Array configuration of multiple-input multiple-output (MIMO) radar with non-uniform linear array (NLA) is proposed. Unlike a standard phased-array radar where NLA is used to generate thinner beam patterns, in MIMO...Array configuration of multiple-input multiple-output (MIMO) radar with non-uniform linear array (NLA) is proposed. Unlike a standard phased-array radar where NLA is used to generate thinner beam patterns, in MIMO radar the property of NLA is exploited to get more distinct virtual array elements so as to improve pa- rameter identifiability, which means the maximum number of targets that can be uniquely identified by the radar. A class of NLA called minimum redundancy linear array (MRLA) is employed and a new method to construct large MRLAs is descrihed. The numerical results verify that compared to uniform linear array (ULA) MIMO radars, NLA MIMO radars can retain the same parameter identifiability with fewer physical antennas and achieve larger aperture length and lower Cramer-Rao bound with the same number of the physical antennas.展开更多
The effects of cyanidation conditions on gold dissolution were studied by artificial neural network (ANN) modeling. Eighty-five datasets were used to estimate the gold dissolution. Six input parameters, time, solid ...The effects of cyanidation conditions on gold dissolution were studied by artificial neural network (ANN) modeling. Eighty-five datasets were used to estimate the gold dissolution. Six input parameters, time, solid percentage, P50 of particle, NaCN content in cyanide media, temperature of solution and pH value were used. For selecting the best model, the outputs of models were compared with measured data. A fourth-layer ANN is found to be optimum with architecture of twenty, fifteen, ten and five neurons in the first, second, third and fourth hidden layers, respectively, and one neuron in output layer. The results of artificial neural network show that the square correlation coefficients (R2) of training, testing and validating data achieve 0.999 1, 0.996 4 and 0.9981, respectively. Sensitivity analysis shows that the highest and lowest effects on the gold dissolution rise from time and pH, respectively It is verified that the predicted values of ANN coincide well with the experimental results.展开更多
We propose in this paper the design of artificial nanostructure chirality obtained by oblique illumination. This structure is based on anisotropic metamaterial having an optical activity induced by the special geometr...We propose in this paper the design of artificial nanostructure chirality obtained by oblique illumination. This structure is based on anisotropic metamaterial having an optical activity induced by the special geometry of the pattern and the incident beam. Starting from a non-chiral material, the artificial chirality is obtained thanks to the rectangular apertures which form the periodic perfect metal nanostructure (one layer) and the oblique incidence of the light beam. An extraordinary light transmission (93%) through the metal nanostructure is achieved by exciting the cavity modes. The extrinsic chirality obtained can be granted to the desired value by appropriately adjusting the geometric parameters and the angle of incidence.展开更多
Traffic matrix is an abstract representation of the traffic volume flowing between sets of source and destination pairs.It is a key input parameter of network operations management,planning,provisioning and traffic en...Traffic matrix is an abstract representation of the traffic volume flowing between sets of source and destination pairs.It is a key input parameter of network operations management,planning,provisioning and traffic engineering.Traffic matrix is also important in the context of OpenFlow-based networks.Because even good measurement systems can suffer from errors and data collection systems can fail,missing values are common.Existing matrix completion methods do not consider traffic exhibit characteristics and only provide a finite precision.To address this problem,this paper proposes a novel approach based on compressive sensing and traffic self-similarity to reconstruct the missing traffic flow data.Firstly,we analyze the realworld traffic matrix,which all exhibit lowrank structure,temporal smoothness feature and spatial self-similarity.Then,we propose Self-Similarity and Temporal Compressive Sensing(SSTCS) algorithm to reconstruct the missing traffic data.The extensive experiments with the real-world traffic matrix show that our proposed SSTCS can significantly reduce data reconstruction errors and achieve satisfactory accuracy comparing with the existing solutions.Typically SSTCS can successfully reconstruct the traffic matrix with less than 32%errors when as much as98%of the data is missing.展开更多
This study involved investigating the sensitivity of Measures of Effectiveness (MOEs) to different simulation initialization time (7, 10, and 13 minutes); observing the trend of variation of MOEs with increasing s...This study involved investigating the sensitivity of Measures of Effectiveness (MOEs) to different simulation initialization time (7, 10, and 13 minutes); observing the trend of variation of MOEs with increasing simulation runs; and identifying the major contributors of variation in MOEs using CORSIM and SimTraffic. The results showed that (1) the MOEs of a simulated intersection approaches were indeed sensitive to initialization times; (2) the variation within MOEs reached a steady state with increased number of simulation runs, while CORSIM required at least 50 simulation runs, SimTraffic required even higher number of runs for congested approaches; (3) lane changing and gap acceptance parameters play a major role as a source of variation of MOEs (delay/vehicle) in CORSIM and SimTraffic respectively.展开更多
UWS (optimized Urea-Water Solution) injection system is required to increase the NH3 conversion efficiency of urea-based SCR (Selective Catalytic Reduction) system of modem automobiles. The focus of the current st...UWS (optimized Urea-Water Solution) injection system is required to increase the NH3 conversion efficiency of urea-based SCR (Selective Catalytic Reduction) system of modem automobiles. The focus of the current study is to do parametric studies by simulation in a three-dimensional model using CFD (Computational Fluid Dynamics) code AVL FIRE. Simulations were carried out to study the characteristics of evaporation and thermolysis UWS considering the effect of injection velocity, duration of injection, injection angle and for different types of injection. In the case of the injection velocities up to 20-50 m/sec, the ammonia concentration continues to increase. It is found that as the duration injection decreases, the concentration of ammonia increases. In case of continuous injection, the flow rate is less which results in lower velocity of injection, lesser atomization and slower evaporation resulting lesser conversion of UWS into NH3. Shorter duration of injection leads better atomization with increased velocity of injection which results in faster evaporation and thermolysis.展开更多
The success of any perimeter intrusion detection system depends on three important performance parameters: the probability of detection (POD), the nuisance alarm rate (NAR), and the false alarm rate (FAR). The ...The success of any perimeter intrusion detection system depends on three important performance parameters: the probability of detection (POD), the nuisance alarm rate (NAR), and the false alarm rate (FAR). The most fundamental parameter, POD, is normally related to a number of factors such as the event of interest, the sensitivity of the sensor, the installation quality of the system, and the reliability of the sensing equipment. The suppression of nuisance alarms without degrading sensitivity in fiber optic intrusion detection systems is key to maintaining acceptable performance. Signal processing algorithms that maintain the POD and eliminate nuisance alarms are crucial for achieving this. In this paper, a robust event classification system using supervised neural networks together with a level crossings (LCs) based feature extraction algorithm is presented for the detection and recognition of intrusion and non-intrusion events in a fence-based fiber-optic intrusion detection system. A level crossings algorithm is also used with a dynamic threshold to suppress torrential rain-induced nuisance alarms in a fence system. Results show that rain-induced nuisance alarms can be suppressed for rainfall rates in excess of 100mm/hr with the simultaneous detection of intrusion events. The use of a level crossing based detection and novel classification algorithm is also presented for a buried pipeline fiber optic intrusion detection system for the suppression of nuisance events and discrimination of intrusion events. The sensor employed for both types of systems is a distributed bidirectional fiber-optic Mach-Zehnder (MZ) interferometer.展开更多
The performance and emission characteristics of a PPCCI engine fuelled with ethanol and diesel blends were car- ded out on a single cylinder air cooled CI engine. In order to achieve the optimal process response with ...The performance and emission characteristics of a PPCCI engine fuelled with ethanol and diesel blends were car- ded out on a single cylinder air cooled CI engine. In order to achieve the optimal process response with a limited number of experimental cycles, multi objective grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a combination of input parameters was prefigured so as to achieve optimum response characteristics. It was observed that 20% premixed ratio of blend was most suitable for use in a PPCCI engine without significantly affecting the engine performance and emissions characteristics.展开更多
基金Supported by the Aeronautic Science Foundation of China(2008ZC52026)the Innovation Foundation of Nanjing University of Aeronautics and Astronautics~~
文摘Array configuration of multiple-input multiple-output (MIMO) radar with non-uniform linear array (NLA) is proposed. Unlike a standard phased-array radar where NLA is used to generate thinner beam patterns, in MIMO radar the property of NLA is exploited to get more distinct virtual array elements so as to improve pa- rameter identifiability, which means the maximum number of targets that can be uniquely identified by the radar. A class of NLA called minimum redundancy linear array (MRLA) is employed and a new method to construct large MRLAs is descrihed. The numerical results verify that compared to uniform linear array (ULA) MIMO radars, NLA MIMO radars can retain the same parameter identifiability with fewer physical antennas and achieve larger aperture length and lower Cramer-Rao bound with the same number of the physical antennas.
文摘The effects of cyanidation conditions on gold dissolution were studied by artificial neural network (ANN) modeling. Eighty-five datasets were used to estimate the gold dissolution. Six input parameters, time, solid percentage, P50 of particle, NaCN content in cyanide media, temperature of solution and pH value were used. For selecting the best model, the outputs of models were compared with measured data. A fourth-layer ANN is found to be optimum with architecture of twenty, fifteen, ten and five neurons in the first, second, third and fourth hidden layers, respectively, and one neuron in output layer. The results of artificial neural network show that the square correlation coefficients (R2) of training, testing and validating data achieve 0.999 1, 0.996 4 and 0.9981, respectively. Sensitivity analysis shows that the highest and lowest effects on the gold dissolution rise from time and pH, respectively It is verified that the predicted values of ANN coincide well with the experimental results.
文摘We propose in this paper the design of artificial nanostructure chirality obtained by oblique illumination. This structure is based on anisotropic metamaterial having an optical activity induced by the special geometry of the pattern and the incident beam. Starting from a non-chiral material, the artificial chirality is obtained thanks to the rectangular apertures which form the periodic perfect metal nanostructure (one layer) and the oblique incidence of the light beam. An extraordinary light transmission (93%) through the metal nanostructure is achieved by exciting the cavity modes. The extrinsic chirality obtained can be granted to the desired value by appropriately adjusting the geometric parameters and the angle of incidence.
基金This work is supported by the Prospcctive Research Project on Future Networks of Jiangsu Future Networks Innovation Institute under Grant No.BY2013095-1-05, the National Ba- sic Research Program of China (973) under Grant No. 2012CB315805 and the National Natural Science Foundation of China under Grants No. 61173167.
文摘Traffic matrix is an abstract representation of the traffic volume flowing between sets of source and destination pairs.It is a key input parameter of network operations management,planning,provisioning and traffic engineering.Traffic matrix is also important in the context of OpenFlow-based networks.Because even good measurement systems can suffer from errors and data collection systems can fail,missing values are common.Existing matrix completion methods do not consider traffic exhibit characteristics and only provide a finite precision.To address this problem,this paper proposes a novel approach based on compressive sensing and traffic self-similarity to reconstruct the missing traffic flow data.Firstly,we analyze the realworld traffic matrix,which all exhibit lowrank structure,temporal smoothness feature and spatial self-similarity.Then,we propose Self-Similarity and Temporal Compressive Sensing(SSTCS) algorithm to reconstruct the missing traffic data.The extensive experiments with the real-world traffic matrix show that our proposed SSTCS can significantly reduce data reconstruction errors and achieve satisfactory accuracy comparing with the existing solutions.Typically SSTCS can successfully reconstruct the traffic matrix with less than 32%errors when as much as98%of the data is missing.
文摘This study involved investigating the sensitivity of Measures of Effectiveness (MOEs) to different simulation initialization time (7, 10, and 13 minutes); observing the trend of variation of MOEs with increasing simulation runs; and identifying the major contributors of variation in MOEs using CORSIM and SimTraffic. The results showed that (1) the MOEs of a simulated intersection approaches were indeed sensitive to initialization times; (2) the variation within MOEs reached a steady state with increased number of simulation runs, while CORSIM required at least 50 simulation runs, SimTraffic required even higher number of runs for congested approaches; (3) lane changing and gap acceptance parameters play a major role as a source of variation of MOEs (delay/vehicle) in CORSIM and SimTraffic respectively.
文摘UWS (optimized Urea-Water Solution) injection system is required to increase the NH3 conversion efficiency of urea-based SCR (Selective Catalytic Reduction) system of modem automobiles. The focus of the current study is to do parametric studies by simulation in a three-dimensional model using CFD (Computational Fluid Dynamics) code AVL FIRE. Simulations were carried out to study the characteristics of evaporation and thermolysis UWS considering the effect of injection velocity, duration of injection, injection angle and for different types of injection. In the case of the injection velocities up to 20-50 m/sec, the ammonia concentration continues to increase. It is found that as the duration injection decreases, the concentration of ammonia increases. In case of continuous injection, the flow rate is less which results in lower velocity of injection, lesser atomization and slower evaporation resulting lesser conversion of UWS into NH3. Shorter duration of injection leads better atomization with increased velocity of injection which results in faster evaporation and thermolysis.
文摘The success of any perimeter intrusion detection system depends on three important performance parameters: the probability of detection (POD), the nuisance alarm rate (NAR), and the false alarm rate (FAR). The most fundamental parameter, POD, is normally related to a number of factors such as the event of interest, the sensitivity of the sensor, the installation quality of the system, and the reliability of the sensing equipment. The suppression of nuisance alarms without degrading sensitivity in fiber optic intrusion detection systems is key to maintaining acceptable performance. Signal processing algorithms that maintain the POD and eliminate nuisance alarms are crucial for achieving this. In this paper, a robust event classification system using supervised neural networks together with a level crossings (LCs) based feature extraction algorithm is presented for the detection and recognition of intrusion and non-intrusion events in a fence-based fiber-optic intrusion detection system. A level crossings algorithm is also used with a dynamic threshold to suppress torrential rain-induced nuisance alarms in a fence system. Results show that rain-induced nuisance alarms can be suppressed for rainfall rates in excess of 100mm/hr with the simultaneous detection of intrusion events. The use of a level crossing based detection and novel classification algorithm is also presented for a buried pipeline fiber optic intrusion detection system for the suppression of nuisance events and discrimination of intrusion events. The sensor employed for both types of systems is a distributed bidirectional fiber-optic Mach-Zehnder (MZ) interferometer.
文摘The performance and emission characteristics of a PPCCI engine fuelled with ethanol and diesel blends were car- ded out on a single cylinder air cooled CI engine. In order to achieve the optimal process response with a limited number of experimental cycles, multi objective grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a combination of input parameters was prefigured so as to achieve optimum response characteristics. It was observed that 20% premixed ratio of blend was most suitable for use in a PPCCI engine without significantly affecting the engine performance and emissions characteristics.