Aim To study the influence of radar-target relative speed on frequency MMW high-resolution ore-dimension distance profile and the compensation for it. Methods Based on the distance travelled by the electromagnetic wa...Aim To study the influence of radar-target relative speed on frequency MMW high-resolution ore-dimension distance profile and the compensation for it. Methods Based on the distance travelled by the electromagnetic wave, analyses were made for the compensation algorithm and the expression of the inverse FFT base distance was given.The relative importance of different compensation terms was studied in great detail. The concept of searching compensation was put forward. Results and Condclusion Dcm-△Dvimis the be distance of inverse FFT transformation, the effect caused by the distance △Dim on one-dimension profile is negligible, and the effect caused by the distance Dvim should not be neglected and must be compensated.展开更多
This paper investigates the incentives of invest in improving quality （as opposed to investments in new activities） in the telecommunications industry, based on the example of wireless markets. What is the impact of...This paper investigates the incentives of invest in improving quality （as opposed to investments in new activities） in the telecommunications industry, based on the example of wireless markets. What is the impact of competition on incentives to invest, and on capacities to invest？ What is the role of the rate of penetration and technical progress？ This paper highlights the fact that investment incentives are positively related to potential for technical progress. Investment incentives also depend on market structure, competition intensity, and penetration rate, but not monotonically. This paper consists of a theoretical part which, under assumptions of full market coverage and market share symmetry, shows that for each national market, there is a target level of investment which companies strive to achieve but had not exceeded, and an empirical part that confirms the findings of the theoretical part and explains the differences with the theoretical part by relaxing the assumptions of full coverage and market share symmetry. This target level on the one hand depends on the potential for technical progress and on the other hand, depends on the rate of penetration. From a social perspective, this target level is the best amount that companies are encouraged to invest. Non-achievement of the target level entails underinvestment and a decrease in consumer surplus and welfare and may slow down technical progress. A data set covering 30 countries over a period of eight years is used to empirically prove the existence of a change in investment behavior depending on whether or not the target level is achieved. A low margin per user may hamper achievement of the target level. As a result, maximum consumer surplus and welfare occur under imperfect competition but not under perfect competition.展开更多
China has witnessed rapid economic development since 1978, and during the time, energy production and consumption developed at a tremendous speed as well. Energy efficiency which can be measured by energy consumption ...China has witnessed rapid economic development since 1978, and during the time, energy production and consumption developed at a tremendous speed as well. Energy efficiency which can be measured by energy consumption per unit of GDP, however, experienced continuous decrease. Theoretically, the change of energy efficiency can be attributed to industry structural change and technological change. In order to explain the transformation of Chinese energy efficiency, we adopt logarithmic mean Divisia index techniques to decompose changes in energy intensity in the period of 1994-2005. We find that technological change is the dominant contributor in the decline of energy intensity, but the contribution has declined since 2001. The change in industry structure has decreased the energy intensity before 1998, but raised the intensity after 1998. Decomposed technological effects for all sectors indicate that technological progresses in high energy consuming industries such as raw chemical materials and chemical products, smelting and pressing of ferrous metals, manufacture of non-metallic mineral products and household contribute are the principal drivers of China's declining energy intensity.展开更多
In this paper, it presents a project of a fuzzy controller and a neural estimator to control a coordinate table powered by three-phase induction motor, aiming to implement an intelligent milling system. The position/s...In this paper, it presents a project of a fuzzy controller and a neural estimator to control a coordinate table powered by three-phase induction motor, aiming to implement an intelligent milling system. The position/speed control is performed using vector techniques of three-phase induction machines. The estimation of the motor electromagnetic torque is used for setting the feedrate of the table. The speed control is developed using TS （Takagi-Sugeno） fuzzy logic model and electromagnetic torque estimation using neural network type LMS （least mean square） algorithm. The induction motor is powered by a frequency inverter driven by a DSP （digital signal processor）. Control strategies are implemented in DSP. Simulation results are presented for evaluating the performance of the system.展开更多
Internet search giant Baidu won a second-level prize at the China 2015 National Science and Technology Awards for its technological advancement of machine translation in early January.
In order to further improve the carrier synchronization estimation range and accuracy at low signal-to-noise ratio(SNR), this paper proposes a code-aided carrier synchronization algorithm based on improved nonbinary l...In order to further improve the carrier synchronization estimation range and accuracy at low signal-to-noise ratio(SNR), this paper proposes a code-aided carrier synchronization algorithm based on improved nonbinary low-density parity-check(NB-LDPC) codes to study the polarization-division-multiplexing coherent optical orthogonal frequency division multiplexing(PDM-CO-OFDM) system performance in the cases of quadrature phase shift keying(QPSK) and 16 quadrature amplitude modulation(16-QAM) modes. The simulation results indicate that this algorithm can enlarge frequency and phase offset estimation ranges and enhance accuracy of the system greatly, and the bit error rate(BER) performance of the system is improved effectively compared with that of the system employing traditional NB-LDPC code-aided carrier synchronization algorithm.展开更多
文摘Aim To study the influence of radar-target relative speed on frequency MMW high-resolution ore-dimension distance profile and the compensation for it. Methods Based on the distance travelled by the electromagnetic wave, analyses were made for the compensation algorithm and the expression of the inverse FFT base distance was given.The relative importance of different compensation terms was studied in great detail. The concept of searching compensation was put forward. Results and Condclusion Dcm-△Dvimis the be distance of inverse FFT transformation, the effect caused by the distance △Dim on one-dimension profile is negligible, and the effect caused by the distance Dvim should not be neglected and must be compensated.
文摘This paper investigates the incentives of invest in improving quality （as opposed to investments in new activities） in the telecommunications industry, based on the example of wireless markets. What is the impact of competition on incentives to invest, and on capacities to invest？ What is the role of the rate of penetration and technical progress？ This paper highlights the fact that investment incentives are positively related to potential for technical progress. Investment incentives also depend on market structure, competition intensity, and penetration rate, but not monotonically. This paper consists of a theoretical part which, under assumptions of full market coverage and market share symmetry, shows that for each national market, there is a target level of investment which companies strive to achieve but had not exceeded, and an empirical part that confirms the findings of the theoretical part and explains the differences with the theoretical part by relaxing the assumptions of full coverage and market share symmetry. This target level on the one hand depends on the potential for technical progress and on the other hand, depends on the rate of penetration. From a social perspective, this target level is the best amount that companies are encouraged to invest. Non-achievement of the target level entails underinvestment and a decrease in consumer surplus and welfare and may slow down technical progress. A data set covering 30 countries over a period of eight years is used to empirically prove the existence of a change in investment behavior depending on whether or not the target level is achieved. A low margin per user may hamper achievement of the target level. As a result, maximum consumer surplus and welfare occur under imperfect competition but not under perfect competition.
基金funded by National Science Foundation (Grant No.40535027,40871065)program of Enviromental Education Base of Chinese University Students
文摘China has witnessed rapid economic development since 1978, and during the time, energy production and consumption developed at a tremendous speed as well. Energy efficiency which can be measured by energy consumption per unit of GDP, however, experienced continuous decrease. Theoretically, the change of energy efficiency can be attributed to industry structural change and technological change. In order to explain the transformation of Chinese energy efficiency, we adopt logarithmic mean Divisia index techniques to decompose changes in energy intensity in the period of 1994-2005. We find that technological change is the dominant contributor in the decline of energy intensity, but the contribution has declined since 2001. The change in industry structure has decreased the energy intensity before 1998, but raised the intensity after 1998. Decomposed technological effects for all sectors indicate that technological progresses in high energy consuming industries such as raw chemical materials and chemical products, smelting and pressing of ferrous metals, manufacture of non-metallic mineral products and household contribute are the principal drivers of China's declining energy intensity.
文摘In this paper, it presents a project of a fuzzy controller and a neural estimator to control a coordinate table powered by three-phase induction motor, aiming to implement an intelligent milling system. The position/speed control is performed using vector techniques of three-phase induction machines. The estimation of the motor electromagnetic torque is used for setting the feedrate of the table. The speed control is developed using TS （Takagi-Sugeno） fuzzy logic model and electromagnetic torque estimation using neural network type LMS （least mean square） algorithm. The induction motor is powered by a frequency inverter driven by a DSP （digital signal processor）. Control strategies are implemented in DSP. Simulation results are presented for evaluating the performance of the system.
文摘Internet search giant Baidu won a second-level prize at the China 2015 National Science and Technology Awards for its technological advancement of machine translation in early January.
基金supported by the State Key Program of National Natural Science Foundation of China(No.61431009)the Natural Science Foundation of Shandong Province in China(No.ZR2014AM018)the Shandong Tai-shan Scholar Research Fund
文摘In order to further improve the carrier synchronization estimation range and accuracy at low signal-to-noise ratio(SNR), this paper proposes a code-aided carrier synchronization algorithm based on improved nonbinary low-density parity-check(NB-LDPC) codes to study the polarization-division-multiplexing coherent optical orthogonal frequency division multiplexing(PDM-CO-OFDM) system performance in the cases of quadrature phase shift keying(QPSK) and 16 quadrature amplitude modulation(16-QAM) modes. The simulation results indicate that this algorithm can enlarge frequency and phase offset estimation ranges and enhance accuracy of the system greatly, and the bit error rate(BER) performance of the system is improved effectively compared with that of the system employing traditional NB-LDPC code-aided carrier synchronization algorithm.
