Can market-clearing models explain U.S. labor market fluctuations?

Throughout the past two decades, market-clearing models of the business cycle have been praised for their ability to explain key empirical features of the post-war U.S. business cycle. Real business cycle (RBC) theory shows that in a model grounded in microeconomic foundations, disturbances to national productivity can explain how aggregate variables such as GDP, consumption and investment behave over time, relative to each other. One of the primary weaknesses of the standard RBC model, however, is its inability to account for some important aspects of U.S. labor market fluctuations. In this article, Victor E. Li summarizes important U.S. business cycle facts and examines how and why these market-clearing models have so much difficulty explaining the mannner in which these facts pertain to the labor market. Li then develops a simple market-clearing framework that demonstrates how a more realistic treatment of unemployment and incomplete risk-sharing may provide an alternative approach to better account for these labor market facts. In particular, Li looks at the situation where the risk of being unemployed cannot be completely shared across all individuals when there are unexpected aggregate economic shocks.Business cycles ; Labor market ; Econometric models

Crustal deformation along the San Andreas, California

The goal is to achieve a better understanding of the regional and local deformation and crustal straining processes in western North America, particularly the effects of the San Andreas and nearby faults on the spatial and temporal crustal deformation behavior. Construction of theoretical models based on the mechanics of coupled elastic plate, viscoelastic foundation and large scale crack mechanics provide a rational basis for the interpretation of seismic and aseismic anomalies and expedite efforts in forecasting the stability of plate boundary deformation. Special focus is placed on the three dimensional time dependent surface deformation due to localized slippage in a elastic layer coupled to a visco-elastic substrate. The numerical analysis is based on a 3-D boundary element technique. Extension to visco-elastic coupling demands the derivation of 3-D time dependent Green's function. This method was applied to analyze the viscoelastic surface displacements due to a dislocated embedded patch. Surface uplift as a function of time and position are obtained. Comparisons between surface uplift for long and short dislocated patches are made

Strain accumulation and surface deformation along the San Andreas, California

The goal of this project remains to be the achievement of a better understanding of the regional and local deformation and crustal straining processes in western North America, particularly the effect of the San Andreas and nearby faults on the spatial and temporal crustal deformation behavior. Construction of theoretical models based on the mechanics of coupled elastic plate/viscoelastic foundation and large scale crack mechanics provide a rational basis for the interpretation of seismic and aseismic anomalies and expedite efforts in forecasting the stability of plate boundary deformations. In the present period, special focus is placed on the 3-D effect of irregular fault locked patches on the ground measured deformation fields. Specifically, use is made of a newly developed 3-D boundary element program to analyze the fault slip and vertical ground motion in the Parkfield area on the San Andreas

Strain accumulation and surface deformation along the San Andreas, California

Stressing and rupture of a locked zone adjacent to a creeping fault segment was studied with special reference to strength heterogeneity depthwise and along-strike. The resulting precursory temporal and spatial variations of surface strain rate profiles were compared to geodetic measurements on the San Andreas fault in central California. Crustal deformation in great California earthquake cycles was also studied with special reference to the temporal decay of strain rate observed since the 1957 and 1906 great earthquakes, and comtemporary surface strain rate and velocity profiles at several locations along the San Andreas. The effect of viscoelastic response in the deep aseismic shear zone on the surface deformation behavior was examined. Work was begun on a fundamental reformulation of the crustal deformation problem focusing on the crustal deformation process affected by deep aseismic slip as the slip zone progresses toward an instability and as deep seismic slip continues postseismically, the 3-D nature of the problem due to geometry and material heterogeneity, and the time-dependent source coming from the lithosphere/astenospheric coupling process

Inside Money, Credit, and Investment

This paper presents a monetary explanation for several business-cycle facts: (i) household and business investment are procyclical, (ii) business investment lags household investment, (iii) household investment is positively correlated with M1, and (iv) household credit outstanding is positively correlated with and more volatile than household investment. We develop a dynamic general equilibrium model that features financial intermediaries accepting deposits and providing loans, credit-producing firms, and inside (bank-created) money. It is shown that the transmission of monetary shocks facilitated by credit and inside money creation is able to reconcile these real and monetary observations regarding the cyclical behavior of investment.

Efficient Learning for Undirected Topic Models

Replicated Softmax model, a well-known undirected topic model, is powerful in extracting semantic representations of documents. Traditional learning strategies such as Contrastive Divergence are very inefficient. This paper provides a novel estimator to speed up the learning based on Noise Contrastive Estimate, extended for documents of variant lengths and weighted inputs. Experiments on two benchmarks show that the new estimator achieves great learning efficiency and high accuracy on document retrieval and classification.Comment: Accepted by ACL-IJCNLP 2015 short paper. 6 page