Separation Scheme Research Articles

A Novel Real-Time Echo Separation Processing Architecture for Space–Time Waveform-Encoding SAR Based on Elevation Digital Beamforming

Space–time waveform-encoding (STWE) SAR can receive echoes from multiple sub-swaths simultaneously with a single receive window. The echoes overlap each other in the time domain. To separate the echoes from different directions, traditional schemes adapt single-null steering techniques for digital receive beam patterns. However, the problems of spaceborne DBF-SAR, in practice, such as null extension loss, terrain undulation, elevation angle of arrival extension, and spaceborne antenna beam control, make the conventional scheme unable to effectively separate the echoes from different sub-swaths, which overlap each other in the time domain.A novel multi-null constrained echo separation scheme is proposed to overcome the shortcomings of the conventional scheme. The proposed algorithm can flexibly adjust the width of the notch to track the time-varying pulse extension angle with less resource consumption. Moreover, the hardware implementation details of the corresponding real-time processing architecture are discussed. The two-dimensional simulation results indicate that the proposed scheme can effectively improve the performance of echo separation. The effectiveness of the proposed method is verified by raw data processing instance of an X-band 16-channel DBF-SAR airborne system.

Optimization of Two- and Three-Cascade Schemes for Efficient Separation of Stable Isotopes

Optimization of Two- and Three-Cascade Schemes for Efficient Separation of Stable Isotopes

Benchmark relativistic delta-coupled-cluster calculations of K-edge core-ionization energies of third-row elements.

A benchmark computational study of K-edge core-ionization energies of third-row elements using relativistic delta-coupled-cluster (ΔCC) methods and a revised core-valence separation (CVS) scheme is reported. High-level relativistic (HLR) corrections beyond the spin-free exact two-component theory in its one-electron variant (SFX2C-1e), including the contributions from two-electron picture-change effects, spin-orbit coupling, the Breit term, and quantum electrodynamics effects, have been taken into account and demonstrated to play an important role. Relativistic ΔCC calculations are shown to provide accurate results for core-ionization energies of third-row elements. The SFX2C-1e-CVS-ΔCC results augmented with HLR corrections show a maximum deviation of less than 0.5 eV with respect to experimental values.

Weighing Externalities of Economic Recovery Projects: An Alternative to Green Taxonomies that is Fairer and more Realistic

Natural and man-made crises and disasters often cause untold destruction, but also provide multiple opportunities for economic redevelopment post the crisis. Like other crises the COVID-19 pandemic has spurred public and private entities to become engaged in significant redevelopment efforts. Policymakers in some countries view these efforts as an opening for not only including other issues such as deficits in infrastructure and the social systems, but also for redefining their political priorities towards a “green economy”. While pursuing various policy objectives at the same time is a prudent undertaking, it seems rather questionable that politicians, under the pressure of ecological activism, would evaluate all crisis policy measures by their effect on environmental outcomes. We are seeing this in the European Union (EU) as it is about to couple its Recovery and Resilience Facility (financed through the “Next Generation EU Recovery Fund”) with its Green Deal. In the U.S., so far, the Build Back Better package and the American Rescue Plan seem to seek separate evaluation schemes for their different policy fields. The aim of this paper is to evaluate the wide-ranging opinions that exist on the intention to make recovery support contingent on ecological effects: For example, there is the classic Tinbergen Rule which states that for each policy target there must be at least one policy tool; thus, if there are fewer tools than targets, then some policy goals will not ultimately be achieved. Likewise, long-term climate change mitigation can only be achieved with long-term policies that consider and weigh out all externalities. Moreover, embarking on long term recovery plans cannot solely be formulated and implemented on ex-ante definitions of ecological impacts. The paper raises the question whether requesting ecological effects from all recovery programs is just and fair. It contrasts the various options of coupling recovery efforts and climate mitigation with state-of-the-art approaches of valuating multiple externalities: weighing the diverse externalities of policy projects can determine which policy tools to choose. It also demonstrates the downside of a policy that are solely focuses on granting financial support, if not, a project can effectively meet a pre-specified ecological and energy goal as set up by the EU and which ranks recovery projects according to their arbitrary effect on climate change. A wider scope of decision criteria will produce more effective ways to “build back better”.

Continuous Health Monitoring of Rolling Element Bearing Based on Nonlinear Oscillatory Sample Entropy

As a nonlinear measure, sample entropy (SE) can be considered as a suitable parameter for characterizing rolling element bearing health status by measuring complexity of vibration signals. However, in continuous monitoring scenario under noisy condition, all components of a multicomponent bearing signal are not equally sensitive towards change of SE value. As a consequence, a direct application of SE results into inefficient early fault warning and inability to differentiate among different fault types. To deal with this problem, instead of direct utilization of a whole vibration signal, its principal component (PC) sensitive to SE calculation is separated with the help of continuously adjustable parameterized tunable Q factor wavelet transform (TQWT). Since, TQWT uses an oscillation-based bearing PC separation scheme for SE calculation, the newly proposed measure is termed as oscillatory sample entropy (OSE). Due to the biasness of SE algorithm towards bearing PC, proposed OSE can anticipate theoretical concept of complexity change more efficiently with the change of bearing health. Two experimental case studies have shown that proposed OSE can not only overcome the limitations of SE algorithm also demonstrate superiority over approximate entropy (AE) and fuzzy entropy (FE) for continuous monitoring of bearing health.

Sparsity-Enhanced Convolutional Decomposition: A Novel Tensor-Based Paradigm for Blind Hyperspectral Unmixing

Blind hyperspectral unmixing (HU) has long been recognized as a crucial component in analyzing the hyperspectral imagery (HSI) collected by airborne and spaceborne sensors. Due to the highly ill-posed problems of such a blind source separation scheme and the effects of spectral variability in hyperspectral imaging, the ability to accurately and effectively unmixing the complex HSI still remains limited. To this end, this article presents a novel blind HU model, called sparsity-enhanced convolutional decomposition (SeCoDe), by jointly capturing spatial–spectral information of HSI in a tensor-based fashion. SeCoDe benefits from two perspectives. On the one hand, the convolutional operation is employed in SeCoDe to locally model the spatial relation between the targeted pixel and its neighbors, which can be well explained by spectral bundles that are capable of addressing spectral variabilities effectively. It maintains, on the other hand, physically continuous spectral components by decomposing the HSI along with the spectral domain. With sparsity-enhanced regularization, an alternative optimization strategy with alternating direction method of multipliers (ADMM)-based optimization algorithm is devised for efficient model inference. Extensive experiments conducted on three different data sets demonstrate the superiority of the proposed SeCoDe compared to previous state-of-the-art methods. We will also release the code at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/danfenghong/IEEE_TGRS_SeCoDe</uri> to encourage the reproduction of the given results.

Tandem-column extraction chromatography for Nd separation: minimizing mass-independent isotope fractionation for ultrahigh-precision Nd isotope-ratio analysis

A new rapid and effective Nd separation scheme for 142Nd/144Nd isotope ratio measurement is shown to have no detectable mass-independent isotope fractionation.

A Two-Stage Echo Separation Scheme for Spaceborne MIMO-HWRS SAR System

Multiple-input and multiple-output synthetic aperture radar (MIMO SAR) is a very potential technique for high-resolution and wide-width (HRWS) imaging due to the fact that it can provide more degrees of freedom. In this paper, an innovative MIMO-HRWS SAR imaging system is introduced with segmented phase coding (SPC) waveforms. However, it is well known that the echo separation issue is the most technical challenge for MIMO SAR. It has shown that the separation of orthogonal echoes from cross-correlation interference can be achieved by scan-on-receive (SCORE). However, this method often requires large computing resources on board, especially for null-steering process. For this, we propose a two-stage spaceborne-ground echo separation scheme. This scheme is mainly divided into two-steps: the first step is a real-time SCORE-beamforming process on board to reduce the downlink data volume, and the second step is a bandpass-null steering process to suppress the interfering echoes on the ground. Thus, this scheme allows for the low computing resources on board and sufficient suppression of the interference simultaneously. Following this scheme, the MIMO-HRWS SAR system enables its number of equivalent phase centers nearly double that of the azimuth multichannel SAR system, thus higher-resolution and wider-swath imaging. Finally, detailed simulation experiments for the MIMO-HRWS SAR imaging system are performed to verify the practicability and feasibility of the proposed scheme.

Customer Data Processing in Internet of Things Environments Using RFM Analysis and K-means Clustering

Businesses, shops, banks, and other types of organizations all engage in cutthroat competition today. The retrieval techniques are responsible for arranging, processing, and listing the documents in the corpus in response to the user query. The strategies are distinct from one another in any of the processes stated above. As a result, the body of published work is crammed full of different retrieval theories and strategies. It is possible to combine the advantageous aspects of several different strategies to improve the retrieval systems' overall performance. Once again, the success of the merging process is dependent on the careful selection of the separate schemes that will be merged together. The selection process is carried out using optimization-seeking tools. The Genetic Algorithm is going to be used for this job. Using GA as the instrument and with the intention of evaluating both the even and the odd point crossover's effects, The odd and even point crossover is primarily employed as an exploratory tool, and its influence on the Internet of Things is evaluated throughout the information retrieval process. The enormous combination that results from the fusion function retrieval strategies and their weights may be understood as follows: The investigation is the only thing that can help us find the best answer out of all of these possible permutations. As a method of investigation, we made use of both odd and even point crossing. This exploration tool has a lack of convergence, which is a setback. It is possible to get a higher convergence rate by combining the genetic algorithm with tabu search, which is the best local search. In a scenario like this one, customer segmentation may be helpful in bringing in new customers while also helping to keep the ones you already have. An effective customer segmentation strategy for a business splits consumers into groups based on the RFM (Recency, Frequency, and Monitor) values of the Monitors. These groups have behavior in common. This will be of use to us in determining the possible customers for the firm. Following the completion of an RFM analysis, we use a conventional k-means method in order to extend the scope of the research to include clusters. Maintaining positive relationships with customers makes it much easier to market effectively to certain demographics of consumers, which in turn helps bolster a company's competitive position.

First Demonstration of Echo Separation for Orthogonal Waveform Encoding MIMO-SAR Based on Airborne Experiments

Multiple-input&#x2013;multiple-output synthetic aperture radar (MIMO-SAR) has extensive application prospects, mainly including the acquisition of multidimensional scattering information, high-resolution and wide-width (HRWS) imaging, and moving target indication (MTI). Its echo separation is the most technical challenge, and so far, the confirmation for orthogonal waveform encoding MIMO-SAR by airborne experiments has not been reported in any literature. Here, an echo separation experiment based on the segmented phase code (SPC) waveforms and an airborne digital beamforming SAR (DBF-SAR) system is demonstrated for the first time. In the experiment, the SPC waveforms are cyclically transmitted within the adjacent pulse repetition intervals (PRIs) to simulate multiple transmitters, and the scattered echoes are received by the 16-channel antennas in elevation at the same time. In the postprocessing, the echo signals of continuous PRIs are added to obtain the mixed echoes, and a detailed echo separation method is adopted. In the method, the mixed echo signals from close arrival angles and far arrival angles are separated by the time shift and weighting, and by the bandpass filtering and DBF technique, respectively. Through the presented method, the mixed echoes of dual-transmit and 16-receive (2T16R) SAR imaging mode are separated and imaged successfully. The experimental results not only validate the echo separation scheme but also indicate that it is very promising in future MIMO-SAR missions.

Separable Synchronous Multi-Innovation Gradient-Based Iterative Signal Modeling From On-Line Measurements

This article is aimed to study the modeling problems of combinational signals or periodic signals. To overcome the computation complexity of modeling the signals with plenty of characteristic parameters, a parameter separation scheme is developed based on the different characteristic of the signals to be modeled. For the purpose of achieving high-accuracy performance and reducing complexity, two multi-innovation gradient-based iterative (MIGI) subalgorithms are presented by means of gradient search. In terms of the phenomenon that the coupling parameters lead to the inability of algorithms, a separable synchronous (SS) interactive estimation method is proposed to eliminate the coupling parameters and perform the signal modeling algorithm in accordance with the hierarchical principle. By means of simulation experiments, the proposed SS iterative signal modeling algorithm based on the moving batch data is used for estimating a power signal with three sine waves and a periodic square wave signal. The results demonstrate the effectiveness of the proposed method for modeling the combinational signals with multiple frequencies and other periodic signals. Since the proposed method combines real-time data sampling and iterative estimation, it can be used for on-line identification.

Study on Probabilistic Risk Assessment Model for Crossing Situation in Sunda Strait

Sunda Strait is a busy channel where cargo vessels could probably have a crossing situation with roro ferries. Due to a very limited record of the actual crossing collisions in Sunda Strait, this study performs a Probabilistic Risk Assessment (PRA) of near miss crossing situations in Sunda Strait due to the Traffic Separation Scheme (TSS) that has been set since July 1st, 2020. The analysis is based on the Automatic Identification System (AIS) data during three time-intervals (TI), the first two TIs represented the condition before the TSS came into force, while the last TI was taken after the TSS has been set. The traffic in Sunda Strait was categorized to eight vessel courses, two conditions and seven crossing zones. We proposed a new perspective for the evaluating the TSS by looking at the crossing situation with three different bases, namely crossing zone basis, course basis, and vessel type basis. The probability of a crossing situation was calculated based on the hour basis for each time interval. The UK HSE standard for individual risk is utilized and it is found that the TSS effectively reduced the frequency level of crossing situation from unacceptable to ALARP in CZ 1, 2, and 4. While in CZ 3, the frequency is decreased dramatically from unacceptable to acceptable level.

Maritime Traffic Route Detection Framework Based on Statistical Density Analysis From AIS Data Using a Clustering Algorithm

Maritime traffic routes by ships navigation vary according to country and geographic characteristics, and they differ according to the characteristics of the ships. In ocean areas adjacent to coasts, regulated routes are present, e.g., traffic separation scheme for ships entering and leaving; however, most ocean areas do not have such routes. Maritime traffic route research has been conducted based on computer engineering to create routes; however, ship characteristics were not considered. Thus, this article proposes a framework to generate maritime traffic routes using statistical density analysis. Here, automatic identification system (AIS) data are used to derive quantitative traffic routes. Preprocessing is applied to the AIS data, and a similar ship trajectory pattern is decomposed into a matrix based on the Hausdorff&#x2013;distance algorithm and then stored in a database. A similar pattern makes the AIS trajectory simple using the Douglas&#x2013;Peucker algorithm. In addition, density-based spatial clustering of applications with noise (DBSCAN) is performed to identify the waypoints of vessels then create routes by connecting waypoints. The width of maritime routes created based on a similar ship trajectory is subjected to kernel density estimation analysis (KDE). Then, waypoints evaluation of the main route is performed from the results of KDE 75&#x0025; and 90&#x0025; considering the statistical in the total maritime traffic, and the results applied to the targeted ocean area are compared. Finally, the result of KDE 90&#x0025; of maritime traffic with framework analyzed the safety route, which can be a basis for developing routes for maritime autonomous surface ships.

Electrophoretic determination of carboxylic acids in blood serum with intracapillary concentration

Electrophoretic separation and on-line concentration of short-chain fatty acids (SCFAs) in human blood serum of the patients with the inflammatory bowel disease is described in the current investigation. SCFAs are end products of carbohydrate fermentation, which are indigestible in the intestine. The highest concentrations of SCFAs are in the proximal colon, where they are absorbed by the epithelial cells of the colon (colonocytes) and then enter the tissues and blood. The changes in their serum content can indicate the metabolism disorders and inflammatory bowel diseases. The low sensitivity of capillary electrophoresis requires application of on-line concentration in order to implement this method for the detection of low concentrations of SCFAs in biological fluids. Moreover, for the salt-matrix samples, an application of common concentration techniques based on the differences in conductivity of sample matrix and background electrolyte is limited. Therefore, the development of fast, efficient and highly sensitive approaches for the determination of SCFAs in blood serum is an important task. In the current work, the improvement of the sensitivity of SFCAs has been achieved by the application of a water plug, which was proposed to be injected directly before the sample in order to form a low conductivity area for the acceleration and concentration of the analytes. The proposed preconcentration and electrophoretic separation scheme provided decreased detection limits of SCFAs (~ 50 - 70 ng/mL) due to 30 times concentration of analytes as well as fast analytes’ determination (15 min).

Recent progress on porous MOFs for process-efficient hydrocarbon separation, luminescent sensing, and information encryption.

Metal-organic frameworks (MOFs), as an emerging class of porous materials, excel in designability, regulatability, and modifiability in terms of their composition, topology, pore size, and surface chemistry, thus affording a huge potential for addressing environment and energy-related challenges. In particular, MOFs can be applied as porous adsorbents for the purification of industrially important hydrocarbons through certain process-efficient separation schemes based on selectivity-reversed adsorption and multicomponent separation. Moreover, the vast combination possibilities and controllable and engineerable luminescent units of MOFs make them a versatile platform to develop functionally tailored materials for luminescent sensing and optical data encryption. In this feature article, we summarize the recent progress in the use of porous MOFs for the separation and purification of acetylene (C2H2) and ethylene (C2H4) based on selectivity-reversed adsorption and multicomponent separation strategies. Moreover, we highlight the advances over the past three years in the field of MOF-based luminescent materials for thermometry, turn-on sensing, and information encryption.

ESTABLISHMENT OF LOMBOK STRAIT TRAFFIC SEPARATION SCHEME AND ITS IMPACTS ON MARITIME SECURITY

&lt;div&gt;&lt;p class="Els-history-head"&gt;The Lombok Strait, which is part of the Indonesian Archipelagic Sea Lane II, has been established as a Traffic Separation Scheme, based on several considerations such as safety of navigation and preservation of the natural environment. This study aimed to explore the process of establishing the Lombok Strait Traffic Separation Scheme and to analyze its impacts on Indonesia's maritime security in the area. It was a qualitative study, using a case study approach. The data obtained from the literature study came from several scientific articles and government documents, interviews with several informants, and direct observations of the object under study. This study found that there were direct impacts of the establishment on the government institutions related to the management and execution of the Traffic Separation Scheme, on the adequacy of infrastructure related to the supervision and control of the Traffic Separation Scheme, and in the long term, there will be various potential impacts in form of several threats to Indonesia's maritime security, such as piracy, armed robbery, sea accidents, smuggling, pollution, and terrorism.&lt;/p&gt;&lt;/div&gt;

Increasing wear and corrosion resistance of steel products by combined laser thermomechanical treatment

A technique is presented for hardening metal products, in particular, the main tools (hammers) and cases of core drilling bits made of steel 30HGSA, using thermomechanical surface treatment according to a separate scheme. The method of combined laser thermomechanical hardening used in the study consists in the use of shot peening followed by laser heat treatment. Its use makes it possible to increase the operational properties of steel products, in particular, their wear and corrosion resistance. Based on the results of theoretical and experimental studies, the paper substantiates the features of dynamic surface plastic deformation for the analysis of impact during shot peening. The advantages of using laser hardening without surface melting are presented. Experimental research methods are proposed for determining the structural-phase composition, structure of the surface layer, hardness and microhardness of the hardened zones of steel 30HGSA. The range of rational modes of impact shot peening and thermal laser treatment has been determined. A device for testing samples for wear resistance has been developed. Methods of testing for wear and corrosion resistance of the surface of samples are proposed for assessing the tribological properties and contact interaction of materials under quasi-static and dynamic loading conditions. It is concluded that rational technological modes of hardening tools made of steel 30HGSA using combined laser thermomechanical treatment allow increasing the depth of the hardened layer by ~1.5 times compared to laser heat treatment. In addition, they provide the microhardness of the surface layer of ~5400 MPa, which is ~2.5 times higher than the microhardness of the base material

Contamination of the Dzheltulak-1 river basin under alluvial gold mining (the Amur region)

The purpose of the introduced research is to study the environmental impact of placer gold mining. The object of the study is natural and natural-man-made geosystems of the Dzheltulak-1 river located in the Amur region. The content of the main cations and microelements in water samples was determined by atomic emission and mass spectral methods. The content of micro- and rock-forming elements in bottom sediments and soils was determined by X-ray fluorescence using XRF-1800 X-ray spectrometer (Shimadzu, Japan). The results of the conducted studies indicate that the contents of iron, manganese, copper, aluminum, vanadium, molybdenum, mercury and ammonium ions exceed commercial fishery standards in a significant part of the surface water samples. It is found out that settlement ponds negatively affect the water quality in the river Dzheltulak-1 downstream due to the dam drainage. The highest concentrations of dissolved forms of mercury were noted in the water of the settlement ponds. The gross content of arsenic in the samples of bottom sediments and soils exceeds sanitary and hygienic standards by 2.7–14.5 times. The distributions of mercury as the most dangerous pollutant among the biogenic components of geochemical landscape were worked out in detail. Mercury contamination of soils was classified according to the forms of mercury occurrence: free, physically sorbed, chemisorbed, sulfide and isomorphic. It has been shown that the free form is characteristic of fresh mercury contamination due to the use of prohibited technological schemes for gold-bearing sands separation by the amalgamation method.

Development of information web-service for providing services

Problem. Today the most relevant topic is the creation of websites. This is because almost any field of activity, whether related to goods or services, requires information-based promotion. The main purpose of the site is to tell the users about the company's data. There are different ways of informing on the Internet, but usually they all come down to one thing – a website. A website is a collection of electronic documents combined into a single address. With the growth of technology, websites are becoming not just a collection of documents, but also a presentation of a number of technologies that are used both to attract attention and to add various features, not only exciting but also convenient, that allow the user to stay on the site. That is why the article discusses the features and methods of developing a web service based on angular technology for ordering a tow truck service centering on the capabilities of modern browsers.&#x0D; Goal. This article examines the process of creating a web service based on Angular technology to order a tow truck service centering on the capabilities of modern browsers. The problems of work with services are considered and the necessity of creation of this service is substantiated. Methodology. An analysis of technologies and systems for the creation of this software, taking into account the support of work on mobile devices is made. The scheme of functioning of the service is developed and its structure is considered. The structure of the service software is developed and substantiated, separate schemes for each of the submitted pages are considered. Practical meaning. This service is designed to provide tow truck services, thanks to which every driver can easily order a tow truck at any time, which will reduce the time to find a tow truck. The necessary software was installed on the computer during the development of the information service. In the process of long-term software development, more and more dangerous factors appear on the PC, which affect the health and damage of the most vulnerable systems of the body. In an emergency, the computer must be turned off immediately.

Attenuation compensation for wavefield‐separation‐based least‐squares reverse time migration in viscoelastic media

ABSTRACTElastic least‐squares reverse time migration can image the multicomponent seismic recordings. However, on the one hand, without considering the intrinsic attenuation of the subsurface, it may produce blurred reflectivity images with incorrect positions of reflectors for seismic recordings with strong attenuation. On the other hand, the crosstalk artefacts created by the different wave modes may severely degrade the imaging quality. To alleviate these crosstalk artefacts and compensate for the attenuation effects, we have developed a time‐domain wavefield‐separation‐based least‐squares reverse time migration approach in viscoelastic media, which utilizes the viscoelastic wave equation on the basis of the standard linear solid model to simulate intrinsic subsurface attenuation. The key point of the proposed approach is that we utilize the separated gradient contribution of PP‐ and PS‐wave modes based on the wavefield separation technique in viscoelastic media to construct the P‐wave and S‐wave velocity images, respectively. Unlike the conventional wavefield‐separation‐based least‐squares reverse time migration approach, which generally uses the new stress–velocity equations to formulate, our proposed wavefield separation scheme fully depends on the conventional viscoelastic wave equation and its adjoint wave equation. By introducing the pure P‐wave stress in the forward and adjoint wavefields, the coupled wavefields can be well decomposed, which requires much less computational costs than the wavenumber‐domain wavefield separation scheme. Numerical examples using the layered and Marmousi‐2 models have shown that the proposed approach can improve the migration image quality under geological conditions with strong attenuation where elastic least‐squares reverse time migration may produce blurred and unfocused events. Meanwhile, the proposed least‐squares reverse time migration approach with the wavefield separation scheme has a better convergence rate and produces fewer crosstalk artefacts than that without the wavefield separation scheme.