An examination of the effect of six types of error perturbation on fifteen clustering algorithms

An evaluation of several clustering methods was conducted. Artificial clusters which exhibited the properties of internal cohesion and external isolation were constructed. The true cluster structure was subsequently hidden by six types of error-perturbation. The results indicated that the hierarchical methods were differentially sensitive to the type of error perturbation. In addition, generally poor recovery performance was obtained when random seed points were used to start theK-means algorithms. However, two alternative starting procedures for the nonhierarchical methods produced greatly enhanced cluster recovery and were found to be robust with respect to all of the types of error examined.     

Generating interior search directions for multiobjective linear programming

A new multiobjective linear programming (MOLP) algorithm is presented. The algorithm uses a variant of Karmarkar's interior-point algorithm known as the affine-scaling primal algorithm. Using this single-objective algorithm, interior search directions are generated and used to provide an approximation to the gradient of the (implicitly known) utility function. The approximation is guided by assessing locally relevant preference information for the various interior directions through interaction with a decision maker (DM). The resulting algorithm is an interactive approach that makes its progress towards the solution through the interior of the constraints polytope.     

Sometimes it does hurt to ask: The constructive role of articulating impressions

Decisions can sometimes have a constructive role, so that the act of, for example, choosing one option over another creates a preference for that option (e.g., , ,  and ). In this work we explore the constructive role of just articulating an impression, for a presented visual stimulus, as opposed to making a choice (specifically, the judgments we employ are affective evaluations). Using quantum probability theory, we outline a cognitive model formalizing such a constructive process. We predict a simple interaction, in relation to how a second image is evaluated, following the presentation of a first image, depending on whether there is a rating for the first image or not. The interaction predicted by the quantum model was confirmed across three experiments and a variety of control manipulations. The advantages of using quantum probability theory to model the present results, compared with existing models of sequence order effects in judgment (e.g., Hogarth & Einhorn, 1992) or other theories of constructive processes when a choice is made (e.g.,  and ) are discussed.     

From Copenhagen to the consulting room: Pauli and Jung in Copenhagen

In this paper the city of Copenhagen is used as a starting point to highlight some critical historical events, both concerning the exchange of ideas between the physicist Wolfgang Pauli and C.G. Jung and the history of psychotherapy in Scandinavia. Pauli's years in Copenhagen under the influence of Niels Bohr and his philosophy prepared him mentally to receiveC.G. Jung's ideas. The paper also recounts the one occasion that Jung was in Scandinavia, attending the 9th conference of the General Medical Society for Psychotherapy in Copenhagen, just before going to New York in 1937 to give his final seminars on Pauli's dreams. The reason for focusing on these particular events is that they also constitute part of the history of the reception of psychodynamic psychology in Sweden and Scandinavia.     

Neuroscience,quantum indeterminism and the Cartesian soul

Quantum indeterminism is frequently invoked as a solution to the problem of how a disembodied soul might interact with the brain (as Descartes proposed), and is sometimes invoked in theories of libertarian free will even when they do not involve dualistic assumptions. Taking as example the Eccles–Beck model of interaction between self (or soul) and brain at the level of synaptic exocytosis, I here evaluate the plausibility of these approaches. I conclude that Heisenbergian uncertainty is too small to affect synaptic function, and that amplification by chaos or by other means does not provide a solution to this problem. Furthermore, even if Heisenbergian effects did modify brain functioning, the changes would be swamped by those due to thermal noise. Cells and neural circuits have powerful noise-resistance mechanisms, that are adequate protection against thermal noise and must therefore be more than sufficient to buffer against Heisenbergian effects. Other forms of quantum indeterminism must be considered, because these can be much greater than Heisenbergian uncertainty, but these have not so far been shown to play a role in the brain.     

Natural language semantics in biproduct dagger categories

Biproduct dagger categories serve as models for natural language. In particular, the biproduct dagger category of finite dimensional vector spaces over the field of real numbers accommodates both the extensional models of predicate calculus and the intensional models of quantum logic. The morphisms representing the extensional meanings of a grammatical string are translated to morphisms representing the intensional meanings such that truth is preserved. Pregroup grammars serve as the tool that transforms a grammatical string into a morphism. The chosen linguistic examples concern negation, relative noun phrases, comprehension and quantifiers.     

Is the Brain a Quantum Computer?

We argue that computation via quantum mechanical processes is irrelevant to explaining how brains produce thought, contrary to the ongoing speculations of many theorists. First, quantum effects do not have the temporal properties required for neural information processing. Second, there are substantial physical obstacles to any organic instantiation of quantum computation. Third, there is no psychological evidence that such mental phenomena as consciousness and mathematical thinking require explanation via quantum theory. We conclude that understanding brain function is unlikely to require quantum computation or similar mechanisms.     

The structure of “communities” and communications in the new millennium

The three lineages of information,—the genetic, the cultural and artifactual—will increasingly merge their constituent information contents through advances in biotechnology and information technology. This will redefine what constitutes “social” and what constitutes “community.” A community's members communicate with their “significant others” and change their internal information states (and their internal and external behaviors). Under conditions of merging, information exchanges occur across all the three lineages. In this sense, the concept of significant other,—that is, a communicating entity—, is now spread from human communities to encompass also the biological and the artifactual. A seamless merging between the three realms now occurs affecting their respective internal information stores. The resulting image of interactions that now arises is of multiple oceans of communities, operating at different levels, the genetic, the cultural and the artifactual. There are exchanges across the different levels, up and down and sideways, as information is translated from one realm to the other. These dynamics result in changes in the evolutionary characteristics of each lineage and sub‐lineage, including the internal perceptions from within a lineage, namely in the language of evolutionary epistemology, its “meanings” and “hypotheses” on the world. A future sociology must necessarily take into account these factors and incorporate the dynamics of all three realms.     

Subjectivist – observing and objective – participant perspectives on the world: Kant,aquinas and quantum mechanics

Theological thinking is influenced by perspectives on the relation of scientific knowledge to reality. Two paradigms for understanding the nature of human knowledge are considered in relation to quantum mechanics: the subjective-observing perspective of Kant, and the objective-participant perspective of Thomas Aquinas. I discuss whether quantum mechanics necessarily implies a subject centered perspective on reality, and argue, with reference to d'Espagnat's notion of veiled reality, that quantum non-separability challenges this view. I then explore whether the objective-participant perspective of Thomas Aquinas provides a more fruitful context for understanding quantum mechanics. I discuss quantum measurement in terms of the transition from potentiality to actuality, and knowledge as the latent intelligibility of the world realized. However, the negative nature of our knowledge of quantum non-separability also challenges this perspective. Our theological thinking in response to quantum knowledge must therefore proceed tentatively, balancing a via positiva, with a via negativa.     

Bayesian Factor Analysis as a Variable-Selection Problem: Alternative Priors and Consequences

Factor analysis is a popular statistical technique for multivariate data analysis. Developments in the structural equation modeling framework have enabled the use of hybrid confirmatory/exploratory approaches in which factor-loading structures can be explored relatively flexibly within a confirmatory factor analysis (CFA) framework. Recently, Muthén & Asparouhov proposed a Bayesian structural equation modeling (BSEM) approach to explore the presence of cross loadings in CFA models. We show that the issue of determining factor-loading patterns may be formulated as a Bayesian variable selection problem in which Muthén and Asparouhov's approach can be regarded as a BSEM approach with ridge regression prior (BSEM-RP). We propose another Bayesian approach, denoted herein as the Bayesian structural equation modeling with spike-and-slab prior (BSEM-SSP), which serves as a one-stage alternative to the BSEM-RP. We review the theoretical advantages and disadvantages of both approaches and compare their empirical performance relative to two modification indices-based approaches and exploratory factor analysis with target rotation. A teacher stress scale data set is used to demonstrate our approach.