376,200 research outputs found

    Frequency Effects on Predictability of Stock Returns

    Full text link
    We propose that predictability is a prerequisite for profitability on financial markets. We look at ways to measure predictability of price changes using information theoretic approach and employ them on all historical data available for NYSE 100 stocks. This allows us to determine whether frequency of sampling price changes affects the predictability of those. We also relations between price changes predictability and the deviation of the price formation processes from iid as well as the stock's sector. We also briefly comment on the complicated relationship between predictability of price changes and the profitability of algorithmic trading.Comment: 8 pages, 16 figures, submitted for possible publication to Computational Intelligence for Financial Engineering and Economics 2014 conferenc

    Self-directedness, integration and higher cognition

    Get PDF
    In this paper I discuss connections between self-directedness, integration and higher cognition. I present a model of self-directedness as a basis for approaching higher cognition from a situated cognition perspective. According to this model increases in sensorimotor complexity create pressure for integrative higher order control and learning processes for acquiring information about the context in which action occurs. This generates complex articulated abstractive information processing, which forms the major basis for higher cognition. I present evidence that indicates that the same integrative characteristics found in lower cognitive process such as motor adaptation are present in a range of higher cognitive process, including conceptual learning. This account helps explain situated cognition phenomena in humans because the integrative processes by which the brain adapts to control interaction are relatively agnostic concerning the source of the structure participating in the process. Thus, from the perspective of the motor control system using a tool is not fundamentally different to simply controlling an arm

    Economic integration and export complexity: the case of Slovakia

    Get PDF
    The goal of the article is to evaluate the impact of the European Union (EU) accession on the complexity of goods in Slovak exports. The traditional theories or trade (Ricardian and Heckscher-Ohlin models) show that such an engagement in economic integration may lead to specialization in the production of either more or less sophisticated goods, depending on the country’s technological advancement and factor endowment. At the same time, increased FDI flows may stimulate the engagement of a country in international production chains with ambiguous effects on export complexity. Because it is impossible to a priori predict the effect economic integration may have on the complexity, it is reasonable to verify it empirically. The authors used the Synthetic Control Method (SCM) to compare the observed post-accession levels of exports complexity in Slovakia with the counterfactual values of that country remaining outside of the EU. The obtained results show that the accession led to an increase in complexity of exported goods

    Space exploration: The interstellar goal and Titan demonstration

    Get PDF
    Automated interstellar space exploration is reviewed. The Titan demonstration mission is discussed. Remote sensing and automated modeling are considered. Nuclear electric propulsion, main orbiting spacecraft, lander/rover, subsatellites, atmospheric probes, powered air vehicles, and a surface science network comprise mission component concepts. Machine, intelligence in space exploration is discussed

    The Alanine World Model for the Development of the Amino Acid Repertoire in Protein Biosynthesis

    Get PDF
    A central question in the evolution of the modern translation machinery is the origin and chemical ethology of the amino acids prescribed by the genetic code. The RNA World hypothesis postulates that templated protein synthesis has emerged in the transition from RNA to the Protein World. The sequence of these events and principles behind the acquisition of amino acids to this process remain elusive. Here we describe a model for this process by following the scheme previously proposed by Hartman and Smith, which suggests gradual expansion of the coding space as GC–GCA–GCAU genetic code. We point out a correlation of this scheme with the hierarchy of the protein folding. The model follows the sequence of steps in the process of the amino acid recruitment and fits well with the co-evolution and coenzyme handle theories. While the starting set (GC-phase) was responsible for the nucleotide biosynthesis processes, in the second phase alanine-based amino acids (GCA-phase) were recruited from the core metabolism, thereby providing a standard secondary structure, the α-helix. In the final phase (GCAU-phase), the amino acids were appended to the already existing architecture, enabling tertiary fold and membrane interactions. The whole scheme indicates strongly that the choice for the alanine core was done at the GCA-phase, while glycine and proline remained rudiments from the GC-phase. We suggest that the Protein World should rather be considered the Alanine World, as it predominantly relies on the alanine as the core chemical scaffold.TU Berlin, Open-Access-Mittel - 201

    Self-assembly mechanism of pH-responsive glycolipids : micelles, fibers, vesicles, and bilayers

    Get PDF
    A set of four structurally related glycolipids are described: two of them have one glucose unit connected to either stearic or oleic acid, and two other ones have a diglucose headgroup (sophorose) similarly connected to either stearic or oleic acid. The self-assembly properties of these compounds, poorly known, are important to know due to their use in various fields of application from cleaning to cosmetics to medical. At basic pH, they all form mainly small micellar aggregates. At acidic pH, the oleic and stearic derivatives of the monoglucose form, respectively, vesicles and bilayer, while the same derivatives of the sophorose headgroup form micelles and twisted ribbons. We use pH-resolved in situ small angle X-ray scattering (SAXS) under synchrotron radiation to characterize the pH-dependent mechanism of evolution from micelles to the more complex aggregates at acidic pH. By pointing out the importance of the COO-/COOH ratio, the melting temperature, T-m, of the lipid moieties, hydration of the glycosidic headgroup, the packing parameter, membrane rigidity, and edge stabilization, we are now able to draw a precise picture of the full self-assembly mechanism. This work is a didactical illustration of the complexity of the self-assembly process of a stimuli-responsive amphiphile during which many concomitant parameters play a key role at different stages of the process

    Maximum Entropy Production Principle for Stock Returns

    Full text link
    In our previous studies we have investigated the structural complexity of time series describing stock returns on New York's and Warsaw's stock exchanges, by employing two estimators of Shannon's entropy rate based on Lempel-Ziv and Context Tree Weighting algorithms, which were originally used for data compression. Such structural complexity of the time series describing logarithmic stock returns can be used as a measure of the inherent (model-free) predictability of the underlying price formation processes, testing the Efficient-Market Hypothesis in practice. We have also correlated the estimated predictability with the profitability of standard trading algorithms, and found that these do not use the structure inherent in the stock returns to any significant degree. To find a way to use the structural complexity of the stock returns for the purpose of predictions we propose the Maximum Entropy Production Principle as applied to stock returns, and test it on the two mentioned markets, inquiring into whether it is possible to enhance prediction of stock returns based on the structural complexity of these and the mentioned principle.Comment: 14 pages, 5 figure

    What Are the Useful Past Inter-Organizational Relationships (IORs) for Forming Complex IORs?

    Get PDF
    Purpose: The purpose is to explore the relationship between prior and later inter-organizational relationships (IORs) by studying whether past experience can be leveraged on when forming new, more complex, IORs. Methodology: Participation in prior IORs is characterized in terms of both resource- transferring and resource-pooling IORs in home-country networks, while complex IORs are considered those with foreign partners. An empirical test on 366 Italian firms is performed using OLS with robust standard errors. Findings: Both resource-transferring and resource-pooling IORs have non-convergent effects. The former has controversial effects on the base of the position a firm occupies, that in turn affects the structure of interests between the partners. The latter has different effects in line with the information complexity of the objective of the relationship. Research Implications: Results provide support to the idea that structure of interests and information complexity represent \u201cdiscriminating characteristics\u201d that identify salient structural alternatives in the analysis of inter-firm organization. Practical Implications: The paper advances that firms can partially leverage on the exploitation of prior experience in settings that are explorative in nature, by carefully selecting within past experiences. Originality: A distinction between coordination \u201cgiving\u201d and coordination \u201ctaking\u201d IORs is proposed to discern among different types of inter-firm coordination forms

    Astrobiological Complexity with Probabilistic Cellular Automata

    Full text link
    Search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous input parameters' space. We perform a simple clustering analysis of typical astrobiological histories and discuss the relevant boundary conditions of practical importance for planning and guiding actual empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.Comment: 37 pages, 11 figures, 2 tables; added journal reference belo

    Metastability, Criticality and Phase Transitions in brain and its Models

    Get PDF
    This essay extends the previously deposited paper "Oscillations, Metastability and Phase Transitions" to incorporate the theory of Self-organizing Criticality. The twin concepts of Scaling and Universality of the theory of nonequilibrium phase transitions is applied to the role of reentrant activity in neural circuits of cerebral cortex and subcortical neural structures
    corecore