- 池保勇,石秉学
<正> The paper describes a novel low-power CMOS voltage-controlled oscillator (VCO) with dual-band local oscillating (LO) signal outputs for 5/2. 5-GHz wireless local area network (WLAN) transceivers. The VCO is based on an on-chip symmetrical spiral inductor and a differential varactor. The 2. 5-GHz quadrature LO signals are generated using the injection-locked frequency divider (ILFD) technique. The ILFD structure is similar to the VCO structure with its wide tracking range. The design tool ASITIC was used to optimize all on-chip symmetrical inductors. The power consumption was kept low with differential LC tanks and the ILFD technique. The circuit was implemented in a 0.18-fim CMOS process. Hspice and SpectreRF simulations show the proposed circuit could generate low phase noise 5/2. 5-GHz dual band LO signals with a wide tuning range. The 2. 5-GHz LO signals are quadrature with almost no phase and amplitude errors. The circuit consumes less than 5. 3mW in the tuning range with a power supply voltage of 1
2003年02期 121-125页 [查看摘要][在线阅读][下载 234k] [下载次数：92 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 池保勇,石秉学
<正> The paper describes a novel low-power CMOS voltage-controlled oscillator (VCO) with dual-band local oscillating (LO) signal outputs for 5/2. 5-GHz wireless local area network (WLAN) transceivers. The VCO is based on an on-chip symmetrical spiral inductor and a differential varactor. The 2. 5-GHz quadrature LO signals are generated using the injection-locked frequency divider (ILFD) technique. The ILFD structure is similar to the VCO structure with its wide tracking range. The design tool ASITIC was used to optimize all on-chip symmetrical inductors. The power consumption was kept low with differential LC tanks and the ILFD technique. The circuit was implemented in a 0.18-fim CMOS process. Hspice and SpectreRF simulations show the proposed circuit could generate low phase noise 5/2. 5-GHz dual band LO signals with a wide tuning range. The 2. 5-GHz LO signals are quadrature with almost no phase and amplitude errors. The circuit consumes less than 5. 3mW in the tuning range with a power supply voltage of 1
2003年02期 121-125页 [查看摘要][在线阅读][下载 234k] [下载次数：92 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 池保勇,石秉学
<正> The paper describes a novel low-power CMOS voltage-controlled oscillator (VCO) with dual-band local oscillating (LO) signal outputs for 5/2. 5-GHz wireless local area network (WLAN) transceivers. The VCO is based on an on-chip symmetrical spiral inductor and a differential varactor. The 2. 5-GHz quadrature LO signals are generated using the injection-locked frequency divider (ILFD) technique. The ILFD structure is similar to the VCO structure with its wide tracking range. The design tool ASITIC was used to optimize all on-chip symmetrical inductors. The power consumption was kept low with differential LC tanks and the ILFD technique. The circuit was implemented in a 0.18-fim CMOS process. Hspice and SpectreRF simulations show the proposed circuit could generate low phase noise 5/2. 5-GHz dual band LO signals with a wide tuning range. The 2. 5-GHz LO signals are quadrature with almost no phase and amplitude errors. The circuit consumes less than 5. 3mW in the tuning range with a power supply voltage of 1
2003年02期 121-125页 [查看摘要][在线阅读][下载 234k] [下载次数：92 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] <正> Jiang Kaili,a doctorate student of Tsinghua University,and his Colleagues have recently 1anded a majorprogress on developing carbon nanometer tube components by successfully pulling out carbon nanometertube threads from carbon nanometer tubes.The finding was published in Nature on October 24,2002.
2003年02期 125页 [查看摘要][在线阅读][下载 48k] [下载次数：16 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] -
<正> Jiang Kaili,a doctorate student of Tsinghua University,and his Colleagues have recently 1anded a majorprogress on developing carbon nanometer tube components by successfully pulling out carbon nanometertube threads from carbon nanometer tubes.The finding was published in Nature on October 24,2002.
2003年02期 125页 [查看摘要][在线阅读][下载 48k] [下载次数：16 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] <正> Jiang Kaili,a doctorate student of Tsinghua University,and his Colleagues have recently 1anded a majorprogress on developing carbon nanometer tube components by successfully pulling out carbon nanometertube threads from carbon nanometer tubes.The finding was published in Nature on October 24,2002.
2003年02期 125页 [查看摘要][在线阅读][下载 48k] [下载次数：16 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 赵宏锦,任天令,丛鹏,刘建设,刘理天,李志坚
<正> The most common typical bulk acoustic wave (BAW) filters are fabricated using bulk micromachining technology, but they have several disadvantages. This paper describes a new structure for front end passband BAW filters manufactured using surface micromachining. Porous silicon is used as a thick sacrificial layer. The structure reduces the influence of the support film on the filter to improve the VLSI compatibility as well as the filter quality. The cross-talk between resonators with different frequencies can be dramatically reduced by using resonators with a self-supporting structure.
2003年02期 126-129页 [查看摘要][在线阅读][下载 338k] [下载次数：58 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 赵宏锦,任天令,丛鹏,刘建设,刘理天,李志坚
<正> The most common typical bulk acoustic wave (BAW) filters are fabricated using bulk micromachining technology, but they have several disadvantages. This paper describes a new structure for front end passband BAW filters manufactured using surface micromachining. Porous silicon is used as a thick sacrificial layer. The structure reduces the influence of the support film on the filter to improve the VLSI compatibility as well as the filter quality. The cross-talk between resonators with different frequencies can be dramatically reduced by using resonators with a self-supporting structure.
2003年02期 126-129页 [查看摘要][在线阅读][下载 338k] [下载次数：58 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 赵宏锦,任天令,丛鹏,刘建设,刘理天,李志坚
<正> The most common typical bulk acoustic wave (BAW) filters are fabricated using bulk micromachining technology, but they have several disadvantages. This paper describes a new structure for front end passband BAW filters manufactured using surface micromachining. Porous silicon is used as a thick sacrificial layer. The structure reduces the influence of the support film on the filter to improve the VLSI compatibility as well as the filter quality. The cross-talk between resonators with different frequencies can be dramatically reduced by using resonators with a self-supporting structure.
2003年02期 126-129页 [查看摘要][在线阅读][下载 338k] [下载次数：58 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 黄文韬,罗广礼,史进,邓宁,陈培毅,钱佩信
<正> High-vacuum/chemical-vapor deposition (HV/CVD) system was used to grow relaxed SiGe buffer layers on Si substrates. Several methods were then used to analyze the quality of the SiGe films. X-ray diffraction and Raman spectroscopy showed that the upper layer was almost fully relaxed. Second ion mass spectroscopy showed that the Ge compositions were step-graded. Transmission electron microscopy showed that the misfit dislocations were restrained to the graded SiGe layers. Tests of the electrical properties of tensile-strained Si on relaxed SiGe buffer layers showed that their transconductances were higher than that of Si devices. These results verify the high quality of the relaxed SiGe buffer layer. The calculated critical layer thicknesses of the graded Si1-xGex layer on Si substrate and a Si layer on the relaxed SiGe buffer layer agree well with experimental results.
2003年02期 130-134页 [查看摘要][在线阅读][下载 411k] [下载次数：30 ] |[网刊下载次数：0 ] |[引用频次：3 ] |[阅读次数：0 ] - 黄文韬,罗广礼,史进,邓宁,陈培毅,钱佩信
<正> High-vacuum/chemical-vapor deposition (HV/CVD) system was used to grow relaxed SiGe buffer layers on Si substrates. Several methods were then used to analyze the quality of the SiGe films. X-ray diffraction and Raman spectroscopy showed that the upper layer was almost fully relaxed. Second ion mass spectroscopy showed that the Ge compositions were step-graded. Transmission electron microscopy showed that the misfit dislocations were restrained to the graded SiGe layers. Tests of the electrical properties of tensile-strained Si on relaxed SiGe buffer layers showed that their transconductances were higher than that of Si devices. These results verify the high quality of the relaxed SiGe buffer layer. The calculated critical layer thicknesses of the graded Si1-xGex layer on Si substrate and a Si layer on the relaxed SiGe buffer layer agree well with experimental results.
2003年02期 130-134页 [查看摘要][在线阅读][下载 411k] [下载次数：30 ] |[网刊下载次数：0 ] |[引用频次：3 ] |[阅读次数：0 ] - 黄文韬,罗广礼,史进,邓宁,陈培毅,钱佩信
<正> High-vacuum/chemical-vapor deposition (HV/CVD) system was used to grow relaxed SiGe buffer layers on Si substrates. Several methods were then used to analyze the quality of the SiGe films. X-ray diffraction and Raman spectroscopy showed that the upper layer was almost fully relaxed. Second ion mass spectroscopy showed that the Ge compositions were step-graded. Transmission electron microscopy showed that the misfit dislocations were restrained to the graded SiGe layers. Tests of the electrical properties of tensile-strained Si on relaxed SiGe buffer layers showed that their transconductances were higher than that of Si devices. These results verify the high quality of the relaxed SiGe buffer layer. The calculated critical layer thicknesses of the graded Si1-xGex layer on Si substrate and a Si layer on the relaxed SiGe buffer layer agree well with experimental results.
2003年02期 130-134页 [查看摘要][在线阅读][下载 411k] [下载次数：30 ] |[网刊下载次数：0 ] |[引用频次：3 ] |[阅读次数：0 ] - 任天令,赵宏锦,丛鹏,刘燕翔,刘建设,刘理天,李志坚
<正> Analytical solutions are presented for the wave equation for the electrode-piezoelectric-electrode sandwich structure in film bulk acoustic resonators (FBAR). The impedance for lead-zirconate-titanate (PZT)-based FBAR was derived using the proper boundary conditions and material parameters. A method is presented to adjust the resonant frequency based on the process and material properties. Ferroelectric-based radio-frequency filters were designed using FBARs. An accurate result is given for the filter impedance which can be used for other piezoelectric devices.
2003年02期 135-138页 [查看摘要][在线阅读][下载 237k] [下载次数：73 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 任天令,赵宏锦,丛鹏,刘燕翔,刘建设,刘理天,李志坚
<正> Analytical solutions are presented for the wave equation for the electrode-piezoelectric-electrode sandwich structure in film bulk acoustic resonators (FBAR). The impedance for lead-zirconate-titanate (PZT)-based FBAR was derived using the proper boundary conditions and material parameters. A method is presented to adjust the resonant frequency based on the process and material properties. Ferroelectric-based radio-frequency filters were designed using FBARs. An accurate result is given for the filter impedance which can be used for other piezoelectric devices.
2003年02期 135-138页 [查看摘要][在线阅读][下载 237k] [下载次数：73 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 任天令,赵宏锦,丛鹏,刘燕翔,刘建设,刘理天,李志坚
<正> Analytical solutions are presented for the wave equation for the electrode-piezoelectric-electrode sandwich structure in film bulk acoustic resonators (FBAR). The impedance for lead-zirconate-titanate (PZT)-based FBAR was derived using the proper boundary conditions and material parameters. A method is presented to adjust the resonant frequency based on the process and material properties. Ferroelectric-based radio-frequency filters were designed using FBARs. An accurate result is given for the filter impedance which can be used for other piezoelectric devices.
2003年02期 135-138页 [查看摘要][在线阅读][下载 237k] [下载次数：73 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 张志君,范玉顺
<正> Workflow process definition language (WPDL) facilitates the transfer of workflow process definitions between separate workflow products. However, much work is still needed to transfer the specific workflow model to a WPDL conforming model. CIMFlow is a workflow management system developed by the National CIMS Engineering Research Center. This paper discusses the methods by which the CIMFlow model conforms to the WPDL meta-model and the differences between the WPDL meta-model and the CIMFlow model. Some improvements are proposed for the WPDL specification. Finally, the mapping and translating methods between the entities and attributes are given for the two models. The proposed methods and improvements are valuable as a reference for other mapping applications and the WPDL specification.
2003年02期 139-144页 [查看摘要][在线阅读][下载 308k] [下载次数：49 ] |[网刊下载次数：0 ] |[引用频次：10 ] |[阅读次数：0 ] - 张志君,范玉顺
<正> Workflow process definition language (WPDL) facilitates the transfer of workflow process definitions between separate workflow products. However, much work is still needed to transfer the specific workflow model to a WPDL conforming model. CIMFlow is a workflow management system developed by the National CIMS Engineering Research Center. This paper discusses the methods by which the CIMFlow model conforms to the WPDL meta-model and the differences between the WPDL meta-model and the CIMFlow model. Some improvements are proposed for the WPDL specification. Finally, the mapping and translating methods between the entities and attributes are given for the two models. The proposed methods and improvements are valuable as a reference for other mapping applications and the WPDL specification.
2003年02期 139-144页 [查看摘要][在线阅读][下载 308k] [下载次数：49 ] |[网刊下载次数：0 ] |[引用频次：10 ] |[阅读次数：0 ] - 张志君,范玉顺
<正> Workflow process definition language (WPDL) facilitates the transfer of workflow process definitions between separate workflow products. However, much work is still needed to transfer the specific workflow model to a WPDL conforming model. CIMFlow is a workflow management system developed by the National CIMS Engineering Research Center. This paper discusses the methods by which the CIMFlow model conforms to the WPDL meta-model and the differences between the WPDL meta-model and the CIMFlow model. Some improvements are proposed for the WPDL specification. Finally, the mapping and translating methods between the entities and attributes are given for the two models. The proposed methods and improvements are valuable as a reference for other mapping applications and the WPDL specification.
2003年02期 139-144页 [查看摘要][在线阅读][下载 308k] [下载次数：49 ] |[网刊下载次数：0 ] |[引用频次：10 ] |[阅读次数：0 ] - 罗平,周爱辉
<正> Multi-parameter asymptotic expansions are interesting since they justify the use of multi-parameter extrapolation which can be implemented in parallel and are well studied in many papers for the conforming finite element methods. For the nonconforming finite element methods, however, the work of the multi-parameter asymptotic expansions and extrapolation have seldom been found in the literature. This paper considers the solution of the biharmonic equation using Adini nonconforming finite elements and reports new results for the multi-parameter asymptotic expansions and extrapolation. The Adini nonconforming finite element solution of the biharmonic equation is shown to have a multi-parameter asymptotic error expansion and extrapolation. This expansion and a multi-parameter extrapolation technique were used to develop an accurate approximation parallel algorithm for the biharmonic equation. Finally, numerical results have verified the extrapolation theory.
2003年02期 145-150页 [查看摘要][在线阅读][下载 276k] [下载次数：24 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 罗平,周爱辉
<正> Multi-parameter asymptotic expansions are interesting since they justify the use of multi-parameter extrapolation which can be implemented in parallel and are well studied in many papers for the conforming finite element methods. For the nonconforming finite element methods, however, the work of the multi-parameter asymptotic expansions and extrapolation have seldom been found in the literature. This paper considers the solution of the biharmonic equation using Adini nonconforming finite elements and reports new results for the multi-parameter asymptotic expansions and extrapolation. The Adini nonconforming finite element solution of the biharmonic equation is shown to have a multi-parameter asymptotic error expansion and extrapolation. This expansion and a multi-parameter extrapolation technique were used to develop an accurate approximation parallel algorithm for the biharmonic equation. Finally, numerical results have verified the extrapolation theory.
2003年02期 145-150页 [查看摘要][在线阅读][下载 276k] [下载次数：24 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 罗平,周爱辉
<正> Multi-parameter asymptotic expansions are interesting since they justify the use of multi-parameter extrapolation which can be implemented in parallel and are well studied in many papers for the conforming finite element methods. For the nonconforming finite element methods, however, the work of the multi-parameter asymptotic expansions and extrapolation have seldom been found in the literature. This paper considers the solution of the biharmonic equation using Adini nonconforming finite elements and reports new results for the multi-parameter asymptotic expansions and extrapolation. The Adini nonconforming finite element solution of the biharmonic equation is shown to have a multi-parameter asymptotic error expansion and extrapolation. This expansion and a multi-parameter extrapolation technique were used to develop an accurate approximation parallel algorithm for the biharmonic equation. Finally, numerical results have verified the extrapolation theory.
2003年02期 145-150页 [查看摘要][在线阅读][下载 276k] [下载次数：24 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 王浩,沈国斌,李世鹏,钟玉琢
<正> Research on application-level multicast seeks to combine the merits of unicast and IP multicast while avoiding their drawbacks. Efficient error recovery in such a system is still a difficult problem. Current research is primarily focused on developing local error recovery techniques, but these techniques would not work with shared losses, which often occur in application-level multicast. This paper presents a novel multimedia streaming framework called peer-paired pyramid streaming (P3S) which is basically a hybrid client/server and peer-to-peer structure. In P3S, clients are hierarchically organized with those at the same level coupled as peer pairs. P3S uses some controlled delay between packets that are vulnerable to shared losses to reduce the shared losses. The technique is verified by both theoretical and experimental results.
2003年02期 151-155页 [查看摘要][在线阅读][下载 366k] [下载次数：25 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 王浩,沈国斌,李世鹏,钟玉琢
<正> Research on application-level multicast seeks to combine the merits of unicast and IP multicast while avoiding their drawbacks. Efficient error recovery in such a system is still a difficult problem. Current research is primarily focused on developing local error recovery techniques, but these techniques would not work with shared losses, which often occur in application-level multicast. This paper presents a novel multimedia streaming framework called peer-paired pyramid streaming (P3S) which is basically a hybrid client/server and peer-to-peer structure. In P3S, clients are hierarchically organized with those at the same level coupled as peer pairs. P3S uses some controlled delay between packets that are vulnerable to shared losses to reduce the shared losses. The technique is verified by both theoretical and experimental results.
2003年02期 151-155页 [查看摘要][在线阅读][下载 366k] [下载次数：25 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 王浩,沈国斌,李世鹏,钟玉琢
<正> Research on application-level multicast seeks to combine the merits of unicast and IP multicast while avoiding their drawbacks. Efficient error recovery in such a system is still a difficult problem. Current research is primarily focused on developing local error recovery techniques, but these techniques would not work with shared losses, which often occur in application-level multicast. This paper presents a novel multimedia streaming framework called peer-paired pyramid streaming (P3S) which is basically a hybrid client/server and peer-to-peer structure. In P3S, clients are hierarchically organized with those at the same level coupled as peer pairs. P3S uses some controlled delay between packets that are vulnerable to shared losses to reduce the shared losses. The technique is verified by both theoretical and experimental results.
2003年02期 151-155页 [查看摘要][在线阅读][下载 366k] [下载次数：25 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 陈俊燕,李涓子,王作英
<正> A novel word graph expansion algorithm for voice command understanding is presented as the basis of a more accurate and robust voice command system. Tests show that the algorithm has much better performance than the generally-adopted N-best algorithm while maintaining high computational efficiency. Also the error tolerance method used to improve the robustness of the voice command understanding module further decreases the understanding error rate (UER) to 16. 6% with the computational efficiency almost unchanged compared to the case without error tolerance.
2003年02期 156-160页 [查看摘要][在线阅读][下载 280k] [下载次数：33 ] |[网刊下载次数：0 ] |[引用频次：7 ] |[阅读次数：0 ] - 陈俊燕,李涓子,王作英
<正> A novel word graph expansion algorithm for voice command understanding is presented as the basis of a more accurate and robust voice command system. Tests show that the algorithm has much better performance than the generally-adopted N-best algorithm while maintaining high computational efficiency. Also the error tolerance method used to improve the robustness of the voice command understanding module further decreases the understanding error rate (UER) to 16. 6% with the computational efficiency almost unchanged compared to the case without error tolerance.
2003年02期 156-160页 [查看摘要][在线阅读][下载 280k] [下载次数：33 ] |[网刊下载次数：0 ] |[引用频次：7 ] |[阅读次数：0 ] - 陈俊燕,李涓子,王作英
<正> A novel word graph expansion algorithm for voice command understanding is presented as the basis of a more accurate and robust voice command system. Tests show that the algorithm has much better performance than the generally-adopted N-best algorithm while maintaining high computational efficiency. Also the error tolerance method used to improve the robustness of the voice command understanding module further decreases the understanding error rate (UER) to 16. 6% with the computational efficiency almost unchanged compared to the case without error tolerance.
2003年02期 156-160页 [查看摘要][在线阅读][下载 280k] [下载次数：33 ] |[网刊下载次数：0 ] |[引用频次：7 ] |[阅读次数：0 ] - 张理洪,谢长生,裴先登,Ulrich Kleine
<正> This paper presents a novel genetic algorithm for analog module placement based on a generalization of the two-dimensional bin packing problem. The genetic encoding and operators assure that all problem constraints are always satisfied. Thus the potential problems of adding penalty terms to the cost function are eliminated so that the search configuration space is drastically decreased. The dedicated cost function is based on the special requirements of analog integrated circuits. A fractional factorial experiment was conducted using an orthogonal array to study the algorithm parameters. A meta-GA was applied to determine the optimal parameter values. The algorithm was tested with several local benchmark circuits. The experimental results show that the algorithm has better performance than the simulated annealing approach with satisfactory results comparable to manual placement. This study demonstrates the effectiveness of the genetic algorithm in the analog module placement problem. The algorithm has b
2003年02期 161-168页 [查看摘要][在线阅读][下载 576k] [下载次数：24 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 张理洪,谢长生,裴先登,Ulrich Kleine
<正> This paper presents a novel genetic algorithm for analog module placement based on a generalization of the two-dimensional bin packing problem. The genetic encoding and operators assure that all problem constraints are always satisfied. Thus the potential problems of adding penalty terms to the cost function are eliminated so that the search configuration space is drastically decreased. The dedicated cost function is based on the special requirements of analog integrated circuits. A fractional factorial experiment was conducted using an orthogonal array to study the algorithm parameters. A meta-GA was applied to determine the optimal parameter values. The algorithm was tested with several local benchmark circuits. The experimental results show that the algorithm has better performance than the simulated annealing approach with satisfactory results comparable to manual placement. This study demonstrates the effectiveness of the genetic algorithm in the analog module placement problem. The algorithm has b
2003年02期 161-168页 [查看摘要][在线阅读][下载 576k] [下载次数：24 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 张理洪,谢长生,裴先登,Ulrich Kleine
<正> This paper presents a novel genetic algorithm for analog module placement based on a generalization of the two-dimensional bin packing problem. The genetic encoding and operators assure that all problem constraints are always satisfied. Thus the potential problems of adding penalty terms to the cost function are eliminated so that the search configuration space is drastically decreased. The dedicated cost function is based on the special requirements of analog integrated circuits. A fractional factorial experiment was conducted using an orthogonal array to study the algorithm parameters. A meta-GA was applied to determine the optimal parameter values. The algorithm was tested with several local benchmark circuits. The experimental results show that the algorithm has better performance than the simulated annealing approach with satisfactory results comparable to manual placement. This study demonstrates the effectiveness of the genetic algorithm in the analog module placement problem. The algorithm has b
2003年02期 161-168页 [查看摘要][在线阅读][下载 576k] [下载次数：24 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 马赓宇,林学訚
<正> Gesture analysis by computer is an important part of the human computer interface (HCI) and a gesture analysis method was developed using a skin-color-based method to extract the area representing the hand in a single image with a distribution feature measurement designed to describe the hand shape in the images. A hidden Markov model (HMM) based method was used to analyze the temporal variation and segmentation of continuous operational gestures. Furthermore, a transition HMM was used to represent the period between gestures, so the method could segment continuous gestures and eliminate non-standard gestures. The system can analyze 2 frames per second, which is sufficient for real time analysis.
2003年02期 169-173页 [查看摘要][在线阅读][下载 648k] [下载次数：42 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 马赓宇,林学訚
<正> Gesture analysis by computer is an important part of the human computer interface (HCI) and a gesture analysis method was developed using a skin-color-based method to extract the area representing the hand in a single image with a distribution feature measurement designed to describe the hand shape in the images. A hidden Markov model (HMM) based method was used to analyze the temporal variation and segmentation of continuous operational gestures. Furthermore, a transition HMM was used to represent the period between gestures, so the method could segment continuous gestures and eliminate non-standard gestures. The system can analyze 2 frames per second, which is sufficient for real time analysis.
2003年02期 169-173页 [查看摘要][在线阅读][下载 648k] [下载次数：42 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 马赓宇,林学訚
<正> Gesture analysis by computer is an important part of the human computer interface (HCI) and a gesture analysis method was developed using a skin-color-based method to extract the area representing the hand in a single image with a distribution feature measurement designed to describe the hand shape in the images. A hidden Markov model (HMM) based method was used to analyze the temporal variation and segmentation of continuous operational gestures. Furthermore, a transition HMM was used to represent the period between gestures, so the method could segment continuous gestures and eliminate non-standard gestures. The system can analyze 2 frames per second, which is sufficient for real time analysis.
2003年02期 169-173页 [查看摘要][在线阅读][下载 648k] [下载次数：42 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 靳晓明,王丽坤,陆玉昌,石纯一
<正> Index structure that enables efficient similarity queries in high-dimensional space is crucial for many applications. This paper discusses the indexing problem in dataset composed of partially clustered data, which exists in many applications. Current index methods are inefficient with partially clustered datasets. The dynamic and adaptive index structure presented here, called a multi-cluster tree (MC-tree), consists of a set of height-balanced trees for indexing. This index structure improves the querying efficiency in three ways: 1) Most bounding regions achieve uniform distributions, which results in fewer splits and less overlap compared with a single indexing tree. 2) The clusters in the dataset are dynamically detected when the index is updated. 3) The query process does not involve a sequential scan. The MC-tree was shown to be better than hierarchical and cluster-based indexes for the partially clustered datasets.
2003年02期 174-180页 [查看摘要][在线阅读][下载 390k] [下载次数：36 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 靳晓明,王丽坤,陆玉昌,石纯一
<正> Index structure that enables efficient similarity queries in high-dimensional space is crucial for many applications. This paper discusses the indexing problem in dataset composed of partially clustered data, which exists in many applications. Current index methods are inefficient with partially clustered datasets. The dynamic and adaptive index structure presented here, called a multi-cluster tree (MC-tree), consists of a set of height-balanced trees for indexing. This index structure improves the querying efficiency in three ways: 1) Most bounding regions achieve uniform distributions, which results in fewer splits and less overlap compared with a single indexing tree. 2) The clusters in the dataset are dynamically detected when the index is updated. 3) The query process does not involve a sequential scan. The MC-tree was shown to be better than hierarchical and cluster-based indexes for the partially clustered datasets.
2003年02期 174-180页 [查看摘要][在线阅读][下载 390k] [下载次数：36 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 靳晓明,王丽坤,陆玉昌,石纯一
<正> Index structure that enables efficient similarity queries in high-dimensional space is crucial for many applications. This paper discusses the indexing problem in dataset composed of partially clustered data, which exists in many applications. Current index methods are inefficient with partially clustered datasets. The dynamic and adaptive index structure presented here, called a multi-cluster tree (MC-tree), consists of a set of height-balanced trees for indexing. This index structure improves the querying efficiency in three ways: 1) Most bounding regions achieve uniform distributions, which results in fewer splits and less overlap compared with a single indexing tree. 2) The clusters in the dataset are dynamically detected when the index is updated. 3) The query process does not involve a sequential scan. The MC-tree was shown to be better than hierarchical and cluster-based indexes for the partially clustered datasets.
2003年02期 174-180页 [查看摘要][在线阅读][下载 390k] [下载次数：36 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 陈德刚,张文修,宋士吉
<正> This paper generalizes the Pawlak rough set method to a completely distributive lattice. The concept of a rough set has many applications in data mining. The approximation operators on a completely distributive lattice are studied, the rough class on a completely distributive lattice is defined and the expressional theorems of the rough class are proven. These expressional theorems are used to prove that the collection of all rough classes is an atomic completely distributive lattice.
2003年02期 181-184页 [查看摘要][在线阅读][下载 200k] [下载次数：56 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 陈德刚,张文修,宋士吉
<正> This paper generalizes the Pawlak rough set method to a completely distributive lattice. The concept of a rough set has many applications in data mining. The approximation operators on a completely distributive lattice are studied, the rough class on a completely distributive lattice is defined and the expressional theorems of the rough class are proven. These expressional theorems are used to prove that the collection of all rough classes is an atomic completely distributive lattice.
2003年02期 181-184页 [查看摘要][在线阅读][下载 200k] [下载次数：56 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 陈德刚,张文修,宋士吉
<正> This paper generalizes the Pawlak rough set method to a completely distributive lattice. The concept of a rough set has many applications in data mining. The approximation operators on a completely distributive lattice are studied, the rough class on a completely distributive lattice is defined and the expressional theorems of the rough class are proven. These expressional theorems are used to prove that the collection of all rough classes is an atomic completely distributive lattice.
2003年02期 181-184页 [查看摘要][在线阅读][下载 200k] [下载次数：56 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 孔红伟,葛宁,阮方,冯重熙
<正> A congestion control algorithm is proposed for resilient packet ring (RPR) in this paper. In this algorithm, nonlinear explicit rate feedback control is used to ensure fast convergence and smooth equilibrium behavior. The algorithm combines explicit rate control with a deficit round robin (DRR) scheduler, which not only ensures fairness, but also avoids the implementation difficulties of explicit rate control algorithms. The algorithm has good features of fairness, fast convergence, smooth equilibrium, low queue depth, and easy implementation. It is insensitive to the loss of congestion control packets and can adapt to a wide range of link rates and network scales. It has solved the unbalanced traffic problem of spatial reuse protocol (SRP). The algorithm can be implemented on the multi-access control layer of RPR nodes to ensure fair and efficient access of the best-effort traffic.
2003年02期 185-191页 [查看摘要][在线阅读][下载 411k] [下载次数：33 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 孔红伟,葛宁,阮方,冯重熙
<正> A congestion control algorithm is proposed for resilient packet ring (RPR) in this paper. In this algorithm, nonlinear explicit rate feedback control is used to ensure fast convergence and smooth equilibrium behavior. The algorithm combines explicit rate control with a deficit round robin (DRR) scheduler, which not only ensures fairness, but also avoids the implementation difficulties of explicit rate control algorithms. The algorithm has good features of fairness, fast convergence, smooth equilibrium, low queue depth, and easy implementation. It is insensitive to the loss of congestion control packets and can adapt to a wide range of link rates and network scales. It has solved the unbalanced traffic problem of spatial reuse protocol (SRP). The algorithm can be implemented on the multi-access control layer of RPR nodes to ensure fair and efficient access of the best-effort traffic.
2003年02期 185-191页 [查看摘要][在线阅读][下载 411k] [下载次数：33 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 孔红伟,葛宁,阮方,冯重熙
<正> A congestion control algorithm is proposed for resilient packet ring (RPR) in this paper. In this algorithm, nonlinear explicit rate feedback control is used to ensure fast convergence and smooth equilibrium behavior. The algorithm combines explicit rate control with a deficit round robin (DRR) scheduler, which not only ensures fairness, but also avoids the implementation difficulties of explicit rate control algorithms. The algorithm has good features of fairness, fast convergence, smooth equilibrium, low queue depth, and easy implementation. It is insensitive to the loss of congestion control packets and can adapt to a wide range of link rates and network scales. It has solved the unbalanced traffic problem of spatial reuse protocol (SRP). The algorithm can be implemented on the multi-access control layer of RPR nodes to ensure fair and efficient access of the best-effort traffic.
2003年02期 185-191页 [查看摘要][在线阅读][下载 411k] [下载次数：33 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] -
<正> The 2001 Science and Technology Rewarded Meeting was held in the Main Building recently. In the meeting, Gong Ke,the vice president of Tsinghua,reviewed the scientific research in 2001.Wen Shizhu, academician of the PrecisionInstruments Department,Wu Zongxin,professor of the Nuclear Energy Research Institute, Liu Guanzhong, professor of
2003年02期 191页 [查看摘要][在线阅读][下载 66k] [下载次数：9 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] <正> The 2001 Science and Technology Rewarded Meeting was held in the Main Building recently. In the meeting, Gong Ke,the vice president of Tsinghua,reviewed the scientific research in 2001.Wen Shizhu, academician of the PrecisionInstruments Department,Wu Zongxin,professor of the Nuclear Energy Research Institute, Liu Guanzhong, professor of
2003年02期 191页 [查看摘要][在线阅读][下载 66k] [下载次数：9 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] -
<正> The 2001 Science and Technology Rewarded Meeting was held in the Main Building recently. In the meeting, Gong Ke,the vice president of Tsinghua,reviewed the scientific research in 2001.Wen Shizhu, academician of the PrecisionInstruments Department,Wu Zongxin,professor of the Nuclear Energy Research Institute, Liu Guanzhong, professor of
2003年02期 191页 [查看摘要][在线阅读][下载 66k] [下载次数：9 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 周杰韩,熊光楞,张和明,曾庆良
<正> Networked agile manufacturing (NAM) is a new manufacturing paradigm for the 21st century. Manufacturing businesses based on NAM are characterized by virtual organization, innovation, global sourcing of materials and production centered on the workforce. Therefore, NAM requires a knowledgeable, motivated workforce. This paper reviews the literature related to developing an NAM curriculum to: (1) review the progress for organizing manufacturing information, (2) study the fundamental technologies impacting NAM, including product data management (RDM), enterprise resource planning (ERP), and component/supplier management (CSM), (3) present a definition of NAM and its conceptual framework, and (4) generalize the basic NAM curriculum. The NAM curriculum can be used for developing a manufacturing course.
2003年02期 192-197页 [查看摘要][在线阅读][下载 306k] [下载次数：87 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 周杰韩,熊光楞,张和明,曾庆良
<正> Networked agile manufacturing (NAM) is a new manufacturing paradigm for the 21st century. Manufacturing businesses based on NAM are characterized by virtual organization, innovation, global sourcing of materials and production centered on the workforce. Therefore, NAM requires a knowledgeable, motivated workforce. This paper reviews the literature related to developing an NAM curriculum to: (1) review the progress for organizing manufacturing information, (2) study the fundamental technologies impacting NAM, including product data management (RDM), enterprise resource planning (ERP), and component/supplier management (CSM), (3) present a definition of NAM and its conceptual framework, and (4) generalize the basic NAM curriculum. The NAM curriculum can be used for developing a manufacturing course.
2003年02期 192-197页 [查看摘要][在线阅读][下载 306k] [下载次数：87 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 周杰韩,熊光楞,张和明,曾庆良
<正> Networked agile manufacturing (NAM) is a new manufacturing paradigm for the 21st century. Manufacturing businesses based on NAM are characterized by virtual organization, innovation, global sourcing of materials and production centered on the workforce. Therefore, NAM requires a knowledgeable, motivated workforce. This paper reviews the literature related to developing an NAM curriculum to: (1) review the progress for organizing manufacturing information, (2) study the fundamental technologies impacting NAM, including product data management (RDM), enterprise resource planning (ERP), and component/supplier management (CSM), (3) present a definition of NAM and its conceptual framework, and (4) generalize the basic NAM curriculum. The NAM curriculum can be used for developing a manufacturing course.
2003年02期 192-197页 [查看摘要][在线阅读][下载 306k] [下载次数：87 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 李子臣,成军祥,戴一奇
<正> Piveteau signature scheme allows message recovery but the methodology differs from that of the Nyberg-Rueppel schemes. This paper analyzes the security of the Piveteau scheme by designing some attacks. Two improved methods to Piveteau signature scheme and Nyberg-Rueppel schemes were developed to avoid these weaknesses. Analyses of the security of the improved schemes prove that the improved methods can effectively handle the attacks proposed in this paper.
2003年02期 198-200页 [查看摘要][在线阅读][下载 172k] [下载次数：29 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 李子臣,成军祥,戴一奇
<正> Piveteau signature scheme allows message recovery but the methodology differs from that of the Nyberg-Rueppel schemes. This paper analyzes the security of the Piveteau scheme by designing some attacks. Two improved methods to Piveteau signature scheme and Nyberg-Rueppel schemes were developed to avoid these weaknesses. Analyses of the security of the improved schemes prove that the improved methods can effectively handle the attacks proposed in this paper.
2003年02期 198-200页 [查看摘要][在线阅读][下载 172k] [下载次数：29 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 李子臣,成军祥,戴一奇
<正> Piveteau signature scheme allows message recovery but the methodology differs from that of the Nyberg-Rueppel schemes. This paper analyzes the security of the Piveteau scheme by designing some attacks. Two improved methods to Piveteau signature scheme and Nyberg-Rueppel schemes were developed to avoid these weaknesses. Analyses of the security of the improved schemes prove that the improved methods can effectively handle the attacks proposed in this paper.
2003年02期 198-200页 [查看摘要][在线阅读][下载 172k] [下载次数：29 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 程进,江见鲸,肖汝诚,项海帆
<正> The increasing span of cable-stayed bridges has focused more attention on the aerostatic stability of the design and construction of such bridges. This paper presents a new method to analyze the nonlinear aerostatic stability of cable-stayed bridges including all three components of the wind load and the geometric nonlinearity. The analysis was used to investigate the effects of the wind angle of incidence, the wind load of individual bridge elements, the sagging of cable elements, the changes of tower height and the changes of side span length on the aerostatic stability of cable-stayed bridges. The results show that the wind angle of incidence and the wind loads on the cables have an important effect on the aerostatic stability of cable-stayed bridges.
2003年02期 201-205页 [查看摘要][在线阅读][下载 265k] [下载次数：148 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 程进,江见鲸,肖汝诚,项海帆
<正> The increasing span of cable-stayed bridges has focused more attention on the aerostatic stability of the design and construction of such bridges. This paper presents a new method to analyze the nonlinear aerostatic stability of cable-stayed bridges including all three components of the wind load and the geometric nonlinearity. The analysis was used to investigate the effects of the wind angle of incidence, the wind load of individual bridge elements, the sagging of cable elements, the changes of tower height and the changes of side span length on the aerostatic stability of cable-stayed bridges. The results show that the wind angle of incidence and the wind loads on the cables have an important effect on the aerostatic stability of cable-stayed bridges.
2003年02期 201-205页 [查看摘要][在线阅读][下载 265k] [下载次数：148 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 程进,江见鲸,肖汝诚,项海帆
<正> The increasing span of cable-stayed bridges has focused more attention on the aerostatic stability of the design and construction of such bridges. This paper presents a new method to analyze the nonlinear aerostatic stability of cable-stayed bridges including all three components of the wind load and the geometric nonlinearity. The analysis was used to investigate the effects of the wind angle of incidence, the wind load of individual bridge elements, the sagging of cable elements, the changes of tower height and the changes of side span length on the aerostatic stability of cable-stayed bridges. The results show that the wind angle of incidence and the wind loads on the cables have an important effect on the aerostatic stability of cable-stayed bridges.
2003年02期 201-205页 [查看摘要][在线阅读][下载 265k] [下载次数：148 ] |[网刊下载次数：0 ] |[引用频次：1 ] |[阅读次数：0 ] - 华永霞,钟宏志
<正> The recently proposed concept of the triangular differential quadrature method (TDQM) is applied to the bending analysis of Reissner plates with various curvilinear geometries subjected to various combinations of boundary conditions. A unit isosceles right triangle is used as the standard triangle for all the derivatives expressed using the triangular differential quadrature rule. Geometric transformations are introduced using basis functions to determine the weighting coefficients for the triangular differential quadrature to map an arbitrary curvilinear triangle into the standard triangle. The triangular differential quadrature method provides good accuracy and rapid convergence relative to other available exact and numerical results.
2003年02期 206-214页 [查看摘要][在线阅读][下载 419k] [下载次数：38 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 华永霞,钟宏志
<正> The recently proposed concept of the triangular differential quadrature method (TDQM) is applied to the bending analysis of Reissner plates with various curvilinear geometries subjected to various combinations of boundary conditions. A unit isosceles right triangle is used as the standard triangle for all the derivatives expressed using the triangular differential quadrature rule. Geometric transformations are introduced using basis functions to determine the weighting coefficients for the triangular differential quadrature to map an arbitrary curvilinear triangle into the standard triangle. The triangular differential quadrature method provides good accuracy and rapid convergence relative to other available exact and numerical results.
2003年02期 206-214页 [查看摘要][在线阅读][下载 419k] [下载次数：38 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 华永霞,钟宏志
<正> The recently proposed concept of the triangular differential quadrature method (TDQM) is applied to the bending analysis of Reissner plates with various curvilinear geometries subjected to various combinations of boundary conditions. A unit isosceles right triangle is used as the standard triangle for all the derivatives expressed using the triangular differential quadrature rule. Geometric transformations are introduced using basis functions to determine the weighting coefficients for the triangular differential quadrature to map an arbitrary curvilinear triangle into the standard triangle. The triangular differential quadrature method provides good accuracy and rapid convergence relative to other available exact and numerical results.
2003年02期 206-214页 [查看摘要][在线阅读][下载 419k] [下载次数：38 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 何伯述,刁永发,许晋源,陈昌和
<正> Vorticity, which represents the rotation of a fluid element, is an important characteristic of turbulence. Various methods have been used to measure vorticity. A hot-wire/hot-film anemometer (HWA) was used here to measure the vorticity in turbulent flows. The velocity components and their partial derivatives were simultaneously measured with a new 6-sensor hot-wire (HW) probe assuming ideal yaw and pitch factors with Jorgensen's expression and Taylor's hypothesis to analyze the data. The accurate 6-sensor hot-wire probe results for the velocity field were used to determine the velocity gradients and, therefore, the vorticity vector field. The data was measured in an isothermal model of a tangentially fired furnace. The experimental results in the tangentially fired furnace agree with numerical results.
2003年02期 215-223页 [查看摘要][在线阅读][下载 549k] [下载次数：50 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 何伯述,刁永发,许晋源,陈昌和
<正> Vorticity, which represents the rotation of a fluid element, is an important characteristic of turbulence. Various methods have been used to measure vorticity. A hot-wire/hot-film anemometer (HWA) was used here to measure the vorticity in turbulent flows. The velocity components and their partial derivatives were simultaneously measured with a new 6-sensor hot-wire (HW) probe assuming ideal yaw and pitch factors with Jorgensen's expression and Taylor's hypothesis to analyze the data. The accurate 6-sensor hot-wire probe results for the velocity field were used to determine the velocity gradients and, therefore, the vorticity vector field. The data was measured in an isothermal model of a tangentially fired furnace. The experimental results in the tangentially fired furnace agree with numerical results.
2003年02期 215-223页 [查看摘要][在线阅读][下载 549k] [下载次数：50 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 何伯述,刁永发,许晋源,陈昌和
<正> Vorticity, which represents the rotation of a fluid element, is an important characteristic of turbulence. Various methods have been used to measure vorticity. A hot-wire/hot-film anemometer (HWA) was used here to measure the vorticity in turbulent flows. The velocity components and their partial derivatives were simultaneously measured with a new 6-sensor hot-wire (HW) probe assuming ideal yaw and pitch factors with Jorgensen's expression and Taylor's hypothesis to analyze the data. The accurate 6-sensor hot-wire probe results for the velocity field were used to determine the velocity gradients and, therefore, the vorticity vector field. The data was measured in an isothermal model of a tangentially fired furnace. The experimental results in the tangentially fired furnace agree with numerical results.
2003年02期 215-223页 [查看摘要][在线阅读][下载 549k] [下载次数：50 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] - 李克强,郑四发,杨殿阁,连小珉,永井正夫
<正> The conventional method for analyzing active suspension control for a vehicle is only to analyze a quarter or half car with a lower order degree-of-freedom (DOF) model, but such models do not actually model practical applications. Accurate models of a suspension control system require a multi-degree-of-freedom (MDOF) vehicle model with a detailed model of the controller. An MDOF model was developed including the influence of factors such as the engine, the seats, and the passengers to describe vehicle motion using a reduced order model of the controller designed by using the H∞ control method. The control system performance has been investigated by comparing the H∞controller with a linear quadratic (LQ) controller.
2003年02期 224-230页 [查看摘要][在线阅读][下载 282k] [下载次数：77 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 李克强,郑四发,杨殿阁,连小珉,永井正夫
<正> The conventional method for analyzing active suspension control for a vehicle is only to analyze a quarter or half car with a lower order degree-of-freedom (DOF) model, but such models do not actually model practical applications. Accurate models of a suspension control system require a multi-degree-of-freedom (MDOF) vehicle model with a detailed model of the controller. An MDOF model was developed including the influence of factors such as the engine, the seats, and the passengers to describe vehicle motion using a reduced order model of the controller designed by using the H∞ control method. The control system performance has been investigated by comparing the H∞controller with a linear quadratic (LQ) controller.
2003年02期 224-230页 [查看摘要][在线阅读][下载 282k] [下载次数：77 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 李克强,郑四发,杨殿阁,连小珉,永井正夫
<正> The conventional method for analyzing active suspension control for a vehicle is only to analyze a quarter or half car with a lower order degree-of-freedom (DOF) model, but such models do not actually model practical applications. Accurate models of a suspension control system require a multi-degree-of-freedom (MDOF) vehicle model with a detailed model of the controller. An MDOF model was developed including the influence of factors such as the engine, the seats, and the passengers to describe vehicle motion using a reduced order model of the controller designed by using the H∞ control method. The control system performance has been investigated by comparing the H∞controller with a linear quadratic (LQ) controller.
2003年02期 224-230页 [查看摘要][在线阅读][下载 282k] [下载次数：77 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 韩赞东,李基范
<正> Reachability analysis is an important approach for acquiring Petri net (PN) properties. The reachability tree and the solution of the state equation are two commonly used methods for reachability analysis, but they can result in state explosion and spurious solutions in some cases. As a significant complementary method, the PN reduction technique simplifies the reachability analysis by reducing the net size while preserving the reachability. This paper introduces several useful reduction rules and defines a reduction process for the analysis of reachability which is easy to understand and implement. Some examples are given to explain the method to solve the reachability problem. The analysis shows that the proposed reduction method preserves the visualization feature of PN and can be easily used.
2003年02期 231-235页 [查看摘要][在线阅读][下载 240k] [下载次数：44 ] |[网刊下载次数：0 ] |[引用频次：5 ] |[阅读次数：0 ] - 韩赞东,李基范
<正> Reachability analysis is an important approach for acquiring Petri net (PN) properties. The reachability tree and the solution of the state equation are two commonly used methods for reachability analysis, but they can result in state explosion and spurious solutions in some cases. As a significant complementary method, the PN reduction technique simplifies the reachability analysis by reducing the net size while preserving the reachability. This paper introduces several useful reduction rules and defines a reduction process for the analysis of reachability which is easy to understand and implement. Some examples are given to explain the method to solve the reachability problem. The analysis shows that the proposed reduction method preserves the visualization feature of PN and can be easily used.
2003年02期 231-235页 [查看摘要][在线阅读][下载 240k] [下载次数：44 ] |[网刊下载次数：0 ] |[引用频次：5 ] |[阅读次数：0 ] - 韩赞东,李基范
<正> Reachability analysis is an important approach for acquiring Petri net (PN) properties. The reachability tree and the solution of the state equation are two commonly used methods for reachability analysis, but they can result in state explosion and spurious solutions in some cases. As a significant complementary method, the PN reduction technique simplifies the reachability analysis by reducing the net size while preserving the reachability. This paper introduces several useful reduction rules and defines a reduction process for the analysis of reachability which is easy to understand and implement. Some examples are given to explain the method to solve the reachability problem. The analysis shows that the proposed reduction method preserves the visualization feature of PN and can be easily used.
2003年02期 231-235页 [查看摘要][在线阅读][下载 240k] [下载次数：44 ] |[网刊下载次数：0 ] |[引用频次：5 ] |[阅读次数：0 ] - 何云峰,都东,刘莹,岁波,熊丽娟
<正> To reduce friction and improve clarity of steel surfaces, laser texturing was used to produce known surface roughness profile on rolled surfaces using a Nd:YAG laser. Laser texturing process was analyzed to select the laser parameters. The surface roughness hardness and abrasion resistance were then measured and analyzed. The results show that the surface roughness is harder than the matrix, which fits for the requirements of laser texturing. The surface roughness also has good abrasion resistance. The intensity and distribution of the single pulse are the key points affecting the surface roughness profile.
2003年02期 236-240页 [查看摘要][在线阅读][下载 431k] [下载次数：52 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 何云峰,都东,刘莹,岁波,熊丽娟
<正> To reduce friction and improve clarity of steel surfaces, laser texturing was used to produce known surface roughness profile on rolled surfaces using a Nd:YAG laser. Laser texturing process was analyzed to select the laser parameters. The surface roughness hardness and abrasion resistance were then measured and analyzed. The results show that the surface roughness is harder than the matrix, which fits for the requirements of laser texturing. The surface roughness also has good abrasion resistance. The intensity and distribution of the single pulse are the key points affecting the surface roughness profile.
2003年02期 236-240页 [查看摘要][在线阅读][下载 431k] [下载次数：52 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] - 何云峰,都东,刘莹,岁波,熊丽娟
<正> To reduce friction and improve clarity of steel surfaces, laser texturing was used to produce known surface roughness profile on rolled surfaces using a Nd:YAG laser. Laser texturing process was analyzed to select the laser parameters. The surface roughness hardness and abrasion resistance were then measured and analyzed. The results show that the surface roughness is harder than the matrix, which fits for the requirements of laser texturing. The surface roughness also has good abrasion resistance. The intensity and distribution of the single pulse are the key points affecting the surface roughness profile.
2003年02期 236-240页 [查看摘要][在线阅读][下载 431k] [下载次数：52 ] |[网刊下载次数：0 ] |[引用频次：2 ] |[阅读次数：0 ] <正> A distinguished group of 100 experts from various universities and scientific research units in Asia,Australia,and North America attended the Tsinghua-Harvard Advanced Forum on Post-Colonialism June25,2002.
2003年02期 240页 [查看摘要][在线阅读][下载 55k] [下载次数：69 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] -
<正> A distinguished group of 100 experts from various universities and scientific research units in Asia,Australia,and North America attended the Tsinghua-Harvard Advanced Forum on Post-Colonialism June25,2002.
2003年02期 240页 [查看摘要][在线阅读][下载 55k] [下载次数：69 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ] <正> A distinguished group of 100 experts from various universities and scientific research units in Asia,Australia,and North America attended the Tsinghua-Harvard Advanced Forum on Post-Colonialism June25,2002.
2003年02期 240页 [查看摘要][在线阅读][下载 55k] [下载次数：69 ] |[网刊下载次数：0 ] |[引用频次：0 ] |[阅读次数：0 ]