In theory, Log-Periodic Antenna (LPA) is a linearly polarized antenna with frequency independent properties on the input impedance and gain patterns. Owing to these characteristics, LPA has gained research interests a...In theory, Log-Periodic Antenna (LPA) is a linearly polarized antenna with frequency independent properties on the input impedance and gain patterns. Owing to these characteristics, LPA has gained research interests and been employed for many wideband applications. A Printed Log-Periodic Dipole Antenna (PLPDA) with multiple notched bands is proposed for Ultra-WideBand (UWB) applications. An antenna with the notched frequencies of 1.03 GHz, 1.28 GHz, 1.72 GHz, 2.24 GHz and 2.51 GHz is designed, fabricated, and measured. An antenna model was established on the substrate of FR4 and feed by a stripline. The simulation results show that the antenna can achieve an impendence wide bandwidth from 0.89 to 2.58 GHz with return loss less than -10 dB and exhibit stable antenna gain. Furthermore, the measurement result is better consistent with simulation result.展开更多
The interference alignment （IA） algorithm based on FDPM subspace tracking （FDPM-ST IA） is proposed for MIMO cognitive network （CRN） with multiple primary users in this paper. The feasibility conditions of FDPM-S...The interference alignment （IA） algorithm based on FDPM subspace tracking （FDPM-ST IA） is proposed for MIMO cognitive network （CRN） with multiple primary users in this paper. The feasibility conditions of FDPM-ST IA is also got. Futherly, IA scheme of secondary network and IA scheme of primary network are given respectively without assuming a priori knowledge of interference covariance matrices. Moreover, the paper analyses the computational complexity of FDPM-ST IA. Simulation results and theoretical calculations show that the proposed algorithm can achieve higher sum rate with lower computational complexity.展开更多
A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of th...A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.展开更多
The structural and electronic properties of (CdSe)_n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies...The structural and electronic properties of (CdSe)_n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies and highest occupied molecular orbital-lowest unoccupied molecular orbital gaps are compared with those obtained within local density approximation.展开更多
Vehicle management is a very important application area of GPS/GIS. Each customer has its special requirements on GIS system when he installs it. We discuss a common structure of our GPS/GIS implementation, and presen...Vehicle management is a very important application area of GPS/GIS. Each customer has its special requirements on GIS system when he installs it. We discuss a common structure of our GPS/GIS implementation, and present a case study on bulk concrete trucks management for bulk concrete producers. With GPS/GIS system, bulk concrete producers can improve their performance in scheduling and management.展开更多
Synchronization with lower SNR hadn't been considered by the conventional publications. Based on the Synchronized multi-carrier CDMA plus (SMCC+) system, which is one of the candidate schemes of digital terrestria...Synchronization with lower SNR hadn't been considered by the conventional publications. Based on the Synchronized multi-carrier CDMA plus (SMCC+) system, which is one of the candidate schemes of digital terrestrial TV broadcasting (DTTB) standard in China, a scheme under lower SNR with one short training sequence and one Barker code group, which were constructed in time domain. Computer simulation results show that the timing estimator here is designed to avoid the ambiguity which occured in Tufvesson's timing synchronization method. The 99.9% correct timing synchronization probability and lower false probability are got in AWGN and Rayleigh fading channels with SNR under -20 dB, and the optimum properties of frequency synchronization are obtained at the same time. It is shown that the proposed scheme is much better than the conventional synchronization methods.展开更多
Owing to the close correlation of development of oil and gas reservoir and spatial geological place, the technique of GIS can be introduced into the process of development and management of oil and gas reservoir. But ...Owing to the close correlation of development of oil and gas reservoir and spatial geological place, the technique of GIS can be introduced into the process of development and management of oil and gas reservoir. But development of oil and gas reservoir has its particularity, development and management GIS of oil and gas reservoir should use the other techniques to extend the forms of representation to make up the shortages of GIS in representation. The development and management GIS of oil and gas reservoir will be perfect besides the basic functions of GIS. This paper expatiates how to use other techniques to extend GIS in development and management of oil and gas reservoir mainly from productive dynamic curve of well, layers of map piling up, 3 D geological model and replaying maps, etc. Through extended GIS in development and management of oil and gas reservoir, the forms of representation of geological information are enriched, representations of information are more direct and visual, spatial descriptive ability and forms of representation of GIS are built up and the single information system will be developed into a management and decision making system.展开更多
With the rapid advance of wireless communication, tracking the positions of the moving objects is becoming increasingly feasible and necessary. Because a large number of people use mobile phones, we must handle a larg...With the rapid advance of wireless communication, tracking the positions of the moving objects is becoming increasingly feasible and necessary. Because a large number of people use mobile phones, we must handle a large moving object database as well as the following problems. How can we provide the customers with high quality service, that means, how can we deal with so many enquiries within as less time as possible? Because of the large number of data, the gap between CPU speed and the size of main memory has increasing considerably. One way to reduce the time to handle enquiries is to reduce the I/O number between the buffer and the secondary storage.An effective clustering of the objects can minimize the I/O cost between them. In this paper, according to the characteristic of the moving object database, we analyze the objects in buffer, according to their mappings in the two dimension coordinate, and then develop a density based clustering method to effectively reorganize the clusters. This new mechanism leads to the less cost of the I/O operation and the more efficient response to enquiries.展开更多
This contribution proposes a new symbol synchronization scheme for cyclicprefix based modulation systems, which is disclosed in Ref.. The proposed algorithm involves twosteps . By using short-time Fourier transform, I...This contribution proposes a new symbol synchronization scheme for cyclicprefix based modulation systems, which is disclosed in Ref.. The proposed algorithm involves twosteps . By using short-time Fourier transform, ISI-free intervals are estimated from time-frequencyspectrum of the received signal, and then an optimum symbol start time is obtained. Computersimulation results show that the algorithm is very robust, and outperforms those based upontime-domain correlations.展开更多
With the rapid growth of rate-based services and wirelessapplications, improving Transmission Control Protocol(TCP)congestioncontrol has been becoming more important in the network researchfield. This paper first Brie...With the rapid growth of rate-based services and wirelessapplications, improving Transmission Control Protocol(TCP)congestioncontrol has been becoming more important in the network researchfield. This paper first Briefly introduces the Additive-IncreaseMultiplicative-Decrease(AIMD)(a,b)algorithm, and then presents an im-Proved TCP congestion control mechanism(D-AIMD)whose principles andsimulation results are discussed in detail. This mechanism can beeasily implemented with lower additional overheads and canefficiently improve network per- Formance.展开更多
This paper presents a novel framework for IP Differentiated Services (DiffServ) over optical burst switching (OBS), namely, DS-OBS. The network architecture, functional model of edge nodes and core nodes, the control ...This paper presents a novel framework for IP Differentiated Services (DiffServ) over optical burst switching (OBS), namely, DS-OBS. The network architecture, functional model of edge nodes and core nodes, the control packet format, a novel burst assembly scheme at ingress nodes and scheduling algorithm of core nodes are presented. The basic idea is to apply DiffServ capable burst assembly at ingress nodes and perform different per hop behavior (PHB) electronic treatments for control packets of different QoS class services at core nodes. Simulation results show that the proposed schemes can provide the best differentiated service for expedited forwarding (EF), assured forwarding (AF) and best effort (BE) services in terms of end-to-end delay, throughput and IP packet loss probability. Keywords IP quality of service - differentiated service - per hop behavior - optical burst switching NoteThis work is supported by the National Natural Science Foundation of China (Grant No.90304004), the National Hi-Tech Development 863 Program of China (Grant No.2003AA121540), and the research grants by the Ministry of Education of China (Grant No.204125), the Chongqing Education Commission (Grant No.050309) and the Chongqing Science Commission.展开更多
It is very easy to design an observer for a discrete chaotic system which possesses one non linear scalar quantity, and one can realize the synchronization between the investigated chaotic system and its observer eas...It is very easy to design an observer for a discrete chaotic system which possesses one non linear scalar quantity, and one can realize the synchronization between the investigated chaotic system and its observer easily. This method is applied to two chaotic systems.展开更多
This paper mainly focuses on performance analysis of the previously proposedSTFT based 2-D timing approach to OFDM systems and presents simulations results of its performancein AWGN and multipath fading environment an...This paper mainly focuses on performance analysis of the previously proposedSTFT based 2-D timing approach to OFDM systems and presents simulations results of its performancein AWGN and multipath fading environment and its robustness against the duration of Channel ImpulseResponse (CIR) and frequency offset. Simulation results suggest that a revised version of Short-TimeFourier Transform (STFT) can be used to greatly reduce computational complexity, especially athigher SNR.展开更多
Telecommunication networks will become IP based networks with all voice, data and multimedia traffic carried as packets with appropriate quality and class of service for each traffic type. It is very important fo...Telecommunication networks will become IP based networks with all voice, data and multimedia traffic carried as packets with appropriate quality and class of service for each traffic type. It is very important for service provider to apply Traffic Engineering ( TE ) with the dramatic growth of networks traffic. In this paper, we discuss traffic engineering based on IP/MPLS and emphasize traffic measurement in telecom core networks. We specify the technology and scientific principles of the measurement, modeling, characterization, and the traffic flow matrix. The paper concludes with a preliminary analysis of TE measurement and a discussion about the development of TE measurement.展开更多
Abstract: Seven hundred and fourteen individuals of the Scilla sinensis (Louriro) Merrill complex were sampled from 21 populations at 19 localities in 10 provinces and two cities of China and investigated cytologicall...Abstract: Seven hundred and fourteen individuals of the Scilla sinensis (Louriro) Merrill complex were sampled from 21 populations at 19 localities in 10 provinces and two cities of China and investigated cytologically in order to test its cytotype composition and cytogeographical variation still further. Five cytotypes were found (i.e. AA (2n = 16), BB (2n = 18), AABB (2n = 34), AAA (2n = 24), and AABB+9 (2n = 43)). Until now, nine of the 12 cytotypes have been identified on the continent, which indicates that it is an important place for the cytotypic differentiation of the complex. The cytotype AABB+9 is a new record on the continent. AAA was recorded for the second time in this complex. The majority of populations are composed of only one cytotype (AA, BB, or AABB), whereas another four populations consist of more than two cytotypes involving AA, BB, AAA, AABB, and AABB+9. The distribution of BB covers the entire region south to Huai River, whereas AA populations are distributed in Taiwan, Fujian, Hong Kong, and Guangdong and are isolated from its major distribution. The appearance of AABB+9 is possibly evidence for the degeneration of the subglobular bulb type of AABB and the fact that AAA and AAAA exist in the interior border regions of the range of this complex probably suggests that drought is a major factor promoting plant polyploidization. In addition, the mean numbers of B chromosomes per individual, the percentage of individuals with the B chromosome in each population, and the correlation coefficients between the latter and their latitude/longitude were calculated. Generally speaking, the B chromosome number is higher in BB populations compared with AA populations and there is a prominent tendency that the B chromosome content in either AA or BB populations correlates with the latitude and longitude of the populations.展开更多
Bioosting e-stamp's advantages are conduced to promote logisticsto go forward and help postal depart- ments to improve the quality ofservice, many other businesses add-valued can be developed in e-stampsystems. Th...Bioosting e-stamp's advantages are conduced to promote logisticsto go forward and help postal depart- ments to improve the quality ofservice, many other businesses add-valued can be developed in e-stampsystems. This paper analyzeds, designs e-commerce-object e-stampsystem, and discussed crucial technologies involved in detail.展开更多
Postal departments are actively taking part in e commerce, of which logistics is a key joint. Computerized routing and scheduling of postal transportation operations offers significant potential for cost decreases an...Postal departments are actively taking part in e commerce, of which logistics is a key joint. Computerized routing and scheduling of postal transportation operations offers significant potential for cost decreases and productivity gains. Routing and scheduling hierarchy model is initially built and demonstrated in detail on the basis of statements of specific requirements of postal logistics in this paper, and the realized software is proved to be practical and reliable.展开更多
The Travelling Salesman Problem ( TSP ) is one of the most difficult problems that many scholars all over the world are studying. This paper points out the disparity between the definition and the classical solution...The Travelling Salesman Problem ( TSP ) is one of the most difficult problems that many scholars all over the world are studying. This paper points out the disparity between the definition and the classical solution to TSP and its practical applications, and then presents a new definition of TSP and its effective algorithm conforming to practical applications, thus making TSP practically more valuable.展开更多
文摘In theory, Log-Periodic Antenna (LPA) is a linearly polarized antenna with frequency independent properties on the input impedance and gain patterns. Owing to these characteristics, LPA has gained research interests and been employed for many wideband applications. A Printed Log-Periodic Dipole Antenna (PLPDA) with multiple notched bands is proposed for Ultra-WideBand (UWB) applications. An antenna with the notched frequencies of 1.03 GHz, 1.28 GHz, 1.72 GHz, 2.24 GHz and 2.51 GHz is designed, fabricated, and measured. An antenna model was established on the substrate of FR4 and feed by a stripline. The simulation results show that the antenna can achieve an impendence wide bandwidth from 0.89 to 2.58 GHz with return loss less than -10 dB and exhibit stable antenna gain. Furthermore, the measurement result is better consistent with simulation result.
基金the National Nature Science Foundation of China under Grant No.61271259 and 61301123,the Chongqing Nature Science Foundation under Grant No.CTSC2011jjA40006,and the Research Project of Chongqing Education Commission under Grant No.KJ120501 and KJ120502
文摘The interference alignment （IA） algorithm based on FDPM subspace tracking （FDPM-ST IA） is proposed for MIMO cognitive network （CRN） with multiple primary users in this paper. The feasibility conditions of FDPM-ST IA is also got. Futherly, IA scheme of secondary network and IA scheme of primary network are given respectively without assuming a priori knowledge of interference covariance matrices. Moreover, the paper analyses the computational complexity of FDPM-ST IA. Simulation results and theoretical calculations show that the proposed algorithm can achieve higher sum rate with lower computational complexity.
文摘A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.
文摘The structural and electronic properties of (CdSe)_n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies and highest occupied molecular orbital-lowest unoccupied molecular orbital gaps are compared with those obtained within local density approximation.
基金This work is supported in part by Chongqing Science Fund # 774 2 - 4 China and by U niversity ITResearch Center ProjectKorea
文摘Vehicle management is a very important application area of GPS/GIS. Each customer has its special requirements on GIS system when he installs it. We discuss a common structure of our GPS/GIS implementation, and present a case study on bulk concrete trucks management for bulk concrete producers. With GPS/GIS system, bulk concrete producers can improve their performance in scheduling and management.
文摘Synchronization with lower SNR hadn't been considered by the conventional publications. Based on the Synchronized multi-carrier CDMA plus (SMCC+) system, which is one of the candidate schemes of digital terrestrial TV broadcasting (DTTB) standard in China, a scheme under lower SNR with one short training sequence and one Barker code group, which were constructed in time domain. Computer simulation results show that the timing estimator here is designed to avoid the ambiguity which occured in Tufvesson's timing synchronization method. The 99.9% correct timing synchronization probability and lower false probability are got in AWGN and Rayleigh fading channels with SNR under -20 dB, and the optimum properties of frequency synchronization are obtained at the same time. It is shown that the proposed scheme is much better than the conventional synchronization methods.
文摘Owing to the close correlation of development of oil and gas reservoir and spatial geological place, the technique of GIS can be introduced into the process of development and management of oil and gas reservoir. But development of oil and gas reservoir has its particularity, development and management GIS of oil and gas reservoir should use the other techniques to extend the forms of representation to make up the shortages of GIS in representation. The development and management GIS of oil and gas reservoir will be perfect besides the basic functions of GIS. This paper expatiates how to use other techniques to extend GIS in development and management of oil and gas reservoir mainly from productive dynamic curve of well, layers of map piling up, 3 D geological model and replaying maps, etc. Through extended GIS in development and management of oil and gas reservoir, the forms of representation of geological information are enriched, representations of information are more direct and visual, spatial descriptive ability and forms of representation of GIS are built up and the single information system will be developed into a management and decision making system.
基金This work is supported by University IT Research Center Project in KOREA.
文摘With the rapid advance of wireless communication, tracking the positions of the moving objects is becoming increasingly feasible and necessary. Because a large number of people use mobile phones, we must handle a large moving object database as well as the following problems. How can we provide the customers with high quality service, that means, how can we deal with so many enquiries within as less time as possible? Because of the large number of data, the gap between CPU speed and the size of main memory has increasing considerably. One way to reduce the time to handle enquiries is to reduce the I/O number between the buffer and the secondary storage.An effective clustering of the objects can minimize the I/O cost between them. In this paper, according to the characteristic of the moving object database, we analyze the objects in buffer, according to their mappings in the two dimension coordinate, and then develop a density based clustering method to effectively reorganize the clusters. This new mechanism leads to the less cost of the I/O operation and the more efficient response to enquiries.
文摘This contribution proposes a new symbol synchronization scheme for cyclicprefix based modulation systems, which is disclosed in Ref.. The proposed algorithm involves twosteps . By using short-time Fourier transform, ISI-free intervals are estimated from time-frequencyspectrum of the received signal, and then an optimum symbol start time is obtained. Computersimulation results show that the algorithm is very robust, and outperforms those based upontime-domain correlations.
文摘With the rapid growth of rate-based services and wirelessapplications, improving Transmission Control Protocol(TCP)congestioncontrol has been becoming more important in the network researchfield. This paper first Briefly introduces the Additive-IncreaseMultiplicative-Decrease(AIMD)(a,b)algorithm, and then presents an im-Proved TCP congestion control mechanism(D-AIMD)whose principles andsimulation results are discussed in detail. This mechanism can beeasily implemented with lower additional overheads and canefficiently improve network per- Formance.
文摘This paper presents a novel framework for IP Differentiated Services (DiffServ) over optical burst switching (OBS), namely, DS-OBS. The network architecture, functional model of edge nodes and core nodes, the control packet format, a novel burst assembly scheme at ingress nodes and scheduling algorithm of core nodes are presented. The basic idea is to apply DiffServ capable burst assembly at ingress nodes and perform different per hop behavior (PHB) electronic treatments for control packets of different QoS class services at core nodes. Simulation results show that the proposed schemes can provide the best differentiated service for expedited forwarding (EF), assured forwarding (AF) and best effort (BE) services in terms of end-to-end delay, throughput and IP packet loss probability. Keywords IP quality of service - differentiated service - per hop behavior - optical burst switching NoteThis work is supported by the National Natural Science Foundation of China (Grant No.90304004), the National Hi-Tech Development 863 Program of China (Grant No.2003AA121540), and the research grants by the Ministry of Education of China (Grant No.204125), the Chongqing Education Commission (Grant No.050309) and the Chongqing Science Commission.
文摘It is very easy to design an observer for a discrete chaotic system which possesses one non linear scalar quantity, and one can realize the synchronization between the investigated chaotic system and its observer easily. This method is applied to two chaotic systems.
文摘This paper mainly focuses on performance analysis of the previously proposedSTFT based 2-D timing approach to OFDM systems and presents simulations results of its performancein AWGN and multipath fading environment and its robustness against the duration of Channel ImpulseResponse (CIR) and frequency offset. Simulation results suggest that a revised version of Short-TimeFourier Transform (STFT) can be used to greatly reduce computational complexity, especially athigher SNR.
文摘Telecommunication networks will become IP based networks with all voice, data and multimedia traffic carried as packets with appropriate quality and class of service for each traffic type. It is very important for service provider to apply Traffic Engineering ( TE ) with the dramatic growth of networks traffic. In this paper, we discuss traffic engineering based on IP/MPLS and emphasize traffic measurement in telecom core networks. We specify the technology and scientific principles of the measurement, modeling, characterization, and the traffic flow matrix. The paper concludes with a preliminary analysis of TE measurement and a discussion about the development of TE measurement.
文摘Abstract: Seven hundred and fourteen individuals of the Scilla sinensis (Louriro) Merrill complex were sampled from 21 populations at 19 localities in 10 provinces and two cities of China and investigated cytologically in order to test its cytotype composition and cytogeographical variation still further. Five cytotypes were found (i.e. AA (2n = 16), BB (2n = 18), AABB (2n = 34), AAA (2n = 24), and AABB+9 (2n = 43)). Until now, nine of the 12 cytotypes have been identified on the continent, which indicates that it is an important place for the cytotypic differentiation of the complex. The cytotype AABB+9 is a new record on the continent. AAA was recorded for the second time in this complex. The majority of populations are composed of only one cytotype (AA, BB, or AABB), whereas another four populations consist of more than two cytotypes involving AA, BB, AAA, AABB, and AABB+9. The distribution of BB covers the entire region south to Huai River, whereas AA populations are distributed in Taiwan, Fujian, Hong Kong, and Guangdong and are isolated from its major distribution. The appearance of AABB+9 is possibly evidence for the degeneration of the subglobular bulb type of AABB and the fact that AAA and AAAA exist in the interior border regions of the range of this complex probably suggests that drought is a major factor promoting plant polyploidization. In addition, the mean numbers of B chromosomes per individual, the percentage of individuals with the B chromosome in each population, and the correlation coefficients between the latter and their latitude/longitude were calculated. Generally speaking, the B chromosome number is higher in BB populations compared with AA populations and there is a prominent tendency that the B chromosome content in either AA or BB populations correlates with the latitude and longitude of the populations.
文摘Bioosting e-stamp's advantages are conduced to promote logisticsto go forward and help postal depart- ments to improve the quality ofservice, many other businesses add-valued can be developed in e-stampsystems. This paper analyzeds, designs e-commerce-object e-stampsystem, and discussed crucial technologies involved in detail.
文摘Postal departments are actively taking part in e commerce, of which logistics is a key joint. Computerized routing and scheduling of postal transportation operations offers significant potential for cost decreases and productivity gains. Routing and scheduling hierarchy model is initially built and demonstrated in detail on the basis of statements of specific requirements of postal logistics in this paper, and the realized software is proved to be practical and reliable.
文摘The Travelling Salesman Problem ( TSP ) is one of the most difficult problems that many scholars all over the world are studying. This paper points out the disparity between the definition and the classical solution to TSP and its practical applications, and then presents a new definition of TSP and its effective algorithm conforming to practical applications, thus making TSP practically more valuable.
