Homo Socionicus: a Case Study of Simulation Models of Norms

This paper describes a survey of normative agent-based social simulation models. These models are examined from the perspective of the foundations of social theory. Agent-based modelling contributes to the research program of methodological individualism. Norms are a central concept in the role theoretic concept of action in the tradition of Durkheim and Parsons. This paper investigates to what extend normative agent-based models are able to capture the role theoretic concept of norms. Three methodological core problems are identified: the question of norm transmission, normative transformation of agents and what kind of analysis the models contribute. It can be shown that initially the models appeared only to address some of these problems rather than all of them simultaneously. More recent developments, however, show progress in that direction. However, the degree of resolution of intra agent processes remains too low for a comprehensive understanding of normative behaviour regulation.Norms, Normative Agent-Based Social Simulation, Role Theory, Methodological Individualism

Establishing a Sustainable Development Goal for Oceans and Coasts to Face the Challenges of our Future Ocean

Oceans regulate our climate, provide us with natural resources such as food, materials, substances, and energy and are essential for international trade, recreational, and cultural activities. Free access to and availability of ocean resources and services, together with human development, have put strong pressures on marine ecosystems, ranging from overfishing and reckless resource extraction to various channels of careless pollution. International cooperation and negotiations are required to protect the marine environment and use marine resources in a way that the needs of future generations will be met. For that purpose, developing and agreeing on a Sustainable Development Goal (SDG) Oceans and Coasts could be an essential element for sustainable ocean management. The SDGs will build upon the Millennium Development Goals (MDG) and replace them by 2015. Even though ensuring environmental sustainability is one of the eight MDG goals, the ocean is not explicitly included. Furthermore, the creation of a comprehensive underlying set of oceanic sustainability indicators would help assessing the current status of marine systems, diagnose on-going trends, and provide information for forward-locking and sustainable ocean governance

Pressure Calculation in Polar and Charged Systems using Ewald Summation: Results for the Extended Simple Point Charge Model of Water

Ewald summation and physically equivalent methods such as particle-mesh Ewald, kubic-harmonic expansions, or Lekner sums are commonly used to calculate long-range electrostatic interactions in computer simulations of polar and charged substances. The calculation of pressures in such systems is investigated. We find that the virial and thermodynamic pressures differ because of the explicit volume dependence of the effective, resummed Ewald potential. The thermodynamic pressure, obtained from the volume derivative of the Helmholtz free energy, can be expressed easily for both ionic and rigid molecular systems. For a system of rigid molecules, the electrostatic energy and the forces at the atom positions are required, both of which are readily available in molecular dynamics codes. We then calculate the virial and thermodynamic pressures for the extended simple point charge (SPC/E) water model at standard conditions. We find that the thermodynamic pressure exhibits considerably less system size dependence than the virial pressure. From an analysis of the cross correlation between the virial and thermodynamic pressure, we conclude that the thermodynamic pressure should be used to drive volume fluctuations in constant-pressure simulations.Comment: RevTeX, 19 pages, 2 EPS figures; in press: Journal of Chemical Physics, 15-August-199

Quantitative CT analysis in patients with pulmonary emphysema: is lung function influenced by concomitant unspecific pulmonary fibrosis?

Purpose: Quantitative analysis of CT scans has proven to be a reproducible technique, which might help to understand the pathophysiology of chronic obstructive pulmonary disease (COPD) and combined pulmonary fibrosis and emphysema. The aim of this retrospective study was to find out if the lung function of patients with COPD with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III or IV and pulmonary emphysema is measurably influenced by high attenuation areas as a correlate of concomitant unspecific fibrotic changes of lung parenchyma. Patients and methods: Eighty-eight patients with COPD GOLD stage III or IV underwent CT and pulmonary function tests. Quantitative CT analysis was performed to determine low attenuation volume (LAV) and high attenuation volume (HAV), which are considered to be equivalents of fibrotic (HAV) and emphysematous (LAV) changes of lung parenchyma. Both parameters were determined for the whole lung, as well as peripheral and central lung areas only. Multivariate regression analysis was used to correlate HAV with different parameters of lung function. Results: Unlike LAV, HAV did not show significant correlation with parameters of lung function. Even in patients with a relatively high HAVof more than 10%, in contrast to HAV (p=0.786) only LAV showed a significantly negative correlation with forced expiratory volume in 1 second (r=−0.309, R2=0.096, p=0.003). A severe decrease of DLCO% was associated with both larger HAV (p=0.045) and larger LAV (p=0.001). Residual volume and FVC were not influenced by LAV or HAV. Conclusion: In patients with COPD GOLD stage III-IV, emphysematous changes of lung parenchyma seem to have such a strong influence on lung function, which is a possible effect of concomitant unspecific fibrosis is overwhelmed

Single spike solutions for strings on S2 and S3

We study solutions for rigidly rotating strings on a two sphere. Among them we find two limiting cases that have a particular interest, one is the already known giant magnon and the other we call the single spike solution. The limiting behavior of this last solution is a string infinitely wrapped around the equator. It differs from that solution by the existence of a single spike of height theta that points toward the north pole. We study its properties and compute its energy E and angular momentum J as a function of theta. We further generalize the solution by adding one angular momentum to obtain a solution on S3. We find a spin chain interpretations of these results in terms of free fermions and the Hubbard model but the exact relation with the same models derived from the field theory is not clear.Comment: LaTeX, 20 pages, 3 figures. v2: Refs adde

Implications of a temperature-dependent magnetic anisotropy for superparamagnetic switching

The macroscopic magnetic moment of a superparamagnetic system has to overcome an energy barrier in order to switch its direction. This barrier is formed by magnetic anisotropies in the material and may be surmounted typically after 10^9 to 10^12 attempts per second by thermal fluctuations. In a first step, the associated switching rate may be described by a Neel-Brown-Arrhenius law, in which the energy barrier is assumed as constant or a given temperature. Yet, magnetic anisotropies in general depend on temperature themselves which is known to modify the Neel-Brown-Arrhenius law. We illustrate quantitatively the implications of a temperature-dependent anisotropy on the switching rate and in particular for the interpretation of the prefactor as an attempt frequency. In particular, we show that realistic numbers for the attempt frequency are obtained when the temperature dependence of the anisotropy is taken into account.Comment: 15 pages, 5 figure

Foundation of Computer (Algebra) ANALYSIS Systems: Semantics, Logic, Programming, Verification

We propose a semantics of operating on real numbers that is sound, Turing-complete, and practical. It modifies the intuitive but super-recursive Blum-Shub-Smale model (formalizing Computer ALGEBRA Systems), to coincide in power with the realistic but inconvenient Type-2 Turing machine underlying Computable Analysis: reconciling both as foundation to a Computer ANALYSIS System. Several examples illustrate the elegance of rigorous numerical coding in this framework, formalized as a simple imperative programming language ERC with denotational semantics for REALIZING a real function $f$: arguments $x$ are given as exact real numbers, while values $y=f(x)$ suffice to be returned approximately up to absolute error $2^p$ with respect to an additionally given integer parameter $p\to-\infty$. Real comparison (necessarily) becomes partial, possibly 'returning' the lazy Kleenean value UNKNOWN (subtly different from $\bot$ for classically undefined expressions like 1/0). This asserts closure under composition, and in fact 'Turing-completeness over the reals': All and only functions computable in the sense of Computable Analysis can be realized in ERC. Programs thus operate on a many-sorted structure involving real numbers and integers, the latter connected via the 'error' embedding $Z\ni p\mapsto 2^p\in R$, whose first-order theory is proven decidable and model-complete. This logic serves for formally specifying and formally verifying correctness of ERC programs