model generated from the data rather than from a priori theory is presented, and it is found to uphold the strong relationship between customer satisfaction ...

This paper reports the results of research investigating the determinants of the propensity to switch wireless service providers. A model generated from the data rather than from a priori theory is presented, and it is found to uphold the strong relationship between customer satisfaction and customer loyalty exhibited in prior studies. In sharp contrast to the prevailing industry practice of ‘locking in’ customers by means of restrictive contracts, this research suggests that wireless service providers are better off improving customer satisfaction in order to minimize customer defection. This would imply shifting scarce resources to customer retention through improved service, saving costs of expensive customer acquisition campaigns. The paper also proposes two methodological innovations. First, the research employs the ‘Tetrad methodology’ as an exploratory technique prior to building a Structural Equation Model (SEM) making it possible to identify drivers of loyalty—direct or ind...

In this paper I make connections between McLuhan’s “general media theory” (his historical-analogical-perceptual model of communication running throughout his media writings) and a few key areas in existential and hermeneutic phenomenology such as the intentionality of human experience, Being-in-the-world, meaning and worldly encounter, Verstehen, and, via the work of Don Ihde, technologically-mediated existence. First, I sketch out a few key comparisons between McLuhan’s ontology (his “general media theory”) and Heideggerian-inspired philosophies of experience and interpretation. Second, I link McLuhan’s epistemology (his tetradic “laws of media”) to Ihde’s “phenomenology of media,” showing how the phenomenological McLuhan is most evident in his proposal for the tetrad by exploring the strong complementarities between McLuhan’s “method” and Ihde’s four-part model of “human-technology relations.” Third, I attempt to provide context and a corrective to some of McLuhan’s problematic critiques of phenomenology and make the claim that McLuhan would have found much common ground and intellectual fodder for his media theories in the works of Heidegger, Merleau-Ponty, Gadamer, and Ricoeur. Ultimately, in the process of gradually unravelling an existentially phenomenological McLuhan, I make the claim that there is a latent but palpable communicational intentionality at the heart of McLuhan’s communication theory: For McLuhan, in our increasingly complex and technologically-mediated encounters with others and the greater world, the medium of communication (as the message) interplays with and influences, in varying degrees, how the world is encountered, projected onto, and reflected upon, simultaneously shaping our world as technology is in turn shaped by it. Finally, I conclude the paper with a speculative question: What if McLuhan had looked at phenomenology and Heideggerian-inspired philosophies of technology and human experience more closely? I believe it is fruitful to attempt to answer this question. The search for its answer, I claim, holds much promise for communication theory, technology assessment, and philosophy of technology research. With more explicitly phenomenological McLuhan, perhaps the “medium is the message” could have transformed into “Being-in-the-technologically-mediated-world is the message.”

The purpose is to study systems of interacting particles, in the General Relativity context, by the principle of least action, using purely classical concepts. The particles are described by a state tensor, accounting for the kinematic part (rotation) using a Clifford algebra, and the interaction part (charges). The force fields, including gravitation and other forces, are described by connections on principal bundles. A solution has been found to account in the lagrangian for individual, pointlike, particles. The constraints induced by the equivariance (gauge) and covariance are reviewed. Modified Lagrange equations are written for general lagrangians. A model, based on scalar products, Dirac operator and chirality is studied in more details. Problems related to symmetries, including the Higgs mechanism, are introduced. With a comprehensive coverage of topics, and the purpose of finding a physical meaning to the mathematical tools used, it can be a useful pedagogical study. But it ...

The purpose is to study systems of interacting particles in the Generl Relativity context, by the principle of least action using purely classical concepts. The particles are described by a state tensor using a Clifford algebra for the kinematic part. The force fields, including gravitation, are described by connections on principle bundles. A solution has been found to account for individual particles. A more specific model based on scalar products, Dirac operator and chirality is studied in more details. Problems related to symmetries, including the Higgs mechanism, are intoduced. With a comprehensive coverage of topics it can be a useful pedagogical study.