The Road to Recovery: Fiscal Stimulus, Financial Sector Rehabilitation, and Exit from Policy Easing

The worst of the global financial crisis is probably behind us, but the trajectory to recovery may vary widely across economies. Employing a dynamic structural multi-country model with a financial accelerator, this paper studies the role of three important policy actions in economic recovery: fiscal stimulus, financial sector rehabilitation and exit from policy easing. The main finding is that while both fiscal stimulus and financial sector rehabilitation contribute to economic recovery, the former is likely to be less effective from a medium-term perspective and may generate some negative side effects. This finding suggests that policy priority (of advanced economies in particular) should be on continued financial sector rehabilitation. Moreover, international policy co-ordination is beneficial as it can generate spillovers to regional economies. We also study the effects of over-estimation of the post-crisis potential output by the monetary authorities in advanced economies in their policymaking. We find that this may affect economic recovery in the region through inflationary pressure and the consequent policy tightening.GIMF model; Financial accelerator; Fiscal stimulus; Financial rehabilitation

Shtukas and the Taylor expansion of LL-functions (II)

For arithmetic applications, we extend and refine our results in \cite{YZ} to allow ramifications in a minimal way. Starting with a possibly ramified quadratic extension $F'/F$ of function fields over a finite field in odd characteristic, and a finite set of places $\Sigma$ of $F$ that are unramified in $F'$, we define a collection of Heegner--Drinfeld cycles on the moduli stack of $\mathrm{PGL}_{2}$-Shtukas with $r$-modifications and Iwahori level structures at places of $\Sigma$. For a cuspidal automorphic representation $\pi$ of $\mathrm{PGL}_{2}(\mathbb{A}_{F})$ with square-free level $\Sigma$, and $r\in\mathbb{Z}_{\ge0}$ whose parity matches the root number of $\pi_{F'}$, we prove a series of identities between: (1) The product of the central derivatives of the normalized $L$-functions $\mathcal{L}^{(a)}(\pi, 1/2)\mathcal{L}^{(r-a)}(\pi\otimes\eta, 1/2)$, where $\eta$ is the quadratic id\`ele class character attached to $F'/F$, and $0\le a\le r$; (2) The self intersection number of a linear combination of Heegner--Drinfeld cycles. In particular, we can now obtain global $L$-functions with odd vanishing orders. These identities are function-field analogues of the formulas of Waldspurger and Gross--Zagier for higher derivatives of $L$-functions.Comment: 90 page

China's exporters and importers: firms, products, and trade partners

This paper provides a detailed overview of China's participation in international trade using newly available data on the universe of globally engaged Chinese firms over the 2003-2005 period. We document the distribution of trade flows and product- and trade-partner intensity across both exporting and importing firms and study the relationship between firms' intensive and extensive margins of trade. We also compare trade patterns across firms of different organizational structure, distinguishing between domestic private firms, domestic state-owned firms, foreign-owned firms, and joint ventures. We explore the variation in foreign ownership across sectors, and find results consistent with recent theoretical and empirical work on the role of credit constraints and contractual imperfections in international trade and investment. Finally, we examine the rapid expansion of China's trade over the 2003-2005 period, and decompose it into its extensive and intensive margins. We also use monthly data and study the frequent churning and reallocation of trade flows across firms and across products and trade partners within firms.

Auto-Generation of Pipelined Hardware Designs for Polar Encoder

This paper presents a general framework for auto-generation of pipelined polar encoder architectures. The proposed framework could be well represented by a general formula. Given arbitrary code length $N$ and the level of parallelism $M$, the formula could specify the corresponding hardware architecture. We have written a compiler which could read the formula and then automatically generate its register-transfer level (RTL) description suitable for FPGA or ASIC implementation. With this hardware generation system, one could explore the design space and make a trade-off between cost and performance. Our experimental results have demonstrated the efficiency of this auto-generator for polar encoder architectures

Two-Stream Action Recognition-Oriented Video Super-Resolution

We study the video super-resolution (SR) problem for facilitating video analytics tasks, e.g. action recognition, instead of for visual quality. The popular action recognition methods based on convolutional networks, exemplified by two-stream networks, are not directly applicable on video of low spatial resolution. This can be remedied by performing video SR prior to recognition, which motivates us to improve the SR procedure for recognition accuracy. Tailored for two-stream action recognition networks, we propose two video SR methods for the spatial and temporal streams respectively. On the one hand, we observe that regions with action are more important to recognition, and we propose an optical-flow guided weighted mean-squared-error loss for our spatial-oriented SR (SoSR) network to emphasize the reconstruction of moving objects. On the other hand, we observe that existing video SR methods incur temporal discontinuity between frames, which also worsens the recognition accuracy, and we propose a siamese network for our temporal-oriented SR (ToSR) training that emphasizes the temporal continuity between consecutive frames. We perform experiments using two state-of-the-art action recognition networks and two well-known datasets--UCF101 and HMDB51. Results demonstrate the effectiveness of our proposed SoSR and ToSR in improving recognition accuracy.Comment: Accepted to ICCV 2019. Code: https://github.com/AlanZhang1995/TwoStreamS

Do External Interventions Work? The Case of Trade Reform Conditions in IMF Supported Programs

Trade reform conditions are common in IMF supported programs. Of the 99 countries that had IMF programs during 1993-2003, 77 had conditions on trade reforms in their programs. Since the WTO has not been found especially effective in promoting trade openness for most developing countries, it is of great interest to see if the IMF has been more effective as it combines carrots and sticks not available to the WTO. Yet, the effectiveness of trade conditions in IMF programs has not been systematically studied. Using a unique dataset, this paper provides such an assessment. It finds that trade conditions are associated with an increase in trade openness on average, but the effect comes mostly from countries that, by some measure, have a high degree of "willingness to reform."