scholarly journals Clutter cancellation in passive radar using batch-based CLEAN technique

Author(s):  
Xia Bai ◽  
Jiatong Han ◽  
Juan Zhao ◽  
Yuan Feng ◽  
Ran Tao

AbstractPassive radar (PR) systems need to detect the presence of a target response, which is many orders of magnitude weaker than the clutter (direct signal and multipath). Indeed, the clutter cancellation is a key stage within a PR processing scheme. One of the most effective techniques in this field is using the CLEAN approach. In this paper, the batch-based CLEAN technique based on GMP and FFT has been proposed, which can speed up the computational processing and have better cancellation gain. Furthermore, segmenting operation can be applied to the signal obtained over long time. It is helpful to enhance temporal or spatial efficiency and overcome effect of time-varying clutter. Experiment results with simulated and real passive radar data verify the effectiveness of the proposed algorithm.

Author(s):  
Arnaud Dufays ◽  
Elysee Aristide Houndetoungan ◽  
Alain Coën

Abstract Change-point (CP) processes are one flexible approach to model long time series. We propose a method to uncover which model parameters truly vary when a CP is detected. Given a set of breakpoints, we use a penalized likelihood approach to select the best set of parameters that changes over time and we prove that the penalty function leads to a consistent selection of the true model. Estimation is carried out via the deterministic annealing expectation-maximization algorithm. Our method accounts for model selection uncertainty and associates a probability to all the possible time-varying parameter specifications. Monte Carlo simulations highlight that the method works well for many time series models including heteroskedastic processes. For a sample of fourteen hedge fund (HF) strategies, using an asset-based style pricing model, we shed light on the promising ability of our method to detect the time-varying dynamics of risk exposures as well as to forecast HF returns.


RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22788-22796 ◽  
Author(s):  
Huizhi Hu ◽  
Junguo He ◽  
Huarong Yu ◽  
Jian Liu ◽  
Jie Zhang

The start-up period of biofilm reactors often takes a long time to obtain a mature and stable biofilm, especially at low temperature.


2015 ◽  
Vol 1 (1) ◽  
pp. 26-33
Author(s):  
Grifito yuan Maulidina

The development of online payment systems such as the online payment point system has greatly assisted the public in processing monthly transactions such as water bills. However, in its application, this system still uses large devices such as computers and inkjet printers so that the operation takes a long time and is less efficient. Therefore, in this study, a mobile application is designed to replace the role of computers in making water bill payment transactions in the online payment point system (SOPP) of PDAM Malang Regency. The application that is connected to a database server via the internet is also integrated with a compact wireless thermal printer that can be carried anywhere and does not require ink refills so that it can speed up the transaction process and be more efficient in time, paper and space. The research method used was experimental and survey methods. The experimental method is used to test the running of the application, test the application's compatibility with the device and measure the time it takes for the application to exchange data. The survey method is used to test user satisfaction with the application.


Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6523
Author(s):  
Pieter Van Van Molle ◽  
Cedric De De Boom ◽  
Tim Verbelen ◽  
Bert Vankeirsbilck ◽  
Jonas De De Vylder ◽  
...  

Deep neural networks have achieved state-of-the-art performance in image classification. Due to this success, deep learning is now also being applied to other data modalities such as multispectral images, lidar and radar data. However, successfully training a deep neural network requires a large reddataset. Therefore, transitioning to a new sensor modality (e.g., from regular camera images to multispectral camera images) might result in a drop in performance, due to the limited availability of data in the new modality. This might hinder the adoption rate and time to market for new sensor technologies. In this paper, we present an approach to leverage the knowledge of a teacher network, that was trained using the original data modality, to improve the performance of a student network on a new data modality: a technique known in literature as knowledge distillation. By applying knowledge distillation to the problem of sensor transition, we can greatly speed up this process. We validate this approach using a multimodal version of the MNIST dataset. Especially when little data is available in the new modality (i.e., 10 images), training with additional teacher supervision results in increased performance, with the student network scoring a test set accuracy of 0.77, compared to an accuracy of 0.37 for the baseline. We also explore two extensions to the default method of knowledge distillation, which we evaluate on a multimodal version of the CIFAR-10 dataset: an annealing scheme for the hyperparameter α and selective knowledge distillation. Of these two, the first yields the best results. Choosing the optimal annealing scheme results in an increase in test set accuracy of 6%. Finally, we apply our method to the real-world use case of skin lesion classification.


2021 ◽  
Vol 447 (3) ◽  
pp. 13-18
Author(s):  
Z.А. Anarbekova ◽  
G.I. Baigazieva

Wine is a product of biochemical transformations, compounds present in grape juice, by controlled alcoholic fermentation, that is, effervescence. Grape and yeast enzymes play a key role in the processing of grapes and the preparation of wine, influencing all biotechnological processes of winemaking. Adding liquid or dry active yeast to the wort allows better control of the fermentation process. Under the influence of these yeasts, sugar is converted mainly into alcohol or carbon dioxide, but the yeast itself during fermentation produces many molecules (higher alcohols, esters) that affect the aroma and taste of wine. These transformations take about two weeks and lead to a significant increase in temperature, which must be regulated, not allowing it to rise above 18-20°C: otherwise, some of the aromatic substances may evaporate and the fermentation process itself will stop. The amount of yeast that determines the correct and complete fermentation depends both on the quality of the wort itself, and on the more or less prolonged access of air, the ambient temperature. The air, or rather the oxygen of the air, has a beneficial effect on fermentation as long as there are still many nutrients (sugars) in the wort; as the latter are consumed, extremely small yeast cells are formed, which persist for a long time in the form of turbidity. The rapid course of fermentation can be greatly facilitated by the periodic stirring of yeast, which, settling to the bottom, lose direct contact with nutrients — the lower layers almost do not function. You can mix the wort mechanically or by adding healthy whole grapes to it; in this case, the wort is constantly and automatically mixed: the berries, rising up in the fermenting liquid, carry the yeast with them. In order to speed up the fermentation, the wort is sometimes ventilated, that is, air is introduced into it, by mixing. This article shows the influence of the yeast race on the fermentation dynamics of white grape must, the composition of organic acids and aroma-forming components. The races that ensure the production of highquality wine materials are identified.


2021 ◽  
Author(s):  
F. Ramirez-Rasgado ◽  
M. Farza ◽  
M. M'Saad ◽  
O. Hernandez-Gonzalez ◽  
C.M. Astorga-Zaragoza

Author(s):  
Widya Sari ◽  
I Wayan Budiarsa Suyasa ◽  
I.G.B Sila Dharma

ABSTRACT        The production of pig manure waste potentially pollutes the soil, water and air. One of the most effective processing a waste treatments is through composting. The composting process takes a long time if not assisted by the activator as decomposers of organic materials in order to accelerate the composting process. Activators such as local microorganism (MOL) contain macro nutrients, micro and active microorganism that potentially decomposed organic materials, growth stimulants and pest/disease control agents such as to help speed up the composting process. This study aims to determine the C/N ratio of optimal raw materials for composting of pig manure and vegetable waste, determining the effect of adding local microorganism (MOL) to the length of time of composting and determining the effectiveness of business from composting of pig manure and vegetable waste based on the calculation of B/C ratio.        This research uses quantitative approach with experiment method. The first stage is the preparation of the raw material which is divided into three groups : composition 1 with 75% (pig manure) and 25% (vegetable waste), composition 2 with 50% (pig manure) and 50% (vegetable waste) and then composition 3 with 25% (pig manure) and 75% (vegetable waste). Furthermore, the best raw material composition was treated with variations of MOL addition of A (100 ml), B (300 ml), C (500 ml) and D (without MOL).        The results showed that the composition of the best raw material mixture was a mixture composition of 25% (pig manure) and 75% (vegetable waste) with a C/N ratio of 38.95. The effect of MOL addition indicates that the greater MOL volume the faster to composting process. The quality compost with addition of MOL has C/N ratio levels is (16,30), N-total (1,65%), P tersedia (8043,02 ppm), K tersedia (8857,40 ppm), Fe (1,87%), Mn (0,09%) Zn (480 ppm) in which that value meets the SNI 19-7030-2004. Based on analysis of B/C ratio obtained result of 1.04 where the value is approaching criteria B/C ratio more than 1.00 which means compost business feasible to be developed.   Keywords : Pig manure, MOL, time of composting, composter, B/C ratio


2013 ◽  
Vol 59 (217) ◽  
pp. 883-892 ◽  
Author(s):  
A.V. Sundal ◽  
A. Shepherd ◽  
M. van den Broeke ◽  
J. Van Angelen ◽  
N. Gourmelen ◽  
...  

AbstractShort-term ice-dynamical processes at Greenland’s Jakobshavn and Kangerdlugssuaq glaciers were studied using a 3 day time series of synthetic aperture radar data acquired during the 2011 European Remote-sensing Satellite-2 (ERS-2) 3 day repeat campaign together with modelled meteorological parameters. The time series spans the period March–July 2011 and captures the first ∼30% of the summer melting season. In both study areas, we observe velocity fluctuations at the lower ∼10 km of the glacier. At Jakobshavn Isbræ, where our dataset covers the first part of the seasonal calving-front retreat, we identify ten calving episodes, with a mean calving-front area loss of 1.29 ± 0.4 km2. Significant glacier speed-up was observed in the near-terminus area following all calving episodes. We identify changes in calving-front geometry as the dominant control on velocity fluctuations on both glaciers, apart from a <15% early-summer speed-up at Kangerdlugssuaq Glacier during a period of calving-front advance, which we attribute to enhanced surface melt-induced basal lubrication. Our 3 day velocity maps show new spatial characteristics of the ice melange flow variability in the Jakobshavn and Kangerdlugssuaq fjord systems, which are primarily controlled by calving-front dynamics and fjord geometry.


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