ISSN 
2003 Vol. 32, No. 2
2003, 32(2): 111-115.
Abstract:
With rapid development of the technologies and the standard of the third generation mobile communication,third-generation mobile telecom system have been one of the new and the hottest research spot in the communication field of the world.In the paper,the development of the mobile communication technology is introduced,and analyzes network architecture and protocol in the three 3G systems.The mainly technology question of the mobile communication in the construction is discussed. Finally,some key technologies of further development of mobile communications are discussed.
With rapid development of the technologies and the standard of the third generation mobile communication,third-generation mobile telecom system have been one of the new and the hottest research spot in the communication field of the world.In the paper,the development of the mobile communication technology is introduced,and analyzes network architecture and protocol in the three 3G systems.The mainly technology question of the mobile communication in the construction is discussed. Finally,some key technologies of further development of mobile communications are discussed.
2003, 32(2): 116-120,132.
Abstract:
A handoff strategy based on the area of a cell and the bit energy to interference density ratio is proposed in this paper,which is suited for hierarchical cell structured WCDMA system.A dynamic resource reservation scheme is applied in which new calls can use the reserved resource at certain probabilities.If the system has no idle resource in originating a handover call,the queueing mechnanism is adopted.From the results of simulation,the improvement in the blocking probabilities of voice is discovered,compared with the other handoff strategy adopting the fixed resource reservation.
A handoff strategy based on the area of a cell and the bit energy to interference density ratio is proposed in this paper,which is suited for hierarchical cell structured WCDMA system.A dynamic resource reservation scheme is applied in which new calls can use the reserved resource at certain probabilities.If the system has no idle resource in originating a handover call,the queueing mechnanism is adopted.From the results of simulation,the improvement in the blocking probabilities of voice is discovered,compared with the other handoff strategy adopting the fixed resource reservation.
2003, 32(2): 121-124.
Abstract:
This paper brings forward an optimizing memory algorithm by analyzing memory management.In communications equipments,memory management problems are often raised by mass message flow.The algorithm puts forward a series of solutions on these problems,including building user-defined memory management zone,designing optimized management queue,configuring memory structures according to the size of messages and providing protections on memory block.This design improves usage efficiency of memory resources and put an end to memory fragmentations as possible.
This paper brings forward an optimizing memory algorithm by analyzing memory management.In communications equipments,memory management problems are often raised by mass message flow.The algorithm puts forward a series of solutions on these problems,including building user-defined memory management zone,designing optimized management queue,configuring memory structures according to the size of messages and providing protections on memory block.This design improves usage efficiency of memory resources and put an end to memory fragmentations as possible.
2003, 32(2): 125-128.
Abstract:
Some thoroughly research on load state detection in SMSC entity is introduced in this paper. Load detection parameters and model are presented after analyzing the relationship between inter resource and load state in the system. Moreover, a novel strategy to detect system load state based on fusion of multi detection data is presented. By some test, the theory and method are proved most feasible. Our research show that load state of SMSC can be recognized by detecting utility of internal resource utilizing, and multi redundant detecting data fusion is effective approach to improve the reliability and trust degree of the result.
Some thoroughly research on load state detection in SMSC entity is introduced in this paper. Load detection parameters and model are presented after analyzing the relationship between inter resource and load state in the system. Moreover, a novel strategy to detect system load state based on fusion of multi detection data is presented. By some test, the theory and method are proved most feasible. Our research show that load state of SMSC can be recognized by detecting utility of internal resource utilizing, and multi redundant detecting data fusion is effective approach to improve the reliability and trust degree of the result.
2003, 32(2): 129-132.
Abstract:
In this paper, we bring forth a new optimal design method of fresnel diffractive lens using in light beam collimation of laser diode. By this way we can design high diffraction efficiency, as well as lager numerical aperture diffractive lens under current machine fabrication condition.
In this paper, we bring forth a new optimal design method of fresnel diffractive lens using in light beam collimation of laser diode. By this way we can design high diffraction efficiency, as well as lager numerical aperture diffractive lens under current machine fabrication condition.
2003, 32(2): 133-136.
Abstract:
This paper proposes a technique to design wideband digitized receiver based on polyphase filtering. The basic principle, design and FPGA implementation of polyphase filtering are discussed, and implementation project of wideband digitized receiver based on polyphase filtering is given. The results of computer simulation and FPGA simulation indicate that a technique to design wideband digitized receiver based on polyphase filtering is feasible,and can neatly implement wideband receiver which is difficult to be implemented by extant ASIC.
This paper proposes a technique to design wideband digitized receiver based on polyphase filtering. The basic principle, design and FPGA implementation of polyphase filtering are discussed, and implementation project of wideband digitized receiver based on polyphase filtering is given. The results of computer simulation and FPGA simulation indicate that a technique to design wideband digitized receiver based on polyphase filtering is feasible,and can neatly implement wideband receiver which is difficult to be implemented by extant ASIC.
2003, 32(2): 137-141.
Abstract:
A weight-feedback frequency domain adaptive filtering algorithm is proposed in this paper to suppress multi-narrowband interference. Using feedback weight adjusts timely the step during iterating procedure, fastens convergence rate of frequency adaptive filtering. Similarly this method can also achieve the purpose of suppressing interference and improving the performance of DSSS system. Compared with non-feedback frequency adaptive filtering, Mathematical derivation and computer simulation results are presented to validity of the proposed algorithm.
A weight-feedback frequency domain adaptive filtering algorithm is proposed in this paper to suppress multi-narrowband interference. Using feedback weight adjusts timely the step during iterating procedure, fastens convergence rate of frequency adaptive filtering. Similarly this method can also achieve the purpose of suppressing interference and improving the performance of DSSS system. Compared with non-feedback frequency adaptive filtering, Mathematical derivation and computer simulation results are presented to validity of the proposed algorithm.
2003, 32(2): 142-145.
Abstract:
In this paper, a square metal pole bandpass filter is designed based on the mode matching method. Then the square metal poles are replaced by cylindrical metal poles by using the empirical formula. This kind of filter has a simple structure and can be easily fabricated. So it is very suitable for quantity production. The calculated results are found to be in very good agreement with the experimental data, thus proves the precision of the mode matching method and the validity of the empirical formula.
In this paper, a square metal pole bandpass filter is designed based on the mode matching method. Then the square metal poles are replaced by cylindrical metal poles by using the empirical formula. This kind of filter has a simple structure and can be easily fabricated. So it is very suitable for quantity production. The calculated results are found to be in very good agreement with the experimental data, thus proves the precision of the mode matching method and the validity of the empirical formula.
2003, 32(2): 146-148,163.
Abstract:
A new design of low-noise low-power consumption charge sensitive amplifier is presented. Simulated by EDA software Cadence, the results obtained are satisfied. The DC open-loop gain is 82.9 dB with a 28 kHz -3 dB bandwidth and its phase margin is 46.9°. The maximum output noise spectral density is 1.5 μV/Hz2 at very low frequency. Using standard 3mm P-Well CMOS technology, the proposed amplifier is fabricated, and the measurement results are closed to the simulation.
A new design of low-noise low-power consumption charge sensitive amplifier is presented. Simulated by EDA software Cadence, the results obtained are satisfied. The DC open-loop gain is 82.9 dB with a 28 kHz -3 dB bandwidth and its phase margin is 46.9°. The maximum output noise spectral density is 1.5 μV/Hz2 at very low frequency. Using standard 3mm P-Well CMOS technology, the proposed amplifier is fabricated, and the measurement results are closed to the simulation.
2003, 32(2): 149-154.
Abstract:
In this work, a boundary element method was developed for the forward calculation of the source potential in a realistic head model. A high calculation precision is arrived through the use of the deflation technique and isolated problem approach. Based on the developed method, both source potential and the canonical cortical surface potential are calculated and compared, and the result indicates that the source potential is a better imaging modality than the cortical surface potential.
In this work, a boundary element method was developed for the forward calculation of the source potential in a realistic head model. A high calculation precision is arrived through the use of the deflation technique and isolated problem approach. Based on the developed method, both source potential and the canonical cortical surface potential are calculated and compared, and the result indicates that the source potential is a better imaging modality than the cortical surface potential.
2003, 32(2): 155-157.
Abstract:
This paper introduces motor's soft-starting controlling and preventing system based on MCS-51 80C31 8bit single-chip microcomputer. It presents work principle、hardware structure and software designing. The designing of soft-starting controlling and preventing system solves problems in moter starting and prolongs the longevity of motor.
This paper introduces motor's soft-starting controlling and preventing system based on MCS-51 80C31 8bit single-chip microcomputer. It presents work principle、hardware structure and software designing. The designing of soft-starting controlling and preventing system solves problems in moter starting and prolongs the longevity of motor.
2003, 32(2): 158-163.
Abstract:
In MAS environment, some key techniques are needed to realize interaction and cooperation of mobile Agents. In this paper, genetic algorithm is introduced to assign Agent to a suitable node, improved the coordination efficiency of Agents. An Agent communication language-knowledge query and manipulation language is analyzed and an Agent communication model is established based on knowledge query and manipulation language. Also, an effective way to solve Agent location tracing and invalidated communicating during Agent roaming among network nodes is provided.
In MAS environment, some key techniques are needed to realize interaction and cooperation of mobile Agents. In this paper, genetic algorithm is introduced to assign Agent to a suitable node, improved the coordination efficiency of Agents. An Agent communication language-knowledge query and manipulation language is analyzed and an Agent communication model is established based on knowledge query and manipulation language. Also, an effective way to solve Agent location tracing and invalidated communicating during Agent roaming among network nodes is provided.
2003, 32(2): 164-168.
Abstract:
In order to design the high safety of safety critical systems, in the paper, the nature of safety of safety critical systems was narrated in detail, established good theory foundation for designing high dependability safety critical systems. At the same time, realization mechanisms of safety were deeply discussed, and high safety safeguard technology based on safety kernel was emphatically researched. In order to realize safety kernel, a kind of programming language based on reflective theory——Open C++ was brought forward, exploring a new approach used to realize safety kernel, at the same time, a novel safeguard mechanism based on safety kernel is adaptable for other safety critical systems.
In order to design the high safety of safety critical systems, in the paper, the nature of safety of safety critical systems was narrated in detail, established good theory foundation for designing high dependability safety critical systems. At the same time, realization mechanisms of safety were deeply discussed, and high safety safeguard technology based on safety kernel was emphatically researched. In order to realize safety kernel, a kind of programming language based on reflective theory——Open C++ was brought forward, exploring a new approach used to realize safety kernel, at the same time, a novel safeguard mechanism based on safety kernel is adaptable for other safety critical systems.
2003, 32(2): 169-173.
Abstract:
This paper proposes a semi-formal,metric-based, problem-driven specification method to reduce the man-made effect and make the process of adopting design patterns on object-oriented software construction more automatically. Then, it demonstrates the method by redesigning an existed design of a streaming player via object-oriented method. Finally, it concludes the effect of this method on daily object oriented designing.
This paper proposes a semi-formal,metric-based, problem-driven specification method to reduce the man-made effect and make the process of adopting design patterns on object-oriented software construction more automatically. Then, it demonstrates the method by redesigning an existed design of a streaming player via object-oriented method. Finally, it concludes the effect of this method on daily object oriented designing.
2003, 32(2): 174-178.
Abstract:
This paper focuses on implementing security of large scale Active Networks on the Abone platform. We set up hop-by-hop security prototype framework with packet authentication and integrity by integrating many non-active components and traditional secure functions. We put forward hierarchy-distributed key and security association policy, and extend KLIPS and alarm indications. Finally, we compare LKH with EK using experiments, and conclude that LKH is suitable for the multicast members' revocation.
This paper focuses on implementing security of large scale Active Networks on the Abone platform. We set up hop-by-hop security prototype framework with packet authentication and integrity by integrating many non-active components and traditional secure functions. We put forward hierarchy-distributed key and security association policy, and extend KLIPS and alarm indications. Finally, we compare LKH with EK using experiments, and conclude that LKH is suitable for the multicast members' revocation.
2003, 32(2): 179-183.
Abstract:
The TCP performance on wireless link and the related works are introduced. A new scheme is proposed to improve the TCP performance over the wireless link on the direction from mobile host to fixed network. It installs a TCP agent at the base station to monitor the segments dropped on the wireless link, then triggers TCP fast retransmission on the MH side by replicating and forwarding specific ACKs, which can effectively avoid timeout retransmission. Simulation results show that the new scheme has favorable performance.
The TCP performance on wireless link and the related works are introduced. A new scheme is proposed to improve the TCP performance over the wireless link on the direction from mobile host to fixed network. It installs a TCP agent at the base station to monitor the segments dropped on the wireless link, then triggers TCP fast retransmission on the MH side by replicating and forwarding specific ACKs, which can effectively avoid timeout retransmission. Simulation results show that the new scheme has favorable performance.
2003, 32(2): 184-187.
Abstract:
Based on the discussion of state-of-art of firewall and its problem, discretionary access control model and mandatory access control model are designed. In order to prevent information leakage and denial of service, a multi-level reference model for firewall is proposed. The firewall reference model are analysed. The Implementation of the firewall based on the reference model is promoted in the end.
Based on the discussion of state-of-art of firewall and its problem, discretionary access control model and mandatory access control model are designed. In order to prevent information leakage and denial of service, a multi-level reference model for firewall is proposed. The firewall reference model are analysed. The Implementation of the firewall based on the reference model is promoted in the end.
2003, 32(2): 188-191,206.
Abstract:
According to the specification of CORBA, the architecture of bridge component and six kinds of models of the bridge were expatiated. These models lead to eight ways to create the bridge component. After analyzing the performance of these kinds of bridge, a user-defined bridge was applied to create a distributed system under UNIX and Windows that was originally set up under UNIX. The system was testified to be successful.
According to the specification of CORBA, the architecture of bridge component and six kinds of models of the bridge were expatiated. These models lead to eight ways to create the bridge component. After analyzing the performance of these kinds of bridge, a user-defined bridge was applied to create a distributed system under UNIX and Windows that was originally set up under UNIX. The system was testified to be successful.
2003, 32(2): 192-194.
Abstract:
In the management and development of large-scaled database, optimized design can improve its functions greatly. According to the discussion on performing query language of a large-scaled database, the authors propose an optimized design-optimizing multi-choice operation on the same form, choice operation on multi-forms, connection & choice operation on multi -forms, the using window and index. In practical application, the process of optimization, which is simple and effective, can decrease the amount of counting and internal storage, can speed up query execution and performance and has a stronger usage.
In the management and development of large-scaled database, optimized design can improve its functions greatly. According to the discussion on performing query language of a large-scaled database, the authors propose an optimized design-optimizing multi-choice operation on the same form, choice operation on multi-forms, connection & choice operation on multi -forms, the using window and index. In practical application, the process of optimization, which is simple and effective, can decrease the amount of counting and internal storage, can speed up query execution and performance and has a stronger usage.
2003, 32(2): 195-198.
Abstract:
A modified version of the finite-difference time-domain method with increased memory efficiency is applied to the computation of the radiation from a cylindrical monopole. And the graphical displays presented for the transient near-zone and far-zone radiation from the antenna provide physical insight into the radiation process. The novel approach compared with the normal finite-difference time-domain has higher efficiency.
A modified version of the finite-difference time-domain method with increased memory efficiency is applied to the computation of the radiation from a cylindrical monopole. And the graphical displays presented for the transient near-zone and far-zone radiation from the antenna provide physical insight into the radiation process. The novel approach compared with the normal finite-difference time-domain has higher efficiency.
2003, 32(2): 199-202.
Abstract:
Group oriented (t,n) threshold digital signature schemes have a problem in that the underlying signature schemes will be broken if any t or more shadowholders conspire together with each other,thus the group secret key will be revealed.The new scheme proposed by us can avoid the conspiracy attack.It is based on the difficulty of computing the discrete logarithm modulo for a composite number and the factorization problem of large integer.The size of the group signature and verification time of the group signature are equivalent to that of an individual signature.
Group oriented (t,n) threshold digital signature schemes have a problem in that the underlying signature schemes will be broken if any t or more shadowholders conspire together with each other,thus the group secret key will be revealed.The new scheme proposed by us can avoid the conspiracy attack.It is based on the difficulty of computing the discrete logarithm modulo for a composite number and the factorization problem of large integer.The size of the group signature and verification time of the group signature are equivalent to that of an individual signature.
2003, 32(2): 203-206.
Abstract:
Doping by nitrogen ion-implantation is used to fabricate the Ohmic contacts of 4H-SiC. The implantation depth profile is simulated with the Monte Carlo simulator TRIM. Ni/Cr/Si-face 4H-SiC Ohmic contacts are measured by Transfer Length Method structures. The result for sheet resistance Rsh of the implanted layers is 30 kΩ/square. The specific contact resistances ρc of Ohmic contacts is 7.1×10-4 Ωcm2.
Doping by nitrogen ion-implantation is used to fabricate the Ohmic contacts of 4H-SiC. The implantation depth profile is simulated with the Monte Carlo simulator TRIM. Ni/Cr/Si-face 4H-SiC Ohmic contacts are measured by Transfer Length Method structures. The result for sheet resistance Rsh of the implanted layers is 30 kΩ/square. The specific contact resistances ρc of Ohmic contacts is 7.1×10-4 Ωcm2.
2003, 32(2): 207-211.
Abstract:
In this paper the method of the design and the manufacture for the high g micro sensor array of the acceleration for the use of the fuse system are presented systematically, synthetically. It is applied the different method of the design and the technique for measuring the different value of the acceleration, and had the different sensor array in the manufacture of the micro sensor array of the acceleration. It is used the 3-D technique union of the 2-D technique of the integrated circuit. This sample meet the demand which is based upon this paper for the application.
In this paper the method of the design and the manufacture for the high g micro sensor array of the acceleration for the use of the fuse system are presented systematically, synthetically. It is applied the different method of the design and the technique for measuring the different value of the acceleration, and had the different sensor array in the manufacture of the micro sensor array of the acceleration. It is used the 3-D technique union of the 2-D technique of the integrated circuit. This sample meet the demand which is based upon this paper for the application.
2003, 32(2): 212-216.
Abstract:
The paper puts forward a set of faults diagnosis methods of testing the noise of the three-phase motor current which shows the characteristics of the motor faults. and multi-varieties time series models of the noise is established, the multi-varieties residual series is changed to the monistical as the fault detection index. In the fight of trait of the model parameter φi, presenting a faults classification recognition model based on the multi -layer NN structure, using APEX network extracts classification Information of the initial pattern vector,making use of feedforward network establishes the classification function. The diagnosis way is correct by practising.
The paper puts forward a set of faults diagnosis methods of testing the noise of the three-phase motor current which shows the characteristics of the motor faults. and multi-varieties time series models of the noise is established, the multi-varieties residual series is changed to the monistical as the fault detection index. In the fight of trait of the model parameter φi, presenting a faults classification recognition model based on the multi -layer NN structure, using APEX network extracts classification Information of the initial pattern vector,making use of feedforward network establishes the classification function. The diagnosis way is correct by practising.
2003, 32(2): 217-220.
Abstract:
According to SCM principals and choosing a mechanical manufacturing plant as prototype, the architecture of the plant'S supply chain is given out. The logistics is analyzed in detail by means of SCM concept and the model of the logistics management prototype system is established. The prototype system is designed adopting B/S and C/S mixed architecture. The tool-setup management subsystem is developed by VB language tool. The subsystem has been successfully used in this plant.
According to SCM principals and choosing a mechanical manufacturing plant as prototype, the architecture of the plant'S supply chain is given out. The logistics is analyzed in detail by means of SCM concept and the model of the logistics management prototype system is established. The prototype system is designed adopting B/S and C/S mixed architecture. The tool-setup management subsystem is developed by VB language tool. The subsystem has been successfully used in this plant.
2003, 32(2): 221-224.
Abstract:
In this paper the problem of artificial neural network model is studied. The differential equation of an artificial neural network model is solved by solving a simple one imension differential equation. Applying the solution of the neural network model, we proved that all solutions of a network from the unit hypersphere over Rn converge to the origin or a point in the sphere, when all of A's eigenvalues are less than or equal to zero as well as not all of the eigenvalues equal to zero.
In this paper the problem of artificial neural network model is studied. The differential equation of an artificial neural network model is solved by solving a simple one imension differential equation. Applying the solution of the neural network model, we proved that all solutions of a network from the unit hypersphere over Rn converge to the origin or a point in the sphere, when all of A's eigenvalues are less than or equal to zero as well as not all of the eigenvalues equal to zero.
