Diversity of emergent dynamics in competitive threshold-linear networks: a preliminary report

Threshold-linear networks consist of simple units interacting in the presence of a threshold nonlinearity. Competitive threshold-linear networks have long been known to exhibit multistability, where the activity of the network settles into one of potentially many steady states. In this work, we find conditions that guarantee the absence of steady states, while maintaining bounded activity. These conditions lead us to define a combinatorial family of competitive threshold-linear networks, parametrized by a simple directed graph. By exploring this family, we discover that threshold-linear networks are capable of displaying a surprisingly rich variety of nonlinear dynamics, including limit cycles, quasiperiodic attractors, and chaos. In particular, several types of nonlinear behaviors can co-exist in the same network. Our mathematical results also enable us to engineer networks with multiple dynamic patterns. Taken together, these theoretical and computational findings suggest that threshold-linear networks may be a valuable tool for understanding the relationship between network connectivity and emergent dynamics.Comment: 12 pages, 9 figures. Preliminary repor

WAGE DETERMINATION: PRIVATISED, NEW PRIVATE AND STATE OWNED COMPANIES. EMPIRICAL EVIDENCE FROM PANEL DATA

This paper examines the determinants of wage pressure in large companies, including ownership characteristics and the impact of regional labour markets. By using a panel of 329 Polish largest firms during the period 1997- 2001, we find evidence of rent sharing activities, however there is also asymmetry in quasi rent elasticity of wages. The wage setting mechanism seems to differ between new private companies, privatised companies, state firms and mixed ownership. In particular, wages in state firms are highly responsive to regional labour market conditions, while firms in other sectors are not. Rent sharing is visible in both the state sector and new private companies, yet several specific characteristics differ. On the other hand, quasi rent elasticity appears to be suppressed in privatised companies.http://deepblue.lib.umich.edu/bitstream/2027.42/39970/2/wp584.pd

Power Utility Re-regulation in East European and CIS Transformation Countries (1990-1999): An Institutional Interpretation

This paper analyzes the process of power utility re-regulation in Eastern Europe and the CIS during the decade of systemic transformation (1990-1999); in particular, it explores reasons why early attempts to introduce competition-oriented reform models have not succeeded. We discuss advantages and disadvantages of various reform models from an institutional economic perspective. The approaches to and results of power sector reform in Eastern Europe are assessed; quantitative indicators are wholesale and retail prices, cost coverage ratios, investment levels, and the degree of unbundling and privatization. The paper concludes that a gradual approach to reforms may have been appropriate for the first years of systemic transformation, but that today, ten years later, there is no reason to delay market-oriented reforms any longer.Power sector, institutions, transition, Eastern Europe

Implementing the Affordable Care Act: Key Design Decisions for State-Based Exchanges

The Affordable Care Act requires the establishment of new health insurance marketplaces -- known as exchanges -- in every state by October 1, 2013. This report examines key design decisions made by the 17 states and the District of Columbia that chose to establish a state-based exchange. The analysis finds that states made significant progress in structuring their exchanges, with states varying in their design decisions. Many states expect to exceed some federal requirements -- to collect and display quality data, for instance -- for 2014. These findings suggest that states capitalized on the flexibility provided by the Affordable Care Act to tailor their exchanges to their unique needs and made decisions with an eye towards outcomes, such as enrollment, consumer experience, and sustainability. These findings also suggest that states' initial decisions will inform future exchange implementation and that states will adjust their decisions while continuing to adopt innovative approaches to accomplish policy goals

Exploring efficient neural architectures for linguistic-acoustic mapping in text-to-speech

Conversion from text to speech relies on the accurate mapping from linguistic to acoustic symbol sequences, for which current practice employs recurrent statistical models such as recurrent neural networks. Despite the good performance of such models (in terms of low distortion in the generated speech), their recursive structure with intermediate affine transformations tends to make them slow to train and to sample from. In this work, we explore two different mechanisms that enhance the operational efficiency of recurrent neural networks, and study their performance–speed trade-off. The first mechanism is based on the quasi-recurrent neural network, where expensive affine transformations are removed from temporal connections and placed only on feed-forward computational directions. The second mechanism includes a module based on the transformer decoder network, designed without recurrent connections but emulating them with attention and positioning codes. Our results show that the proposed decoder networks are competitive in terms of distortion when compared to a recurrent baseline, whilst being significantly faster in terms of CPU and GPU inference time. The best performing model is the one based on the quasi-recurrent mechanism, reaching the same level of naturalness as the recurrent neural network based model with a speedup of 11.2 on CPU and 3.3 on GPU.Peer ReviewedPostprint (published version