Control Scheme of Spread Frequency Band for High Power Impedance Measuring Converter with Chirp Signal Injection

Impedance measurement is an effective solution for evaluating stability of a power system with high penetration of renewable sources.In this paper,the impedance measurement is achieved by a typical high-power impedance measuring converter(HPIM-converter)with chirp signal injection.The modulation saturation phenomenon of the HPIM-converter is revealed,and the frequency sweep boundary is analyzed in detail.To expand the rated frequency range of the HPIM-converter,a spread frequency band control scheme based on an over-modulation technique is proposed in this paper.The proposed control method enlarges the rated frequency band and can inject a disturbance voltage into the system under test with consistent amplitude in the rated frequency band.Also,a smooth transition strategy between linear modulation mode and over-modulation mode is proposed for suppressing signal fluctuation.Finally,the effectiveness of the proposed method is verified by simulation tests.

Automatic LOD selection using viewpoint entropy

Discrete Level of Detail (LOD) strategy is an effective solution for balancing the inherentcontradiction between quality and speed in computer graphics. However, application ofthis strategy requires both the appropriate selection approach and the visually comfortable transition procedure to reduce the popping effects introduced by switching betweendifferent levels. In this paper, a novel automatic LOD selection method based on viewpoint entropy was proposed. Firstly, the traditional calculation method of viewpointentropy contained in a scene was improved for the preprocessing of LOD models. Then,the runtime rendering scheme combined with our selection method was designed forbalance of frame rate during real-time rendering, and a novel smoothing LOD transitionstrategy based on Alternate Frame Rendered (ALR) was put forward for eliminationof popping effects. Finally, an example of complex scene combined with our proposalwas researched to verify its real-time performance and ability in holding continuity ofrendered images. Experimental studies show the effectiveness for stabilizing frame rateand improvements in reducing loss of continuity.

Energy Consumption, Economic Development and Temperature in China： Evidence from PSTR Model

Since the 1980s, the Chinese economy has developed rapidly, with an av- erage annual growth rate around 10%. Energy consumption in China has greatly in- creased as well. This paper investigates the relationship between energy consumption, economic development and temperature in China by adopting provincial panel data from 1990 to 2011. Different from existing studies, in this paper, we use a panel smooth transition regression （PSTR） model to estimate the non-linearity relationship. Four different threshold variables including two lagged endogenous variables and two important exogenous variables have been considered. We find that energy intensity and the ratio of gross capital formation are suitable for the non-linearity model. The estimated elasticities of time dynamic indicate that energy consumption is income in- elastic and temperature inelastic. Elasticities of real income at first increase and then decrease, however, elasticities of temperature gradually increase after the year 1993. Last of all, we propose some policy implications.