For an n-variable logic function,the power dissipation and area of the REED-MULLER （RM） circuit corresponding to each polarity are different. Based on the propagation algorithm of signal probability,the decompositio...For an n-variable logic function,the power dissipation and area of the REED-MULLER （RM） circuit corresponding to each polarity are different. Based on the propagation algorithm of signal probability,the decomposition algorithm of a multi-input XOR/AND gate,and the multiple segment algorithm of polarity conversion,this paper successfully applies the whole annealing genetic algorithm （WAGA） to find the best polarity of an RM circuit. Through testing eight large-scale circuits from the Microelectronics Center North Carolina （MCNC） Benchmark, the SYNOPSYS synthesis results show that the RM circuits corresponding to the best polarity found using the proposed algorithm attain average power,area,and max delay savings of 77.2% ,62.4% ,and 9.2% respectively,compared with those under polarity 0.展开更多
Accuracy of time-depth conversion in data processing of transient electromagnetic prospecting always affects the accu- rate positioning of water bodies in coal mines. In order to improve the accuracy of time-depth con...Accuracy of time-depth conversion in data processing of transient electromagnetic prospecting always affects the accu- rate positioning of water bodies in coal mines. In order to improve the accuracy of time-depth conversion, we established a mathe- matical model of time-depth conversion for a transient electromagnetic method based on the theory of "double smoke ring effect" of full space transient electromagnetic field transmission. Using a 3-layer as well as a 4-layer geo-electric model for roadway floors, we performed the time-depth conversion of theoretical curves of apparent resistance varying over time. In these curves, the depth corresponding to extreme value points is nearly the same as the depth of a geo-electric model. The position of water body deter- mined by our time-depth conversion method agrees well with the result of borehole drilling, indicating that the established time-depth conversion model can clearly improve the accuracy of spatial positioning of water bodies in coal mines.展开更多
Characterizing the petrophysical properties holds significant importance in shale oil reservoirs.Twodimensional(2-D)nuclear magnetic resonance(NMR),a nondestructive and noninvasive technique,has numerous applications ...Characterizing the petrophysical properties holds significant importance in shale oil reservoirs.Twodimensional(2-D)nuclear magnetic resonance(NMR),a nondestructive and noninvasive technique,has numerous applications in petrophysical characterization.However,the complex occurrence states of the fluids and the highly non-uniform distributions of minerals and organic matter pose challenges in the NMR-based petrophysical characterization.A novel T_(1)-T_(2)relaxation theory is introduced for the first time in this study.The transverse and longitudinal relaxivities of pore fluids are determined based on numerical investigation and experimental analysis.Additionally,an improved random walk algorithm is proposed to,on the basis of digital shale core,simulate the effects of the hydrogen index(HI)for the organic matter,echo spacing(T_(E)),pyrite content,clay mineral type,and clay content on T_(1)-T_(2)spectra at different NMR frequencies.Furthermore,the frequency conversion cross-plots for various petrophysical parameters influenced by the above factors are established.This study provides new insights into NMRbased petrophysical characterization and the frequency conversion of petrophysical parameters measured by laboratory NMR instruments and NMR logging in shale oil reservoirs.It is of great significance for the efficient exploration and environmentally friendly production of shale oil.展开更多
There are rich natural gas resources in the northwestern South China Sea deepwater areas, with poor degree of exploration. Because of the unique tectonic, sedimentary background of the region, velocity model building ...There are rich natural gas resources in the northwestern South China Sea deepwater areas, with poor degree of exploration. Because of the unique tectonic, sedimentary background of the region, velocity model building and time-depth conversion have been an important and difficult problem for a long time. Recent researches in this direction have revealed three major problems for deepwater areas, i.e., the way to determine error correction for drilling velocity, the optimization of velocity modeling, and the understanding and analysis of velocity variations in the slope areas. The present contribution proposes technical solutions to the problems：（1） velocity correction version can be established by analyzing the geology, reservoir, water depths and velocity spectrum characteristics;（2） a unified method can be adopted to analyze the velocity variation patterns in drilled pale structural positions;and （3） across-layer velocity is analyzed to establish the velocity model individually for each of the layers. Such a solution is applicable, as shown in an example from the northwestern South China Sea deepwater areas, in which an improved prediction precision is obtained.展开更多
This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generat...This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.展开更多
The generation of electricity,considering environmental and eco-nomic factors is one of the most important challenges of recent years.In this article,a thermoelectric generator(TEG)is proposed to use the thermal energ...The generation of electricity,considering environmental and eco-nomic factors is one of the most important challenges of recent years.In this article,a thermoelectric generator(TEG)is proposed to use the thermal energy of an electric water heater(EWH)to generate electricity independently.To improve the energy conversion efficiency of the TEG,a fuzzy logic con-troller(FLC)-based perturb&observe(P&O)type maximum power point tracking(MPPT)control algorithm is used in this study.An EWH is one of the major electricity consuming household appliances which causes a higher electricity price for consumers.Also,a significant amount of thermal energy generated by EWH is wasted every day,especially during the winter season.In recent years,TEGs have been widely developed to convert surplus or unused thermal energy into usable electricity.In this context,the proposed model is designed to use the thermal energy stored in the EWH to generate electricity.In addition,the generated electricity can be easily stored in a battery storage system to supply electricity to various household appliances with low-power-consumption.The proposed MPPT control algorithm helps the system to quickly reach the optimal point corresponding to the maximum power output and maintains the system operating point at the maximum power output level.To validate the usefulness of the proposed scheme,a study model was developed in the MATLAB Simulink environment and its performance was investigated by simulation under steady state and transient conditions.The results of the study confirmed that the system is capable of generating adequate power from the available thermal energy of EWH.It was also found that the output power and efficiency of the system can be improved by maintaining a higher temperature difference at the input terminals of the TEG.Moreover,the real-time temperature data of Abha city in Saudi Arabia is considered to analyze the feasibility of the proposed system for practical implementation.展开更多
A voice conversion algorithm,which makes use of the information between continuous frames of speech by compressed sensing,is proposed in this paper.According to the sparsity property of the concatenated vector of seve...A voice conversion algorithm,which makes use of the information between continuous frames of speech by compressed sensing,is proposed in this paper.According to the sparsity property of the concatenated vector of several continuous Linear Spectrum Pairs（LSP）in the discrete cosine transformation domain,this paper utilizes compressed sensing to extract the compressed vector from the concatenated LSPs and uses it as the feature vector to train the conversion function.The results of evaluations demonstrate that the performance of this approach can averagely improve 3.21%with the conventional algorithm based on weighted frequency warping when choosing the appropriate numbers of speech frame.The experimental results also illustrate that the performance of voice conversion system can be improved by taking full advantage of the inter-frame information,because those information can make the converted speech remain the more stable acoustic properties which is inherent in inter-frames.展开更多
Conversion of the Reed–Muller（RM） expansion between two different polarities is an important step in the synthesis and optimization of RM circuits. By investigating XOR decomposition, a new conversion algorithm is ...Conversion of the Reed–Muller（RM） expansion between two different polarities is an important step in the synthesis and optimization of RM circuits. By investigating XOR decomposition, a new conversion algorithm is proposed to convert MPRM expansion from one polarity to another. First, the relationship between XOR decomposition and mixed polarity is set up. Second, based on this, the operation relation of term coefficients between the two polarities is derived to realize MPRM expansion conversion. And finally, with the MCNC Benchmark, the resultsofouralgorithmshowthatitismoresuitablefordealingwithMPRMexpansionwithmoreterms.Compared to the previous tabular technique, the conversion efficiency is improved up to approximately 44.39%.展开更多
为探究高比例可再生能源系统下风光资源的消纳与多元化利用途径,提出一种电氨转换及风光时空相关性的多能耦合系统两阶段鲁棒优化模型。首先分析了电制氨的运行机制,并结合直接氨燃料电池技术,探讨了电制氨与氨燃料电池协同运行的系统...为探究高比例可再生能源系统下风光资源的消纳与多元化利用途径,提出一种电氨转换及风光时空相关性的多能耦合系统两阶段鲁棒优化模型。首先分析了电制氨的运行机制,并结合直接氨燃料电池技术,探讨了电制氨与氨燃料电池协同运行的系统特性。为综合考虑风光出力的相关性与不确定性并选择最相近极限场景,该文采用最小体积封闭椭球算法构建高维椭球集,并通过1-范数和∞-范数建立风光出力场景的概率分布置信集,有效整合风光出力不确定性的分布信息。针对鲁棒优化模型中二元变量导致计算时间较长问题,该文提出了一种改进列与约束生成(column and constraint generation,C&CG)算法,利用三分块-交替方向乘子法和近似凸化方法分别处理主-子问题,并通过非精确C&CG算法对主-子问题进行迭代求解,在确保计算效率的同时,快速逼近最优解。结果表明,所提模型获取的极限场景能够准确捕捉风光出力的时空相关性及不确定性,电-氨转换系统有效促进了可再生能源的合理消纳,在确保系统安全稳定运行的同时,显著提升了调度经济性及求解效率。展开更多
As the well drilling depth has broken through the 10,000 m in China,accurate measurements of downhole engineering parameters,such as annulus temperature and pressure for the whole wellbore,are significant in controlli...As the well drilling depth has broken through the 10,000 m in China,accurate measurements of downhole engineering parameters,such as annulus temperature and pressure for the whole wellbore,are significant in controlling potential downhole complexities.In this present work,a new micro-measurer is developed by integrating measurements of downhole temperature,pressure,magnetic field strength,and its own dynamic signals.The micro-measurer can flow with drilling fluid from the drillstring to the bottomhole and then float up back to the ground via the wellbore annulus.Compared with other downhole measurement tools that are fixedly connected to the drill string,its“measure-and-move-on”approach reduces the residence time in the high-temperature and high-pressure zone at the bottomhole;moreover,both the pressure and temperature at different well depth can be measured,thereby the temperature and pressure profiles of the whole wellbore can be constructed.In addition,the bluetooth low energy(BLE)technique is applied to offer the micro-measurer with the capability of wireless information transmission;while hydrodynamic optimization of the micro-measurer is carried out to design the structure of the micro-measurer,which can promote its recovery rate from downhole.In addition,an intelligent joint for releasing micro-measurers from the wellbore annulus is also proposed,aiming to overcome the limitation imposed by the nozzle on the size of the micro-measurer.Both the indoor experiments and the field tests have verified the feasibility of the newly designed micro-measurer,which is a key step for establishing a complete downhole internet of things(IoT)system to serve the intelligent drilling in the future.展开更多
文摘For an n-variable logic function,the power dissipation and area of the REED-MULLER （RM） circuit corresponding to each polarity are different. Based on the propagation algorithm of signal probability,the decomposition algorithm of a multi-input XOR/AND gate,and the multiple segment algorithm of polarity conversion,this paper successfully applies the whole annealing genetic algorithm （WAGA） to find the best polarity of an RM circuit. Through testing eight large-scale circuits from the Microelectronics Center North Carolina （MCNC） Benchmark, the SYNOPSYS synthesis results show that the RM circuits corresponding to the best polarity found using the proposed algorithm attain average power,area,and max delay savings of 77.2% ,62.4% ,and 9.2% respectively,compared with those under polarity 0.
基金Project 2007CB209400 supported by the National Basic Research Program of China
文摘Accuracy of time-depth conversion in data processing of transient electromagnetic prospecting always affects the accu- rate positioning of water bodies in coal mines. In order to improve the accuracy of time-depth conversion, we established a mathe- matical model of time-depth conversion for a transient electromagnetic method based on the theory of "double smoke ring effect" of full space transient electromagnetic field transmission. Using a 3-layer as well as a 4-layer geo-electric model for roadway floors, we performed the time-depth conversion of theoretical curves of apparent resistance varying over time. In these curves, the depth corresponding to extreme value points is nearly the same as the depth of a geo-electric model. The position of water body deter- mined by our time-depth conversion method agrees well with the result of borehole drilling, indicating that the established time-depth conversion model can clearly improve the accuracy of spatial positioning of water bodies in coal mines.
基金funded by the National Natural Science Foundation of China(42174131).
文摘Characterizing the petrophysical properties holds significant importance in shale oil reservoirs.Twodimensional(2-D)nuclear magnetic resonance(NMR),a nondestructive and noninvasive technique,has numerous applications in petrophysical characterization.However,the complex occurrence states of the fluids and the highly non-uniform distributions of minerals and organic matter pose challenges in the NMR-based petrophysical characterization.A novel T_(1)-T_(2)relaxation theory is introduced for the first time in this study.The transverse and longitudinal relaxivities of pore fluids are determined based on numerical investigation and experimental analysis.Additionally,an improved random walk algorithm is proposed to,on the basis of digital shale core,simulate the effects of the hydrogen index(HI)for the organic matter,echo spacing(T_(E)),pyrite content,clay mineral type,and clay content on T_(1)-T_(2)spectra at different NMR frequencies.Furthermore,the frequency conversion cross-plots for various petrophysical parameters influenced by the above factors are established.This study provides new insights into NMRbased petrophysical characterization and the frequency conversion of petrophysical parameters measured by laboratory NMR instruments and NMR logging in shale oil reservoirs.It is of great significance for the efficient exploration and environmentally friendly production of shale oil.
基金The National Twelfth Five Major Projects Subject--the deepwater area of northern South China Sea,rich hydrocarbon generation potential sag evaluation under contract No.2011ZX05025-002
文摘There are rich natural gas resources in the northwestern South China Sea deepwater areas, with poor degree of exploration. Because of the unique tectonic, sedimentary background of the region, velocity model building and time-depth conversion have been an important and difficult problem for a long time. Recent researches in this direction have revealed three major problems for deepwater areas, i.e., the way to determine error correction for drilling velocity, the optimization of velocity modeling, and the understanding and analysis of velocity variations in the slope areas. The present contribution proposes technical solutions to the problems：（1） velocity correction version can be established by analyzing the geology, reservoir, water depths and velocity spectrum characteristics;（2） a unified method can be adopted to analyze the velocity variation patterns in drilled pale structural positions;and （3） across-layer velocity is analyzed to establish the velocity model individually for each of the layers. Such a solution is applicable, as shown in an example from the northwestern South China Sea deepwater areas, in which an improved prediction precision is obtained.
文摘This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.
基金Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project number (IF2-PSAU/2022/01/22797).
文摘The generation of electricity,considering environmental and eco-nomic factors is one of the most important challenges of recent years.In this article,a thermoelectric generator(TEG)is proposed to use the thermal energy of an electric water heater(EWH)to generate electricity independently.To improve the energy conversion efficiency of the TEG,a fuzzy logic con-troller(FLC)-based perturb&observe(P&O)type maximum power point tracking(MPPT)control algorithm is used in this study.An EWH is one of the major electricity consuming household appliances which causes a higher electricity price for consumers.Also,a significant amount of thermal energy generated by EWH is wasted every day,especially during the winter season.In recent years,TEGs have been widely developed to convert surplus or unused thermal energy into usable electricity.In this context,the proposed model is designed to use the thermal energy stored in the EWH to generate electricity.In addition,the generated electricity can be easily stored in a battery storage system to supply electricity to various household appliances with low-power-consumption.The proposed MPPT control algorithm helps the system to quickly reach the optimal point corresponding to the maximum power output and maintains the system operating point at the maximum power output level.To validate the usefulness of the proposed scheme,a study model was developed in the MATLAB Simulink environment and its performance was investigated by simulation under steady state and transient conditions.The results of the study confirmed that the system is capable of generating adequate power from the available thermal energy of EWH.It was also found that the output power and efficiency of the system can be improved by maintaining a higher temperature difference at the input terminals of the TEG.Moreover,the real-time temperature data of Abha city in Saudi Arabia is considered to analyze the feasibility of the proposed system for practical implementation.
基金supported by the National Natural Science Foundation of China(61201301)Program of Zhejiang Provincial Education Department(Y201016542)
文摘A voice conversion algorithm,which makes use of the information between continuous frames of speech by compressed sensing,is proposed in this paper.According to the sparsity property of the concatenated vector of several continuous Linear Spectrum Pairs（LSP）in the discrete cosine transformation domain,this paper utilizes compressed sensing to extract the compressed vector from the concatenated LSPs and uses it as the feature vector to train the conversion function.The results of evaluations demonstrate that the performance of this approach can averagely improve 3.21%with the conventional algorithm based on weighted frequency warping when choosing the appropriate numbers of speech frame.The experimental results also illustrate that the performance of voice conversion system can be improved by taking full advantage of the inter-frame information,because those information can make the converted speech remain the more stable acoustic properties which is inherent in inter-frames.
基金Project supported by the National Natural Science Foundation of China(Nos.61076032,61234002)the Natural Science Foundation of Zhejiang Province(Nos.Z1111219,LY12D06002,LY13F040003)K.C.Wong Magna Fund in Ningbo University
文摘Conversion of the Reed–Muller（RM） expansion between two different polarities is an important step in the synthesis and optimization of RM circuits. By investigating XOR decomposition, a new conversion algorithm is proposed to convert MPRM expansion from one polarity to another. First, the relationship between XOR decomposition and mixed polarity is set up. Second, based on this, the operation relation of term coefficients between the two polarities is derived to realize MPRM expansion conversion. And finally, with the MCNC Benchmark, the resultsofouralgorithmshowthatitismoresuitablefordealingwithMPRMexpansionwithmoreterms.Compared to the previous tabular technique, the conversion efficiency is improved up to approximately 44.39%.
文摘为探究高比例可再生能源系统下风光资源的消纳与多元化利用途径,提出一种电氨转换及风光时空相关性的多能耦合系统两阶段鲁棒优化模型。首先分析了电制氨的运行机制,并结合直接氨燃料电池技术,探讨了电制氨与氨燃料电池协同运行的系统特性。为综合考虑风光出力的相关性与不确定性并选择最相近极限场景,该文采用最小体积封闭椭球算法构建高维椭球集,并通过1-范数和∞-范数建立风光出力场景的概率分布置信集,有效整合风光出力不确定性的分布信息。针对鲁棒优化模型中二元变量导致计算时间较长问题,该文提出了一种改进列与约束生成(column and constraint generation,C&CG)算法,利用三分块-交替方向乘子法和近似凸化方法分别处理主-子问题,并通过非精确C&CG算法对主-子问题进行迭代求解,在确保计算效率的同时,快速逼近最优解。结果表明,所提模型获取的极限场景能够准确捕捉风光出力的时空相关性及不确定性,电-氨转换系统有效促进了可再生能源的合理消纳,在确保系统安全稳定运行的同时,显著提升了调度经济性及求解效率。
基金supported by the National Natural Science Foundation of China(No.U22B2072)the Research Project of China Petroleum Science and Technology Innovation Fund(No.2025DQ02-0144).
文摘As the well drilling depth has broken through the 10,000 m in China,accurate measurements of downhole engineering parameters,such as annulus temperature and pressure for the whole wellbore,are significant in controlling potential downhole complexities.In this present work,a new micro-measurer is developed by integrating measurements of downhole temperature,pressure,magnetic field strength,and its own dynamic signals.The micro-measurer can flow with drilling fluid from the drillstring to the bottomhole and then float up back to the ground via the wellbore annulus.Compared with other downhole measurement tools that are fixedly connected to the drill string,its“measure-and-move-on”approach reduces the residence time in the high-temperature and high-pressure zone at the bottomhole;moreover,both the pressure and temperature at different well depth can be measured,thereby the temperature and pressure profiles of the whole wellbore can be constructed.In addition,the bluetooth low energy(BLE)technique is applied to offer the micro-measurer with the capability of wireless information transmission;while hydrodynamic optimization of the micro-measurer is carried out to design the structure of the micro-measurer,which can promote its recovery rate from downhole.In addition,an intelligent joint for releasing micro-measurers from the wellbore annulus is also proposed,aiming to overcome the limitation imposed by the nozzle on the size of the micro-measurer.Both the indoor experiments and the field tests have verified the feasibility of the newly designed micro-measurer,which is a key step for establishing a complete downhole internet of things(IoT)system to serve the intelligent drilling in the future.
