A Theory of Formal Synthesis via Inductive Learning

Formal synthesis is the process of generating a program satisfying a high-level formal specification. In recent times, effective formal synthesis methods have been proposed based on the use of inductive learning. We refer to this class of methods that learn programs from examples as formal inductive synthesis. In this paper, we present a theoretical framework for formal inductive synthesis. We discuss how formal inductive synthesis differs from traditional machine learning. We then describe oracle-guided inductive synthesis (OGIS), a framework that captures a family of synthesizers that operate by iteratively querying an oracle. An instance of OGIS that has had much practical impact is counterexample-guided inductive synthesis (CEGIS). We present a theoretical characterization of CEGIS for learning any program that computes a recursive language. In particular, we analyze the relative power of CEGIS variants where the types of counterexamples generated by the oracle varies. We also consider the impact of bounded versus unbounded memory available to the learning algorithm. In the special case where the universe of candidate programs is finite, we relate the speed of convergence to the notion of teaching dimension studied in machine learning theory. Altogether, the results of the paper take a first step towards a theoretical foundation for the emerging field of formal inductive synthesis

TRACKING THE GOVERNMENT SECTOR IN A NATURAL RESOURCE-BASED ECONOMY

In this paper, we describe the modeling of a resource-dependent economy, namely, Southeast Alaska, in monitoring the impact of federal, state and local government taxing and spending activities on the region. An important part of the modeling effort is construction of a readily accessible regional database for estimating critical economic relationships and variables that provide a baseline forecast series for the region. The Alaska Interactive Policy Analysis Simulation System (IPASS) makes use of the database in assessing the economic impacts of alternative resource management policies on state and local governments. IPASS is a computer-based, user-interactive economic forecasting and simulation system. The basic system is divided into eight modules: investment; final demand; production; regional export; population; labor force; employment; and primary inputs with government being the ninth module. It provides the quantitative framework for measuring and monitoring changes in regional economic activity and, also, for differentiating among the causal factors accounting for these changes. The individual modules form the IPASS shell that makes possible assessment of the effects of specific government activity on each industry and sector in the region's economy and, in turn, the effects of specific industry activity on each level and function of government.Community/Rural/Urban Development, Public Economics,

The Impact of ISO 9000 Diffusion on Trade and FDI: A New Institutional Analysis

The effects of ISO 9000 diffusion on trade and FDI have gone understudied. We employ panel data reported by OECD nations over the 1995-2002 period to estimate the impact of ISO adoptions on country-pair economic relations. We find ISO diffusion to have no effect in developed nations, but to positively pull FDI (i.e., enhancing inward FDI) and positively push trade (i.e., enhancing exports) in developing nations

GRASS: Generative Recursive Autoencoders for Shape Structures

We introduce a novel neural network architecture for encoding and synthesis of 3D shapes, particularly their structures. Our key insight is that 3D shapes are effectively characterized by their hierarchical organization of parts, which reflects fundamental intra-shape relationships such as adjacency and symmetry. We develop a recursive neural net (RvNN) based autoencoder to map a flat, unlabeled, arbitrary part layout to a compact code. The code effectively captures hierarchical structures of man-made 3D objects of varying structural complexities despite being fixed-dimensional: an associated decoder maps a code back to a full hierarchy. The learned bidirectional mapping is further tuned using an adversarial setup to yield a generative model of plausible structures, from which novel structures can be sampled. Finally, our structure synthesis framework is augmented by a second trained module that produces fine-grained part geometry, conditioned on global and local structural context, leading to a full generative pipeline for 3D shapes. We demonstrate that without supervision, our network learns meaningful structural hierarchies adhering to perceptual grouping principles, produces compact codes which enable applications such as shape classification and partial matching, and supports shape synthesis and interpolation with significant variations in topology and geometry.Comment: Corresponding author: Kai Xu ([email protected]

Vulnerability, Risk, and the Transition to Adulthood

Examines whether poverty and single parenthood influence the likelihood of risk behavior and dropping out among youth and how these behaviors affect the trajectory of connectedness and employment patterns in adulthood. Considers policy implications

The Impact of ISO 9000 Diffusion on Trade and FDI: A New Institutional Analysis

The effects of ISO 9000 diffusion on trade and FDI have gone understudied. We employ panel data reported by OECD nations over the 1995-2002 period to estimate the impact of ISO adoptions on country-pair economic relations. We find ISO diffusion to have no effect in developed nations, but to positively pull FDI (i.e., enhancing inward FDI) and positively push trade (i.e., enhancing exports) in developing nations. ZUSAMMENFASSUNG - (Der Einfluss der Verbreitung des ISO 9000 Standards auf Außenhandel und ausländische Direktinvestitionen: eine neue institutionelle Analyse) Die Folgen der Verbreitung des ISO 9000 Standards auf den Außenhandel und ausländische Direktinvestitionen wurden bislang noch nicht ausreichend untersucht. In diesem Papier werden Datensätze von OECD-Mitgliedsstaaten im Zeitraum von 1995 - 2002 verwendet, um die Auswirkung von ISO-Einführungen auf bilaterale Außenhandelsaktivitäten zu untersuchen. Es zeigt sich, dass die Anwendung der ISO-Norm keine Auswirkungen auf den Handel zwischen entwickelten Ländern hat. In Entwicklungsländern dagegen führt die Einführung der ISO 9000 Norm dazu, dass die ins Land geholten ausländischen Direktinvestitionen (FDI) steigen und dass der Außenhandel - messbar an der Steigerung des Exportvolumens - positiv beeinflusst wird.FDI, Trade, Transaction Costs, Institutions