Flexibly Instructable Agents

This paper presents an approach to learning from situated, interactive tutorial instruction within an ongoing agent. Tutorial instruction is a flexible (and thus powerful) paradigm for teaching tasks because it allows an instructor to communicate whatever types of knowledge an agent might need in whatever situations might arise. To support this flexibility, however, the agent must be able to learn multiple kinds of knowledge from a broad range of instructional interactions. Our approach, called situated explanation, achieves such learning through a combination of analytic and inductive techniques. It combines a form of explanation-based learning that is situated for each instruction with a full suite of contextually guided responses to incomplete explanations. The approach is implemented in an agent called Instructo-Soar that learns hierarchies of new tasks and other domain knowledge from interactive natural language instructions. Instructo-Soar meets three key requirements of flexible instructability that distinguish it from previous systems: (1) it can take known or unknown commands at any instruction point; (2) it can handle instructions that apply to either its current situation or to a hypothetical situation specified in language (as in, for instance, conditional instructions); and (3) it can learn, from instructions, each class of knowledge it uses to perform tasks.Comment: See http://www.jair.org/ for any accompanying file

Convective aggregation in realistic convective-scale simulations

To investigate the real-world relevance of idealized-model convective self-aggregation, five 15-day cases of real organized convection in the tropics are simulated. These include multiple simulations of each case to test sensitivities of the convective organization and mean states to interactive radiation, interactive surface fluxes, and evaporation of rain. These simulations are compared to self-aggregation seen in the same model configured to run in idealized radiative-convective equilibrium. Analysis of the budget of the spatial variance of column-integrated frozen moist static energy shows that control runs have significant positive contributions to organization from radiation and negative contributions from surface fluxes and transport, similar to idealized runs once they become aggregated. Despite identical lateral boundary conditions for all experiments in each case, systematic differences in mean column water vapor (CWV), CWV distribution shape, and CWV autocorrelation lengthscale are found between the different sensitivity runs, particularly for those without interactive radiation, showing that there are at least some similarities in sensitivities to these feedbacks in both idealized and realistic simulations (although the organization of precipitation shows less sensitivity to interactive radiation). The magnitudes and signs of these systematic differences are consistent with a rough equilibrium between 1) equalization due to advection from the lateral boundaries and 2) disaggregation due to the absence of interactive radiation, implying disaggregation rates comparable to those in idealized runs with aggregated initial conditions and non-interactive radiation. This points to a plausible similarity in the way that radiation feedbacks maintain aggregated convection in both idealized simulations and the real world

Experimental and analytical investigation of subsonic longitudinal and lateral aerodynamic characteristics of slender sharp edge 74 deg swept wings

Experimental and analytical study of subsonic longitudinal and lateral aerodynamic characteristics of slender sharp edge 74 deg swept wing

Local Economic Conditions and Wage Labor Decisions of Farm and Rural Nonfarm Couples

Effects of geographical differences in local economic conditions on wage labor demand and wage labor participation decisions of rural couples are examined for Current Population Survey households 1978–82. Wage premiums are shown to exist for localities anticipating labor demand growth, higher unemployment rates, larger share of employment in services, and higher costs of living. These effects are stronger for males than females. Effects of local economic conditions on the probability of wage work are consistent with expected market wage and reservation wage effects, and for farm households the probability of wage work increases when expected farm output prices decline or the wage increases

Neighbour transitivity on codes in Hamming graphs

We consider a \emph{code} to be a subset of the vertex set of a \emph{Hamming graph}. In this setting a \emph{neighbour} of the code is a vertex which differs in exactly one entry from some codeword. This paper examines codes with the property that some group of automorphisms acts transitively on the \emph{set of neighbours} of the code. We call these codes \emph{neighbour transitive}. We obtain sufficient conditions for a neighbour transitive group to fix the code setwise. Moreover, we construct an infinite family of neighbour transitive codes, with \emph{minimum distance} $\delta=4$, where this is not the case. That is to say, knowledge of even the complete set of code neighbours does not determine the code

Improving the Nutrient Content of Food through Genetic Modification: Evidence from Experimental Auctions on Consumer Acceptance

This paper assesses consumers’ acceptance of nutritionally enhanced vegetables using a series of auction experiments administered to a random sample of adult consumers. Evidence suggests that consumers are willing to pay significantly more for fresh produce with labels signaling enhanced levels of antioxidants and vitamin C achieved by moving genes from within the species, as opposed to across species. However, this premium is significantly affected by diverse information treatments injected into the experiments

The Effects of Aerobic vs Anaerobic Exercise on Cognitive Function in College Aged Individuals

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Overview of the Langley subsonic research effort on SCR configuration

Recent advances achieved in the subsonic aerodynamics of low aspect ratio, highly swept wing designs are summarized. The most significant of these advances was the development of leading edge deflection concepts which effectively reduce leading edge flow separation. The improved flow attachment results in substantial improvements in low speed performance, significant delay of longitudinal pitch up, increased trailing edge flap effectiveness, and increased lateral control capability. Various additional theoretical and/or experimental studies are considered which, in conjunction with the leading edge deflection studies, form the basis for future subsonic research effort