The measurement of an emitter's position using electronic support passive sensors is termed passive localization and plays an important part both in electronic support and electronic attack. The ...emitting target could be in terrestrial or underwater environment. In this paper, we propose a time difference of arrival (TDoA) algorithm for passive localization in underwater and terrestrial environment. In terrestrial environment, it is assumed that a Rician flat fading model should be used because there exists line of sight. In underwater environment, we apply a modified UWB Saleh-Valenzuela (S-V) model to characterize the underwater acoustic fading channel. We propose the TDoA finding algorithm via estimating the delay of two correlated channels, and compare it with the existing approach. Simulations were conducted for terrestrial and underwater environment, and simulation results show that our TDoA algorithm performs much better than the cross-correlation-based TDoA algorithm with a lower level of magnitude in terms of average TDoA error and root-mean-square error (RMSE). Compared to the TDoA performance in terrestrial environment, the TDoA performance in underwater environment is much worse. This is because the underwater channel has clusters and rays, which introduces memory and uncertainties. For the two scenarios in underwater environment, the performance in rich scattering underwater environment is worse than that in less scattering underwater environment, because the latter has less clusters and rays, which would cause less uncertainties in TDoA.
In hyperspectral transmission imaging (mainly refers to transmission breast imaging), the strong scattering characteristics of the tissue cause the blurred image and weak image signal, which hinders ...heterogeneity detection in tissue. In this paper, we designed the simulation experiment of collecting phantom images, and a joint preprocessing algorithm suitable for transmission tissue image is proposed and verified: the algorithm combining single channel frame accumulation and edge enhancement algorithm. The result shows that the PSNR of the phantom image is increased to 57.3 dB and the edge of phantom image processed by the joint preprocessing algorithm is preserved; the standard deviation is 19.8998 higher than original image, that is, the contrast is greatly improved. In our previous work, the detection accuracy of the image processed by this algorithm is higher than that without processed when the image detected in object detection algorithm based on deep learning; the mAP reaches 99.9%. Therefore, the preprocessing algorithm in this paper provides a highly compatible and easier preprocessing method for heterogeneity detection of multispectral tissue images, which improves the detection accuracy of heterogeneity to some extent. And it may be a new way to improve the quality of such multispectral and hyperspectral transmission tissue images.
For integrated sensing and communication, one important research direction is to employ various beamforming techniques to avoid interference between the two functions. In this work, based on a hybrid ...beamforming antenna array structure, a physical layer security technique called directional modulation (DM) is studied for multi-beam multiplexing applications. The proposed design can form a more effective directional transmission through both beamforming and DM, while multiplexing multiple user beams through a common set of analog coefficients. In this hybrid beamforming structure, only one digital-to-analog converter (DAC) is connected to each subarray, and finite-precision phase shifters are further considered. Design examples for dual-beam multiplexing with an interleaved subarray structure and a localized subarray structure, respectively, are provided, which show that the interleaved subarray structure can form narrower mainlobe and a lower sidelobe level than the localized structure and has an overall better performance.
As a new type of data, data stream has the characteristics of massive, high-speed, orderly, and continuous and is widely distributed in sensor networks, mobile communication, financial transactions, ...network traffic analysis, and other fields. However, due to the inherent problem of concept drift, it poses a great challenge to data stream mining. Therefore, this paper proposes a dual detection mechanism to judge the drift of concepts, and on this basis, the integration classification of data stream is carried out. The system periodically detects data stream with the index of classification error and uses the features of the essential emerging pattern (eEP) with high discrimination to help build the integrated classifiers to solve the classification mining problems in the dynamic data stream environment. Experiments show that the proposed algorithm can obtain better classification results under the premise of effectively coping with the change of concepts.
In heterogeneous wireless sensor networks (HWSN), sensor nodes may fail due to running out of battery power or sudden damage. This causes HWSN being partitioned to a number of separate networks. ...Relay node placement is to add new relay nodes to partitioned HWSN such that the network recovers to wireless communication. Energy efficient routing in HWSN is useful for prolonging network lifetime and energy conservation. This paper attempts to solve relay node placement and energy efficient routing problems for HWSN. Both problems have seldom been studied together in the literature. This paper first constructs a mathematical model for both problems. For relay node placement problem, it is assumed that HWSN contains unreachable area, where sensor nodes could not be placed. For energy efficient routing, it is transformed to path length of wireless communication. As the problem is non-deterministic polynomial (NP) hard, a heuristic method called whale optimizer is used. The paper studies the effect of whale optimizer method with three adaptive schemes. Numerical simulations are done to test the proposed method for HWSN. The analysis and discussion show that the proposed method is useful to address NP hard relay node placement and energy saving problems for HWSN.
Precipitation in the Tianshan Mts is one of the main sources of subsurface and surface water in arid Xinjiang, China. Precipitation on the northern slope is significantly larger than that on the ...southern slope in the Tianshan Mts (i.e., annual average precipitation from 1951 to 2017 was 143 and 75 mm on the northern and southern slopes, respectively). The spatial distribution characteristics of precipitation largely influence the regional ecological environment and sustainable economic development. For better understanding the spatial difference of precipitation and the relations with climate modes in Tianshan Mts, this project selected Indian summer monsoon (ISM), El Niño–Southern Oscillation (ENSO), and Pacific Decadal Oscillation (PDO), which represent annual, interannual, and multidecadal climate modes, respectively, to investigate the relations between the climate modes and precipitation on the northern and southern slopes of Tianshan Mts. The linkages of the climate modes to precipitation of the northern and southern slopes were investigated by ensemble empirical mode decomposition (EEMD) and wavelet coherence analysis. The results show that these three climate modes are positively correlated with precipitation over entire Tianshan Mts. At annual scale, ISM strongly and almost equally affects precipitation on the northern and southern slopes. At interannual scales, ENSO mainly affects the precipitation of the northern slope, which is the major factor causing precipitation larger on the north than that on the south. At multidecadal scale, the effects of PDO on precipitation of northern and southern slopes are ambiguous.
The occurrence of potato common scab (PCS) in Yunnan Province is progressively increasing. To screen for high-efficiency control agents against PCS, this experiment used 70% Ambam, 20% zinc thiazole, ...60% Azoxystrobin, 90% Neophytamycin, 46.1% Copper hydroxide, 80% Ethylicin, and three Ambam-based compound formulations to conduct laboratory, greenhouse, and field control tests. In this study, 10 different species of
Streptomyces
(
S. turgidiscasies, S. scabies, S. enissocaesillies, S. luridiscaliei, S. caviscabies, S. anulatus, S. aureofaciens, S. acidiscabies, S. europaeicabiei
, and
S. griseus
) were used to screen the bactericides described above in the laboratory, and the results show that the anti-bacterial effects of different pesticides differ significantly. In Kirby-Bauer test, the inhibition zone diameter of Ambam is the biggest, and average diameter is 74.3 cm. The second largest diameter is three compounded formulations containing Ambam, while Kocide 3000 showed an average diameter is 38 mm. Kocide 3000, Ambam alone, and the three compounded.
In this paper, the entire network model is a hybrid wireless network model in which each base station is connected to each other via a wired link. On this basis, we place a large number of antennas ...(massive MIMO) at each base station to serve a single terminal in the downlink scenario, and we research the outage capacity and ergodic capacity in this scenario. The result of this paper is that the expressions for ergodic throughput capacity, outage probability, and outage throughput capacity have been derived under the favorable propagation condition. Through simulation, we can see the trend of outage throughput capacity and ergodic throughput capacity.
The collaborative relay network plays an important role in a smart grid application thanks to its high efficiency. However, energy and bandwidth management need to be further improved to extend ...network life cycle and reduce potential network segmentation. Aiming to balance the network energy consumption, this paper proposes an adaptive relay node selection algorithm based on the opportunity (OAR). In OAR, the potential relay nodes are chosen to act as candidates based on bit error rate (BER) estimation, and then, the relay is adaptively and opportunistically determined for packet forwarding. Residual energy is considered to avoid fast energy exhaustion for some certain nodes. The simulation results show that the proposed OAR algorithm improves the network performance by deferring the earliest death time of the nodes and extending the network life cycle.
Hyperspectral transmission imaging may provide a means for rapid screening of breast tumors, but tissue has a strong nature of scattering, thus causing a great difficulty in identifying ...heterogeneity. In this paper, a combination of frame accumulation and deep learning was proposed to detect heterogeneity, and we designed the simulation experiment of collecting phantom images. On the basis of frame accumulation preprocessing, the heterogeneous detection is performed on multispectral images by using faster regions with convolutional neural networks (R-CNN) features and a single shot multibox detector (SSD), two typical detection frameworks of deep learning. The results show that the mean average precision (mAP) of faster R-CNN and SSD reach 90.8% and 95.1%, respectively, when three classes (including background) are detected with the help of the dataset provided in this paper, and the mAP of two frameworks both reach 99.9% when two classes (including background) are detected. The detection efficiency of the SSD is higher than faster, SSD's detection speed can reach 50 fps, and the detection accuracy of the images after frame accumulation preprocessing is higher than that without frame accumulation processing. In summary, we validate the possibility of employing faster R-CNN and SSD to detect heterogeneity in multispectral images based on frame accumulation that improves image grayscale resolution, and it has a certain degree of reference significance for the application of deep learning in multispectral image detection.
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