Multi-Agent Distributed Optimization via Inexact Consensus ADMM

Multi-agent distributed consensus optimization problems arise in many signal processing applications. Recently, the alternating direction method of multipliers (ADMM) has been used for solving this family of problems. ADMM based distributed optimization method is shown to have faster convergence rate compared with classic methods based on consensus subgradient, but can be computationally expensive, especially for problems with complicated structures or large dimensions. In this paper, we propose low-complexity algorithms that can reduce the overall computational cost of consensus ADMM by an order of magnitude for certain large-scale problems. Central to the proposed algorithms is the use of an inexact step for each ADMM update, which enables the agents to perform cheap computation at each iteration. Our convergence analyses show that the proposed methods converge well under some convexity assumptions. Numerical results show that the proposed algorithms offer considerably lower computational complexity than the standard ADMM based distributed optimization methods.Comment: submitted to IEEE Trans. Signal Processing; Revised April 2014 and August 201

A Note on Testing ¡°Tax-and-Spend, Spend-and-Tax or Fiscal Synchronization¡±: The Case of China

The hypothesis of tax-and-spend, spend-and-tax, or fiscal synchronization was tested using annual time series data for China over the period 1977 to 1999. We include GDP as a control variable into the model like Baghestani and Mcnown (1994), Koren and Stiassny (1998), and Chang et al. (2002). The results from Granger causality test based on the corresponding multivariate error-correction models (MVECM) suggest feedback between government revenues and government expenditures, supporting the fiscal synchronization hypothesis for China.

On the Employment Effect of Technology: Evidence from US Manufacturing for 1958-1996

Recently, Gali and others find that technological progress may be contractionary: a favorable technology shock reduces hours worked in the short run. We ask whether this observation is robust in disaggregate data. According to our VAR analysis of 458 four-digit U.S. manufacturing industries for 1958-1996, some industries do exhibit temporary reduction in hours in response to a permanent increase in TFP. However, there are far more industries in which technological progress significantly increases hours. Using micro data on average price duration, we ask whether the difference across industries is related to the stickiness of industry-output prices. Among 87 manufacturing goods, we do not find such a relation.Technology Shocks, Hours Fluctuations, Sticky Prices

Switching off the magnetic exchange coupling by quantum resonances

We clarify the role of quantum-well states in magnetic trilayer systems from majority carrier in the ferromagnetic and all carriers in the antiferromagnetic configurations. In addition to numerical and analytic calculations, heuristic pictures are provided to explain effects of a capping layer and side-layer modulation in recent experiments. This immediately offers answers to two unexplained subtle findings in experiments and band-structure calculations, individually. Furthermore, it allows a more flexible tuning of or even turning off the interlayer exchange coupling.Comment: 5 pages, 5 figure

China's Exports and Employment

Dooley et al (2003, 2004a,b,c) argue that China seeks to raise urban employment by 10-12 million persons per year, with about 30% of that coming from export growth. In fact, total employment increased by 7.5-8 million per year over 1997-2005. We estimate that export growth over 1997-2002 contributed at most 2.5 million jobs per year, with most of the employment gains coming from non-traded goods like construction. Exports grew much faster over the 2000-2005 period, which could in principal explain the entire increase in employment. However, the growth in domestic demand led to three-times more employment gains than did exports over 2000-2005, while productivity growth subtracted the same amount again from employment. We conclude that exports have become increasingly important in stimulating employment in China, but that the same gains could be obtained from growth in domestic demand, especially for tradable goods, which has been stagnant until at least 2002.