Function Verification of Combinational Arithmetic Circuits

Hardware design verification is the most challenging part in overall hardware design process. It is because design size and complexity are growing very fast while the requirement for performance is ever higher. Conventional simulation-based verification method cannot keep up with the rapid increase in the design size, since it is impossible to exhaustively test all input vectors of a complex design. An important part of hardware verification is combinational arithmetic circuit verification. It draws a lot of attention because flattening the design into bit-level, known as the bit-blasting problem, hinders the efficiency of many current formal techniques. The goal of this thesis is to introduce a robust and efficient formal verification method for combinational integer arithmetic circuit based on an in-depth analysis of recent advances in computer algebra. The method proposed here solves the verification problem at bit level, while avoiding bit-blasting problem. It also avoids the expensive Groebner basis computation, typically employed by symbolic computer algebra methods. The proposed method verifies the gate-level implementation of the design by representing the design components (logic gates and arithmetic modules) by polynomials in Z2n . It then transforms the polynomial representing the output bits (called “output signature”) into a unique polynomial in input signals (called “input signature”) using gate-level information of the design. The computed input signature is then compared with the reference input signature (golden model) to determine whether the circuit behaves as anticipated. If the reference input signature is not given, our method can be used to compute (or extract) the arithmetic function of the design by computing its input signature. Additional tools, based on canonical word-level design representations (such as TED or BMD) can be used to determine the function of the computed input signature represents. We demonstrate the applicability of the proposed method to arithmetic circuit verification on a large number of designs

Exchange Rate Misalignments: Historical Experience of Japan, Germany, Singapore and Taiwan Compared to China Today

This is a comparative study on the historical experience of real effective exchange rate (REER) misalignment of Japanese yen, Deutsche mark, Singapore dollar and Taiwan dollar, with regard to the recent dispute over the Renminbi (RMB) valuation. Panel-based misalignment estimates of the four economies show that net foreign asset build-up does not necessarily result in currency misalignment, and the recent misalignment of RMB is not unprecedented in terms of magnitude, duration or currency coverage, whereas volatility in REER misalignment is likely to propagate to inflation of the home economy concerned. The assertion of 'RMB rate manipulation' thus lacks empirical support.REER misalignment, RMB, Yen, D-mark, Singapore dollar, Taiwan dollar

Exchange rate misalignments: A comparison of China today against recent historical experiences of Japan, Germany, Singapore and Taiwan

The familiar claim of Chinese currency manipulation is generally asserted without reference to empirical evidence. To investigate the legitimacy of the claim, we ask if the undervalued misalignment found in the real effective exchange rate (REER) of the Chinese renminbi (RMB) over the past decade has any recent historical precedents. Four cases are examined: the Japanese yen, the Deutsche mark, the Singapore dollar and the Taiwan dollar. Panel-based misalignment estimates of the REER of the four currencies are obtained using quarterly data from the late 1970s to the early 2000s. Our estimates suggest that there are precedents to the recent misalignment of the RMB in terms of magnitude, duration or breadth of currency coverage, and that a net build-up in foreign asset does not necessarily result in currency misalignment. In addition to finding little empirical justification for the claim of Chinese currency manipulation, we note that REER misalignment runs a risk of propagating inflation in the home economy.REER misalignment; RMB; yen; D-mark; Singapore dollar; Taiwan dollar

Quantitative Assessment of Flame Stability Through Image Processing and Spectral Analysis

This paper experimentally investigates two generalized methods, i.e., a simple universal index and oscillation frequency, for the quantitative assessment of flame stability at fossil-fuel-fired furnaces. The index is proposed to assess the stability of flame in terms of its color, geometry, and luminance. It is designed by combining up to seven characteristic parameters extracted from flame images. The oscillation frequency is derived from the spectral analysis of flame radiation signals. The measurements involved in these two methods do not require prior knowledge about fuel property, burner type, and other operation conditions. They can therefore be easily applied to flame stability assessment without costly and complex adaption. Experiments were carried out on a 9-MW heavy-oil-fired combustion test rig over a wide range of combustion conditions including variations in swirl vane position of the tertiary air, swirl vane position of the secondary air, and the ratio of the primary air to the total air. The impact of these burner parameters on the stability of heavy oil flames is investigated by using the index and oscillation frequency proposed. The experimental results obtained demonstrate the effectiveness of the methods and the importance of maintaining a stable flame for reduced NOx emissions. It is envisaged that such methods can be easily transferred to existing flame closed-circuit television systems and flame failure detectors in power stations for flame stability monitoring

Income Disparity and Economic Growth: Evidence from China

This paper carries out a pilot empirical study on how income inequality affects growth and the macro economy by means of incorporating panel data information into a macro-econometric model. China is used as the pilot field. Provincial urban and rural household data are used to construct inequality measures, which are then used to augment household consumption equations in the ADB China model. Model simulations are performed to study the effect of inequality on GDP growth and its sectoral components. Results show that inequality is a robust explanatory variable of consumption and that the way inequality develops over time carries certain negative consequences on GDP and sectoral growth.Income inequality, Growth, Econometric model, China