The value-added tax reform puzzle

This explores the impact of a tax reform in some provinces of China which eliminated the value-added tax on some investment goods. While the goal of the experiment was to encourage upgrading of technology, the results suggest that there was no evident increase overall in fixed investment, and employment fell significantly in the treated provinces and sectors. The reform reduced the total number of employees for all types of firms. For domestic firms, it reduced employment by almost 8 percent. The results are robust to a variety of approaches, and suggest that the primary impact of the policy has been to induce labor-saving growth. This experiment has since been extended to the rest of China.Taxation&Subsidies,Investment and Investment Climate,Debt Markets,Emerging Markets,Economic Theory&Research

A STUDY OF ERASURE CORRECTING CODES

This work focus on erasure codes, particularly those that of high performance, and the related decoding algorithms, especially with low computational complexity. The work is composed of different pieces, but the main components are developed within the following two main themes. Ideas of message passing are applied to solve the erasures after the transmission. Efficient matrix-representation of the belief propagation (BP) decoding algorithm on the BEG is introduced as the recovery algorithm. Gallager's bit-flipping algorithm are further developed into the guess and multi-guess algorithms especially for the application to recover the unsolved erasures after the recovery algorithm. A novel maximum-likelihood decoding algorithm, the In-place algorithm, is proposed with a reduced computational complexity. A further study on the marginal number of correctable erasures by the In-place algoritinn determines a lower bound of the average number of correctable erasures. Following the spirit in search of the most likable codeword based on the received vector, we propose a new branch-evaluation- search-on-the-code-tree (BESOT) algorithm, which is powerful enough to approach the ML performance for all linear block codes. To maximise the recovery capability of the In-place algorithm in network transmissions, we propose the product packetisation structure to reconcile the computational complexity of the In-place algorithm. Combined with the proposed product packetisation structure, the computational complexity is less than the quadratic complexity bound. We then extend this to application of the Rayleigh fading channel to solve the errors and erasures. By concatenating an outer code, such as BCH codes, the product-packetised RS codes have the performance of the hard-decision In-place algorithm significantly better than that of the soft-decision iterative algorithms on optimally designed LDPC codes

Superior to one of Glass: Natural Gradient index Lenses via Patchy Particle Self-Assembly

To achieve acute and sensitive vision in a camera-like eye in the ocean, a graded refractive index spherical lens is required to maximize the photon flux on the retina, while leaving an eye structure that fits in the head of an animal. This biological lens must also maintain low protein density fluctuation at the length-scale of a wavelength of visible light in order to maintain transparency. In squids, this sophisticated optical design emerges from the properties of a single protein fold, the S-crystallin. In this thesis, I study the material properties and the self-assembly of the squid lens system. I show that squids have evolved graded index and low density fluctuation in a spherical lens using a suite of proteins that can act as patchy colloids with specific, low valence (M=2 or M=3) with geometric flexibility in bond angles. We conducted small x-ray scattering (SAXS) at different radial positions of the lens, and performed a Monte Carlo simulation to estimate structures consistent with the SAXS result. This analysis suggests that lens proteins may form a gel with gradient density throughout the cellular lens structure, with density mediated by a tightly controlled protein coordination number in each region of the organ. Patchy colloid theory may therefore explain both the graded refractive index lens and the transparency evolved in the lens. I also studied the Chinese century egg, which appears to be a physically analogous system of a protein-based, low-valence patchy colloidal gel that was developed in prehistoric Chinese culinary culture as a method of egg preservation. I compare the structure and material properties of these two systems