A Comparative Study of Coq and HOL

This paper illustrates the differences between the style of theory mechanisation of Coq and of HOL. This comparative study is based on the mechanisation of fragments of the theory of computation in these systems. Examples from these implementations are given to support some of the arguments discussed in this paper. The mechanisms for specifying definitions and for theorem proving are discussed separately, building in parallel two pictures of the different approaches of mechanisation given by these systems

Success factors for farming collectives

As the most intensive form of partnership in agriculture, farming collectives (FCs) place high demands on their participants. Based on a census of Swiss farming collectives, three success indicators are formed. The first and second describe interpersonal and economic success respectively, whilst the third encompasses overall success. Factors influencing success are determined by means of multiple regressions. Five predictor variables (compatibility with co-operation partner, trust, information quality, attitude of social environment, and relationship/kinship circle of the cooperation partner) accounted for 44 per cent of the variance in interpersonal success. Economic success was far more difficult to explain (R2 = 0.11). Even so, the influence of “soft” factors, even on the economic success of a farming collective, is striking. Above all, trust and the human and structural compatibility of the cooperation partners play an important role for all three types of success. The co-operation agreement, agricultural consultation, the number of participating people on the farm, and the investments made may be ranked as less important than previously assumed.farming collective, economic satisfaction, interpersonal conflicts, Agribusiness,

Construction and Application of an LP Farm Model with an Integrated Life Cycle Assessment for the Determination of Sustainable Milk Production Systems

The increasingly stringent conditions underlying Swiss dairy production demand sustainable milk production systems that are economically optimized but also meet the ecological requirements of society. To determine such systems, a comparative-static LP model was constructed at farm level. Realistic production systems are reproduced in the model by means of binary variables. An Life Cycle Assessment (LCA) was integrated into the model to determine the environmental impacts of the farm. To this effect, the internal farm influences on production are illustrated in detail. An initial application of the model, in which a comparison of different income-optimized production systems was carried out, revealed some goal conflicts between economics and ecology. Systems involving full-time grazing achieved the best results in both aspects.Life Cycle Assessment (LCA), LP-model, dairy production, production system, Livestock Production/Industries, C61, Q12, Q51,

Techno-ökonomische Bewertung von Stromspeichern im Niederspannungsnetz

Dieses Working Paper basiert auf der Diplomarbeit Techno-ökonomische Bewertung von Stromspeichern im Niederspannungsnetz und bildet eine Zusammenfassung der wesentlichen Aspekte dieser Arbeit. Darüber hinaus wurden Informationen aus späteren Veröffentlichungen aufgenommen. In der Diplomarbeit wird die Rolle von Stromspeichern im Niederspannungsnetz unter technischen und ökonomischen Gesichtspunkten betrachtet. Durch die zunehmende Einspeisung von Strom aus erneuerbaren Energieträgern in das Verteilnetz kann es zu Situationen von Netzüberlastungen kommen, da Verteilnetze für diesen Fall nicht ausgelegt wurden. Es werden deshalb Maßnahmen notwendig, um diese Netzüberlastungen zu vermeiden. Eine Möglichkeit ist der Netzausbau. Da dieser mit hohen Investitionen verbunden ist, werden günstigere Alternativen gesucht. In der Diplomarbeit wird der Speicher als mögliche Alternative genauer untersucht. Der Kern der Arbeit bildet daher die Simulation eines Niederspannungsreferenznetzes, in das verschiedene Batteriespeichertypen integriert werden. In diesem Working Paper werden zunächst wesentliche Erkenntnisse verschiedener Studien zusammengestellt, die sich mit der Überlastung im Verteilnetz bzw. im Niederspannungsnetz beschäftigen und Rückschlüsse auf einen möglichen Speicherbedarf zulassen. Ein weiterer Abschnitt erläutert die Vorgehensweise bei der Modellierung und Simulation des Niederspannungsnetzes. Abschließend werden die Ergebnisse der Simulation und der Wirtschaftlichkeitsbetrachtung vorgestellt, und die Arbeit wird kritisch gewürdigt

Quantum-noise quenching in atomic tweezers

The efficiency of extracting single atoms or molecules from an ultracold bosonic reservoir is theoretically investigated for a protocol based on lasers, coupling the hyperfine state in which the atoms form a condensate to another stable state, in which the atom experiences a tight potential in the regime of collisional blockade, the quantum tweezers. The transfer efficiency into the single-atom ground state of the tight trap is fundamentally limited by the collective modes of the condensate, which are thermally and dynamically excited. The noise due to these excitations can be quenched for sufficiently long laser pulses, thereby achieving high efficiencies. These results show that this protocol can be applied for initializing a quantum register based on tweezer traps for neutral atoms.Comment: 4+ pages, 3 figures, revised version. To appear in Phys. Rev. A (Rapid

Multiplicative Noise: Applications in Cosmology and Field Theory

Physical situations involving multiplicative noise arise generically in cosmology and field theory. In this paper, the focus is first on exact nonlinear Langevin equations, appropriate in a cosmologica setting, for a system with one degree of freedom. The Langevin equations are derived using an appropriate time-dependent generalization of a model due to Zwanzig. These models are then extended to field theories and the generation of multiplicative noise in such a context is discussed. Important issues in both the cosmological and field theoretic cases are the fluctuation-dissipation relations and the relaxation time scale. Of some importance in cosmology is the fact that multiplicative noise can substantially reduce the relaxation time. In the field theoretic context such a noise can lead to a significant enhancement in the nucleation rate of topological defects.Comment: 21 pages, LaTex, LA-UR-93-210