Side effects are both the essence and bane of imperative programming. The programmer must carefully coordinate actions to manage their side effects upon each other. Such coordination is complex, error-prone, and fragile. Coherent reaction is a new model of change-driven computation that coordinates effects automatically. State changes trigger events called reactions that in turn change other states. A coherent execution order is one in which each reaction executes before any others that are affected by its changes. A coherent order is discovered iteratively by detecting incoherencies as they occur and backtracking their effects. Unlike alternative solutions, much of the power of imperative programming is retained, as is the common sense notion of mutable state. Automatically coordinating actions lets the programmer express what to do, not when to do it.Coherent reactions are embodied in the Coherence language, which is specialized for interactive applications like those common on the desktop and web. The fundamental building block of Coherence is the dynamically typed mutable tree. The fundamental abstraction mechanism is the virtual tree, whose value is lazily computed, and whose behavior is generated by coherent reactions.

We propose to use the phenomenon of resonant tunneling for the detection of noise. The main idea of this method relies on the effect of homogeneous broadening of the resonant tunneling peak induced by the emission and absorption of collective charge excitations in the measurement circuit. In thermal equilibrium, the signalto-noise ratio of the detector as a function of the detector bandwidth ͑the detector function͒ is given by the universal hyperbolic tangent, which is the statement of the fluctuation-dissipation theorem. The universality breaks down if nonequilibrium processes take place in the measurement circuit. We propose a theory of this phenomenon and make predictions for the detector function in the case when nonequilibrium noise is created by a mesoscopic conductor. We investigate measurement circuit effects and prove the universality of the classical noise detection. Finally, we evaluate the contribution of the third cumulant of current and make suggestions of how it can be measured.

Programmers tend to understand programs by thinking of concrete examples. Example Centric Programming seeks to add IDE support for examples throughout the process of programming. Instead of programmers interpreting examples in their head, the examples are written down and the IDE interprets them automatically.Advanced UI techniques are used to present the results closely integrated with the code. Traditionally distinct programming tools (the editor, Read-Eval-Print-Loop, debugger, and test runner) are unified into a single tool that might be called an example-enlightened editor. This is expected to benefit a wide spectrum of programming activities, for both novice and experienced programmers. Some novel methods for testing and development are made possible. In the longer term, example centrism has implications for the design of future programming languages. A prototype has been implemented for Java in Eclipse.

A type system for object models is described that supports subtyping, unions, and overloading of relation names. No special features need be added to the modelling language; in particular, there are no casts, and the meaning of an object model can be understood without mentioning types. A type error is associated with an expression that can be proved to be irrelevant, in the sense that it can be replaced by an empty set or relation without affecting the value of its enclosing constraint. Relevance is computed by a simple abstract interpretation. This paper has been formatted to meet ACM requirements. A more attractive and legible version is available online at http://sdg.csail. mit.edu/publications.Our type system satisfies an additional criterion:· Sound error reports. Type checking produces no false alarms;an expression reported to be irrelevant is always irrelevant.At the same time, our system makes no guarantees of completeness. Any expression flagged as an error is guaranteed to be vacu-

We discuss the sampling and the volumetric impact of stratigraphic correlation uncertainties in basins and reservoirs. From an input set of wells, we evaluate the probability for two stratigraphic units to be associated using an analog stratigraphic model. In the presence of multiple wells, this method sequentially updates a stratigraphic column defining the stratigraphic layering for each possible set of realizations. The resulting correlations are then used to create stratigraphic grids in three dimensions. We apply this method on a set of synthetic wells sampling a forward stratigraphic model built with Dionisos. To perform cross-validation of the method, we introduce a distance comparing the relative geological time of two models for each geographic position, and we compare the models in terms of volumes. Results show the ability of the method to automatically generate stratigraphic correlation scenarios, and also highlight some challenges when sampling stratigraphic uncertainties from multiple wells.