A 5×5 broadside slot array backed by a single cavity containing a mode filter is designed. The resonant slot length is obtained by using a waveguide slot model. The simulated and measured results show that this a...
A 5×5 broadside slot array backed by a single cavity containing a mode filter is designed. The resonant slot length is obtained by using a waveguide slot model. The simulated and measured results show that this array achieves more than 8% -10dB return loss and 3dB gain bandwidth.
Wideband signal detection plays an important role in wireless communication systems. In recent years, deep learning (DL) has been introduced, and many trial efforts have been posed. In this paper, a fast deep-learning...
Wideband signal detection plays an important role in wireless communication systems. In recent years, deep learning (DL) has been introduced, and many trial efforts have been posed. In this paper, a fast deep-learning signal detection architecture is proposed for the short-wave band, which consists of the GPU-based Down Digital Converter (DDC), the DL-based signal detector, and the signal data viewer & recorder. Wideband signal data are taken directly as the input, and detected signals are automatically recorded as the output of the architecture. Experimental results suggest that our architecture is capable of detecting signals in the whole short-wave band in quasi-real-time, and specifically, with single GPU device.
The problem of stationary target location by multiple passive radar sensors that using unknown and non-cooperative opportunity illuminator is considered. Traditional twostep approach which estimating the time differen...
详细信息
The problem of stationary target location by multiple passive radar sensors that using unknown and non-cooperative opportunity illuminator is considered. Traditional twostep approach which estimating the time difference of arrival(TDOA) and angle of arrival(AOA) firstly and locating using those parameters secondly. We explore the direct location with multiple passive radar sensors without estimating the intermediate parameters. As the reference path from the transmitter to receivers may be blocked in practice, we discuss the both cases that location without and with reference path. Two maximum likelihood algorithms of direct location are proposed for multiple passive radar sensors without and with reference. Monte Carlo simulations indicate that the direct location algorithm is superior to two-step approach with TDOA and AOA at low SNR for multiple passive radar sensors.
The low altitude, slow speed and small size object which we call LSS-object for short, such as small UAV(unmanned aerial vehicles) have become a hot issue of air defense security, which is difficult to detect and iden...
详细信息
The low altitude, slow speed and small size object which we call LSS-object for short, such as small UAV(unmanned aerial vehicles) have become a hot issue of air defense security, which is difficult to detect and identify accurately from the image. In this paper, aiming at the problem of LSS-object detection under noise environment, the detection method based on deep learning is proposed. Firstly, a standard training dataset consisting 5 classes of typical objects is constructed. Then, the standard dataset is augmented with noise of different intensity. Finally, YOLO v3 algorithm is used to form a LSS-object detection system which can adapt to environment noise. The training and detection experiments were carried out on the GPU server. After only using the noise-free dataset for training, the mAP(mean Average Precision) of the noise-free test set detection reached 81.07%, but the mAP decreased to 20.68% when the noise variance was *** adopting the mixed training strategy of the dataset with noise variance of 0.01 and noise-free data, the mAP for the test set detection with noise variance of 0.03 was increased to 70.61%, and the mAP still reached 79.85% in noise-free test set detection. The experiment results show that the mixed training strategy can greatly improve the accuracy in the noisy images detection while maintaining a higher accuracy in noise-free images.
With the increasing deployment of various medium, the transmission performance has become a key issue of the Internet research. An important impact on the performance is the packet reordering, which is well-known in p...
详细信息
Completing networks is often a necessary step when dealing with problems arising from applications in incomplete network data mining. This paper investigates the network completion problem with node attributes. We pro...
Completing networks is often a necessary step when dealing with problems arising from applications in incomplete network data mining. This paper investigates the network completion problem with node attributes. We proposed a new method called DeepMetricNC by exploiting the correlation between node attributes and the underlying network structure. In DeepMetricNC, the correlation is modeled as a nonlinear mapping from node attributes to the probability of edge existence. To obtain the mapping, deep metric learning is applied with batch training and random negative sampling. DeepMetricNC has linear training time complexity and can adapt to large-scale network completion tasks. Experiments of real networks show that DeepMetricNC completes network structures better than other methods, and is more suitable when the portion of the observed part is small.
With the popularity of the mobile phones and location-based social networks, rich location data has become widely available nowadays, enabling study on friendship detection based on human mobility. However, in some ci...
详细信息
ISBN:
(纸本)9781509038237;9781509038220
With the popularity of the mobile phones and location-based social networks, rich location data has become widely available nowadays, enabling study on friendship detection based on human mobility. However, in some circumstances, limited by data collection techniques, only discrete location(such as location IDs) can be fetched which leads to methods of detecting friendship based on distance metric is unrealistic. This paper aims to detect friendship among users based on their mobility data where locations are represented by location IDs. By considering each user’s preference for location and each location’s popularity, the difference between friends and strangers gets larger than using merely frequency of meeting events. However, we discover that measure values obtained may vary greatly among different users and propose to maintain a threshold for each user. In addition, an online updating algorithm is presented to update thresholds when a new user’s mobility data is available. Experiments conducted on MIT Reality Mining project dataset show that the proposed updating method is practical and the proposed multi-threshold model outperforms the state-of-theart methods proposed by Wang et al.
This paper considers the problem of geolocating a target on the Earth surface whose altitude is known using the target signal time of arrival(TOA) measurements. The geolocation Cramer-Rao lower bound(CRLB) is derived ...
详细信息
This paper considers the problem of geolocating a target on the Earth surface whose altitude is known using the target signal time of arrival(TOA) measurements. The geolocation Cramer-Rao lower bound(CRLB) is derived and the performance improvement due to the availability of target altitude information is quantified. An weighted multidimensional scaling geolocation solution is developed. Its sensitivity to the target altitude error is also studied. Simulations verify the theoretical developments and illustrate the good performance of the proposed geolocation method.
An optimum strategy of reference emitter placement for dual-satellite time difference of arrival (TDOA) and frequency difference of arrival (FDOA) localization based on particle swarm optimization is proposed to impro...
ISBN:
(数字)9781538682463
ISBN:
(纸本)9781538682470
An optimum strategy of reference emitter placement for dual-satellite time difference of arrival (TDOA) and frequency difference of arrival (FDOA) localization based on particle swarm optimization is proposed to improve localization accuracy. Firstly Cramer-Rao lower bound (CRLR) of dual-satellite TDOA and FDOA localization system with ephemeris error and system error is derived. Then, the optimum strategy of reference emitter placement is transformed to multidimensional constraint optimization problem by using CRLB as the criterion for performance of dual-satellite TDOA and FDOA localization system. Finally, optimum strategy of reference emitter placement is obtained by using particle swarm optimization (PSO) to solve the target function. Simulation results demonstrate that the proposed method can derive optimum strategy of reference emitter placement validly. Besides, when the optimum strategy of reference emitter placement is applied, only two reference emitters are demanded to eliminate the effect of ephemeris error and system error on localization accuracy.
The low altitude, slow speed and small size object which we call LSS-object for short, such as small UAV (unmanned aerial vehicles) have become a hot issue of air defense security, which is difficult to detect and ide...
The low altitude, slow speed and small size object which we call LSS-object for short, such as small UAV (unmanned aerial vehicles) have become a hot issue of air defense security, which is difficult to detect and identify accurately from the image. In this paper, aiming at the problem of LSS-object detection under noise environment, the detection method based on deep learning is proposed. Firstly, a standard training dataset consisting 5 classes of typical objects is constructed. Then, the standard dataset is augmented with noise of different intensity. Finally, YOLO v3 algorithm is used to form a LSS-object detection system which can adapt to environment noise. The training and detection experiments were carried out on the GPU server. After only using the noise-free dataset for training, the mAP(mean Average Precision) of the noise-free test set detection reached 81.07%, but the mAP decreased to 20.68% when the noise variance was *** adopting the mixed training strategy of the dataset with noise variance of 0.01 and noise-free data, the mAP for the test set detection with noise variance of 0.03 was increased to 70.61%, and the mAP still reached 79.85% in noise-free test set detection. The experiment results show that the mixed training strategy can greatly improve the accuracy in the noisy images detection while maintaining a higher accuracy in noise-free images.
暂无评论