Automatic Synthesis of Real Time Systems

This paper presents a method for automatically constructing real time systems directly from their specifications. The model-construction problem is considered for implicit specifications of the form: (A_1 | . . . | A_n | X) sat S where S is a real time (logical) specification, A_1, ... , A_n are given (regular) timed agents and the problem is to decide whether there exists (and if possible exhibit) a real time agent X which when put in parallel with A_1, ..., A_n will yield a network satisfying S. The method presented proceeds in two steps: first, the implicit specification of X is transformed into an equivalent direct specification of X; second, a model for this direct specification is constructed (if possible) using a direct model construction algorithm. A prototype implementation of our method has been added to the real time verification tool EPSILON

Voting when the Stakes are High

Rational choice theories of electoral participation stress that an individual's decision to vote depends on her expected net benefit from doing so. If this instrumental motive is relevant, then turnout should be higher in elections where more is at stake. We test this prediction, by studying how turnout is affected by exogenous variation in governments’ financial flexibility to provide pork for their voters. By utilizing simultaneous elections for different offices, we identify a positive effect of election stakes on turnout.voter motivation, elections, turnout

Extreme morphologies of mantis shrimp larvae

Larvae of stomatopods (mantis shrimps) are generally categorized into four larval types: antizoea, pseudozoea (both representing early larval stages), alima and erichthus (the latter two representing later larval stages). These categories, however, do not reflect the existing morphological diversity of stomatopod larvae, which is largely unstudied. We describe here four previously unknown larval types with extreme morphologies. All specimens were found in the collections of the Zoological Museum, University of Copenhagen and were collected during the Danish Dana Expedition round the world 1928-30. These new larval types all represent erichthus-type larvae, especially differing in their shield morphologies. The shield morphology ranges from almost spherical to rather disc-like, with sometimes extremely elongated spines, but only a general systematic assignment of the larvae was possible. Further investigations of these larvae are crucial to understand their life habits and ecological impact, especially as stomatopod and other crustacean larvae might have a much more important position in the marine ecosystems than their corresponding adults

The Role of Policy Diffusion in Shaping Design Properties

This paper examines the extent to which and how the spread and design of carbon trading systems worldwide have been shaped by international policy diffusion. We highlight eight central design characteristics and identify nine cases for further scrutiny. Focusing on similarities and differences across the cases, we find that international diffusion can explain both converging and diverging designs. While the former observation is in line with the traditional understanding of diffusion leading to convergence as actors adopt a policy initiated by others, it is more striking that policy diffusion stands forth as important for understanding design divergence. Evidence presented in this paper demonstrates that diffusion mechanisms interact with and contribute to the evolution in the policy as it diffuses over time. Hence, we argue that policy convergence is not necessarily a great measure of diffusion because the policy is not the same over time. The policy divergences, partly rooted in different domestic conditions and political constraints, mean that no linked global system is likely in the near future, although the spread of the policy model can be seen as promising for a future emissions trading regime from below

INCORPORATION OF QUANTUM STATISTICAL FEATURES IN MOLECULAR DYNAMICS

We formulate a method for incorporating quantum fluctuations into molecular- dynamics simulations of many-body systems, such as those employed for energetic nuclear collision processes. Based on Fermi's Golden Rule, we allow spontaneous transitions to occur between the wave packets which are not energy eigenstates. The ensuing diffusive evolution in the space of the wave packet parameters exhibits appealing physical properties, including relaxation towards quantum- statistical equilibrium.Comment: 8 latex pages + 1 uuencoded ps figur

Compositional Safety Logics

In this paper we present a generalisation of a promising compositional model-checking technique introduced for finite-state systems by Andersen in [And95] and extended to networks of timedautomata by Larsen et al in [LPY95a, LL95, LPY95b, KLL+97a].In our generalized setting, programs are modelled as arbitrary(possibly infinite-state) transition systems and verified with respectto properties of a basic safety logic. As the fundamentalprerequisite of the compositional technique, it is shown how logicalproperties of a parallel program may be transformed intonecessary and sufficient properties of components of the program.Finally, a set of axiomatic laws are provided useful forsimplifying formulae and complete with respect to validity andunsatisfiability

Specification and Automated Verification of Real-Time Behaviour —A Case Study

In this paper we sketch a method for specification and automaticverification of real-time software properties. The method combinesthe IEC 848 norm and the recent specification techniques TCCS (TimedCalculus of Communicating Systems) and TML (Timed Modal Logic) - supported by an automatic verification tool, Epsilon. The methodis illustrated by modelling a small real-life steam generator example andsubsequent automated analysis of its properties.Keywords: Control system analysis; formal specification; formal verification; real-time systems; standards