This work presents our understanding of insect wings, and the design and micromachining of artificial wings with golden ratio-based and tapered veins. The geometric anisotwpy of Leading Edge Veins （LEVs） selected by...This work presents our understanding of insect wings, and the design and micromachining of artificial wings with golden ratio-based and tapered veins. The geometric anisotwpy of Leading Edge Veins （LEVs） selected by Diptera has a function able to evade impact. As a Diptera example, the elliptic hollow-LEVs of cranefly wings are mechanically and aerodynamically significant. In this paper, an artificial wing was designed to be a fractal structure by mimicking cranefly wings and incorporating cross-veins and discal cell. Standard technologies of Microelectromechanical Systems （MEMS） were employed to materialize the design using the selected material. One SU-8 wing sample, light and stiffenough to be comparable to fresh cranefly wings, was presented. The as-prepared SU-8 wings are faithful to real wings not only in weight and vein pattern, but also in flexural stiffness and mass distribution. Thus our method renders possible mimickine with good lidelity of natural wings with complex geometry and morphology.展开更多
Conventional orthogonal polynomial approach can solve the multilayered plate only when the material properties of two adjacent layers do not change significantly. This paper de- veloped an improved orthogonal polynomi...Conventional orthogonal polynomial approach can solve the multilayered plate only when the material properties of two adjacent layers do not change significantly. This paper de- veloped an improved orthogonal polynomial approach to solve wave propagation in multilayered plates with very dissimilar material properties. Through numerical comparisons among the exact solution, the results from the conventional polynomial approach and from the improved poly- nomial approach, the validity of the improved polynomial approach is illustrated. Finally, it is shown that the conventional polynomial approach can not yield correct continuous normal stress profiles. The improved orthogonul polynomial approach has overcome this drawback.展开更多
In this paper, the authors propose a new approach to image compression based on the principle of Set Partitioning in Hierarchical Tree algorithm （SPIHT）. Our approach, the modified SPIHT （MSPIHT）, distributes entr...In this paper, the authors propose a new approach to image compression based on the principle of Set Partitioning in Hierarchical Tree algorithm （SPIHT）. Our approach, the modified SPIHT （MSPIHT）, distributes entropy differently than SPIHT and also optimizes the coding. This approach can produce results that are a significant improvement on the Peak Signal-to-Noise Ratio （PSNR） and compression ratio obtained by SPIHT algorithm, without affecting the computing time. These results are also comparable with those obtained using the Embedded Zerotree Wavelet （EZW） and Joint Photographic Experts Group 2000 （JPG2） algorithms.展开更多
In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bou...In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bound on the ZCZ sequences. The performance of the proposed sequences set in asynchronous Direct Sequence-Code Division Multiple Access (DS-CDMA) system is evaluated. In the simulation we used two types of channels: Additive White Gaussian Noise (AWGN) and frequency non-selective fading with AWGN noise. The proposed ternary ZCZ sequence sets show better results, in term of Bit Error Rate (BER), than Hayashi’s ternary ZCZ sequence sets.展开更多
Neural network and genetic algorithms are complementary technologies in the design of adaptive intelligent system. Neural network learns from scratch by adjusting the interconnections betweens layers. Genetic algorith...Neural network and genetic algorithms are complementary technologies in the design of adaptive intelligent system. Neural network learns from scratch by adjusting the interconnections betweens layers. Genetic algorithms are a popular computing framework that uses principals from natural population genetics to evolve solutions to problems. Various forecasting methods have been developed on the basis of neural network, but accuracy has been matter of concern in these forecasts. In neural network methods forecasted values depend to the choose of neural predictor structure, the number of the input, the lag. To remedy to these problem, in this paper, the authors are investing the applicability of an automatic design of a neural predictor realized by real Genetic Algorithms to predict the future value of a time series. The prediction method is tested by using meteorology time series that are daily and weekly mean temperatures in Melbourne, Australia, 1980-1990.展开更多
In this paper, a transmission system based on OFDM (Orthogonal Frequency Division Multiplexing) technique and channel estimation is proposed. The idea is to enhance the assisted channel estimation without data rate lo...In this paper, a transmission system based on OFDM (Orthogonal Frequency Division Multiplexing) technique and channel estimation is proposed. The idea is to enhance the assisted channel estimation without data rate loss. A solution based on frequency diversity is proposed. With the same number of pilots, the global system performances are better for higher mobility speed. The main results will be presented in the case of high mobility context.展开更多
In many classic Ultra Wide Band communication systems, only Gaussian and monocycle pulses associate to PPM modulation are used. In this paper, an original communication system based on orthogonal functions and the Bip...In many classic Ultra Wide Band communication systems, only Gaussian and monocycle pulses associate to PPM modulation are used. In this paper, an original communication system based on orthogonal functions and the Bipolar PPM modulation is proposed. This system allows good performances in terms of Bit Error Rate (BER) and high data rate. This study concerns new applications, such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication systems or a wireless link between computers. These applications need high reliability to transmit security-related information and high data rate to exchange multimedia data. With the emergence of the orthogonal wave-forms, the performances of the UWB communication system will be more interesting in terms of BER and data rate. In this paper, two kinds of improvement are proposed. The first improvement permits us to decrease the Bit Error Rate using the original waveforms. The second allows improving the data rate via novel modulation method. The last parameter study, in this paper, concerns the problem of synchronization between the different users. We will study the performances of the proposed system in multiusers environment in synchronous and asynchronous cases. In the first stage, the theoretical and simulation results will be presented for the proposed system. The simulation results obtained by comparing the classic UWB system and the proposed system show that our solution gives good performances in terms of BER and data rate. The theoretical results of BER values will be given for our proposed solution. In the second stage, we will compute BER values for different jitter effects. Theses studies report theoretical and simulation performances evaluation in the case of two展开更多
This paper studies a new positioning beacon for railway transport using Ultra Wideband (UWB) radio and Time Reversal (TR) techniques. UWB radio has the potential to offer a good level of performance in terms of locali...This paper studies a new positioning beacon for railway transport using Ultra Wideband (UWB) radio and Time Reversal (TR) techniques. UWB radio has the potential to offer a good level of performance in terms of localization accuracy. Time Reversal channel pre-filtering facilitates signal detection and also helps increasing the received energy in the targeted area. In this paper, we evaluate the characteristics of TR technique in terms of temporal focusing. The theoretical and simulation results for Power Delay Profile, equivalent channel model and focusing gain of TR-UWB are given. We analyze the contribution of Time Reversal associated with UWB technology to enhance the localization resolution. The IEEE 802.15.3achannel models are used to evaluate the performance of this system. In terms of localization error, the theoretical and simulation results show that TR-UWB technique delivers improved performance over the UWB localization approach.展开更多
In this paper, continuing with Hu-Li Vrancken and the recent work of Antid Dillen- Schoels-Vrancken, we obtain a decomposition theorem which settled the problem of how to determine whether a given locally strongly con...In this paper, continuing with Hu-Li Vrancken and the recent work of Antid Dillen- Schoels-Vrancken, we obtain a decomposition theorem which settled the problem of how to determine whether a given locally strongly convex aitine hypersurface can be decomposed as a generalized Calabi composition of two affine hyperspheres, based on the properties of its difference tensor K and its affine shape operator S.展开更多
Utilizing oil extracted from waste engine oil and waste plastics, by pyrolysis, as a filel for internal combustion engines has been demonstrated to be one of the best available waste management methods. Separate blend...Utilizing oil extracted from waste engine oil and waste plastics, by pyrolysis, as a filel for internal combustion engines has been demonstrated to be one of the best available waste management methods. Separate blends of fuel from waste engine oil and waste plastic oil was prepared by mixing with diesel and experimental investigation is conducted to study engine performance, combustion and exhaust emissions. It is observed that carbon monoxide （CO） emission increases by 50% for 50% waste plastic oil （50WPO：50D） and by 58% for 50% waste engine oil （50WEO：50D） at full load as compared to diesel. Unburnt hydrocarbon （HC） emission increases by 16% for 50WPO：50D and by 32% for 50WEO：50D as compared to diesel at maximum load. Smoke is fotmd to decrease at all loading conditions for 50WPO：50D operation, but it is comparatively higher for 50WEO：50D operation. 50WPO：50D operation shows higher brake thermal efficiency for all loads as compared to 50WEO：50D and diesel fuel operation. Exhaust gas temperature is higher at all loads tbr 50WPO：50D and 50WEO：50D as compared to diesel fuel operation.展开更多
文摘This work presents our understanding of insect wings, and the design and micromachining of artificial wings with golden ratio-based and tapered veins. The geometric anisotwpy of Leading Edge Veins （LEVs） selected by Diptera has a function able to evade impact. As a Diptera example, the elliptic hollow-LEVs of cranefly wings are mechanically and aerodynamically significant. In this paper, an artificial wing was designed to be a fractal structure by mimicking cranefly wings and incorporating cross-veins and discal cell. Standard technologies of Microelectromechanical Systems （MEMS） were employed to materialize the design using the selected material. One SU-8 wing sample, light and stiffenough to be comparable to fresh cranefly wings, was presented. The as-prepared SU-8 wings are faithful to real wings not only in weight and vein pattern, but also in flexural stiffness and mass distribution. Thus our method renders possible mimickine with good lidelity of natural wings with complex geometry and morphology.
基金supported by the National Natural Science Foundation of China(No.11272115)
文摘Conventional orthogonal polynomial approach can solve the multilayered plate only when the material properties of two adjacent layers do not change significantly. This paper de- veloped an improved orthogonal polynomial approach to solve wave propagation in multilayered plates with very dissimilar material properties. Through numerical comparisons among the exact solution, the results from the conventional polynomial approach and from the improved poly- nomial approach, the validity of the improved polynomial approach is illustrated. Finally, it is shown that the conventional polynomial approach can not yield correct continuous normal stress profiles. The improved orthogonul polynomial approach has overcome this drawback.
文摘In this paper, the authors propose a new approach to image compression based on the principle of Set Partitioning in Hierarchical Tree algorithm （SPIHT）. Our approach, the modified SPIHT （MSPIHT）, distributes entropy differently than SPIHT and also optimizes the coding. This approach can produce results that are a significant improvement on the Peak Signal-to-Noise Ratio （PSNR） and compression ratio obtained by SPIHT algorithm, without affecting the computing time. These results are also comparable with those obtained using the Embedded Zerotree Wavelet （EZW） and Joint Photographic Experts Group 2000 （JPG2） algorithms.
文摘In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bound on the ZCZ sequences. The performance of the proposed sequences set in asynchronous Direct Sequence-Code Division Multiple Access (DS-CDMA) system is evaluated. In the simulation we used two types of channels: Additive White Gaussian Noise (AWGN) and frequency non-selective fading with AWGN noise. The proposed ternary ZCZ sequence sets show better results, in term of Bit Error Rate (BER), than Hayashi’s ternary ZCZ sequence sets.
文摘Neural network and genetic algorithms are complementary technologies in the design of adaptive intelligent system. Neural network learns from scratch by adjusting the interconnections betweens layers. Genetic algorithms are a popular computing framework that uses principals from natural population genetics to evolve solutions to problems. Various forecasting methods have been developed on the basis of neural network, but accuracy has been matter of concern in these forecasts. In neural network methods forecasted values depend to the choose of neural predictor structure, the number of the input, the lag. To remedy to these problem, in this paper, the authors are investing the applicability of an automatic design of a neural predictor realized by real Genetic Algorithms to predict the future value of a time series. The prediction method is tested by using meteorology time series that are daily and weekly mean temperatures in Melbourne, Australia, 1980-1990.
文摘In this paper, a transmission system based on OFDM (Orthogonal Frequency Division Multiplexing) technique and channel estimation is proposed. The idea is to enhance the assisted channel estimation without data rate loss. A solution based on frequency diversity is proposed. With the same number of pilots, the global system performances are better for higher mobility speed. The main results will be presented in the case of high mobility context.
文摘In many classic Ultra Wide Band communication systems, only Gaussian and monocycle pulses associate to PPM modulation are used. In this paper, an original communication system based on orthogonal functions and the Bipolar PPM modulation is proposed. This system allows good performances in terms of Bit Error Rate (BER) and high data rate. This study concerns new applications, such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication systems or a wireless link between computers. These applications need high reliability to transmit security-related information and high data rate to exchange multimedia data. With the emergence of the orthogonal wave-forms, the performances of the UWB communication system will be more interesting in terms of BER and data rate. In this paper, two kinds of improvement are proposed. The first improvement permits us to decrease the Bit Error Rate using the original waveforms. The second allows improving the data rate via novel modulation method. The last parameter study, in this paper, concerns the problem of synchronization between the different users. We will study the performances of the proposed system in multiusers environment in synchronous and asynchronous cases. In the first stage, the theoretical and simulation results will be presented for the proposed system. The simulation results obtained by comparing the classic UWB system and the proposed system show that our solution gives good performances in terms of BER and data rate. The theoretical results of BER values will be given for our proposed solution. In the second stage, we will compute BER values for different jitter effects. Theses studies report theoretical and simulation performances evaluation in the case of two
文摘This paper studies a new positioning beacon for railway transport using Ultra Wideband (UWB) radio and Time Reversal (TR) techniques. UWB radio has the potential to offer a good level of performance in terms of localization accuracy. Time Reversal channel pre-filtering facilitates signal detection and also helps increasing the received energy in the targeted area. In this paper, we evaluate the characteristics of TR technique in terms of temporal focusing. The theoretical and simulation results for Power Delay Profile, equivalent channel model and focusing gain of TR-UWB are given. We analyze the contribution of Time Reversal associated with UWB technology to enhance the localization resolution. The IEEE 802.15.3achannel models are used to evaluate the performance of this system. In terms of localization error, the theoretical and simulation results show that TR-UWB technique delivers improved performance over the UWB localization approach.
基金supported by the Ministry of Science and Technological Development of Serbia,Pro ject174012supported by NSFC(Grant No.11371330)supported by NSFC(Grant Nos.11326072 and 11401173)
文摘In this paper, continuing with Hu-Li Vrancken and the recent work of Antid Dillen- Schoels-Vrancken, we obtain a decomposition theorem which settled the problem of how to determine whether a given locally strongly convex aitine hypersurface can be decomposed as a generalized Calabi composition of two affine hyperspheres, based on the properties of its difference tensor K and its affine shape operator S.
文摘Utilizing oil extracted from waste engine oil and waste plastics, by pyrolysis, as a filel for internal combustion engines has been demonstrated to be one of the best available waste management methods. Separate blends of fuel from waste engine oil and waste plastic oil was prepared by mixing with diesel and experimental investigation is conducted to study engine performance, combustion and exhaust emissions. It is observed that carbon monoxide （CO） emission increases by 50% for 50% waste plastic oil （50WPO：50D） and by 58% for 50% waste engine oil （50WEO：50D） at full load as compared to diesel. Unburnt hydrocarbon （HC） emission increases by 16% for 50WPO：50D and by 32% for 50WEO：50D as compared to diesel at maximum load. Smoke is fotmd to decrease at all loading conditions for 50WPO：50D operation, but it is comparatively higher for 50WEO：50D operation. 50WPO：50D operation shows higher brake thermal efficiency for all loads as compared to 50WEO：50D and diesel fuel operation. Exhaust gas temperature is higher at all loads tbr 50WPO：50D and 50WEO：50D as compared to diesel fuel operation.
