Numerical Mapping Research Articles

Speckle‐Free 3D Holography in the Wigner Domain

AbstractComputer‐generated hologram (CGH) provides an approach to modulate the 3D coherent wavefront and has been widely used in many optical applications. Over the past few decades, extensive efforts have been made to design optimization models for high‐quality reconstruction. However, the reconstruction quality is still limited due to the mismatch of the bandwidth between the reconstructed field of interest and the reconstructed complex amplitude field in 3D space. Here, an ideal numerical light field mapping physical model from the hologram plane to the 3D image plane for speckle‐free 3D holography in the Wigner domain is established. With the aid of the Wigner distribution function (WDF), which allows the analysis of a light field from not only the space domain but also the spatial frequency domain, the bandwidth properties of the reconstructed field in 3D space are analyzed, which provides a guideline for the sampling of the reconstructed field to efficiently describe the speckles and artifacts. Accordingly, a comprehensive CGH optimization method in the Wigner domain is proposed to constrain the reconstructed intensity fluctuations without errors and omissions for high‐quality reconstruction. As such, this method enables speckle‐free and artifact‐free reconstruction with a twice improvement in peak signal‐to‐noise ratio (PSNR) and a five times improvement in structural similarity index measure (SSIM) compared to conventional phase‐only holograms. The optical experimental results show that this method paves the road for the future implementation of speckle‐free color 3D holography harnessing the advanced integrated photonic devices, and also offers an efficient and practical route for various optical applications, such as 3D display, optical encryption, beam shaping, optical computing and so on.

Near Real-Time Flood Monitoring Using Multi-Sensor Optical Imagery and Machine Learning by GEE: An Automatic Feature-Based Multi-Class Classification Approach

Flooding is one of the most severe natural hazards, causing widespread environmental, economic, and social disruption. If not managed properly, it can lead to human losses, property damage, and the destruction of livelihoods. The ability to rapidly assess such damages is crucial for emergency management. Near Real-Time (NRT) spatial information on flood-affected areas, obtained via remote sensing, is essential for disaster response, relief, urban and industrial reconstruction, insurance services, and damage assessment. Numerous flood mapping methods have been proposed, each with distinct strengths and limitations. Among the most widely used are machine learning algorithms and spectral indices, though these methods often face challenges, particularly in threshold selection for spectral indices and the sampling process for supervised classification. This study aims to develop an NRT flood mapping approach using supervised classification based on spectral features. The method automatically generates training samples through masks derived from spectral indices. More specifically, this study uses FWEI, NDVI, NDBI, and BSI indices to extract training samples for water/flood, vegetation, built-up areas, and soil, respectively. The Otsu thresholding technique is applied to create the spectral masks. Land cover classification is then performed using the Random Forest algorithm with the automatically generated training samples. The final flood map is obtained by subtracting the pre-flood water class from the post-flood image. The proposed method is implemented using optical satellite images from Sentinel-2, Landsat-8, and Landsat-9. The proposed method’s accuracy is rigorously evaluated and compared with those obtained from spectral indices and machine learning techniques. The suggested approach achieves the highest overall accuracy (OA) of 90.57% and a Kappa Coefficient (KC) of 0.89, surpassing SVM (OA: 90.04%, KC: 0.88), Decision Trees (OA: 88.64%, KC: 0.87), and spectral indices like AWEI (OA: 84.12%, KC: 0.82), FWEI (OA: 88.23%, KC: 0.86), NDWI (OA: 85.78%, KC: 0.84), and MNDWI (OA: 87.67%, KC: 0.85). These results underscore the superior accuracy and effectiveness of the proposed approach for NRT flood detection and monitoring using multi-sensor optical imagery.

Estimating the Distance Between Map Points May Be Related to Forms of Representing the Map´s Scale.

The way a map scale is represented plays a key role in comprehending it. In this research, we examined the relationships between the form of representation of the map's scale (numerical scale, linear graphic scale and circular graphic scale), the user's gender, and the distance between two map objects on user estimates of the distance between two objects on the map (i.e., a 5, 10, 15 and 20-min walk). We gave 183 college students 84 maps of three types: 28 numerical scale, 28 linear graphic scale, and 28 circular graphic scale. Each map presented varied distances to be estimated. We assessed the participants' accurate hits, errors, and their hits minus errors in these distance estimations. Participants had both more hits and more errors on circular scale maps than on linear or numerical scale maps, and the distances between objects and gender also significantly related to the estimated e distance. Both the type of scale and the distance between objects influenced the number of hits minus the number of errors.

Aerodynamic reverse engineering design using fuzzy logic

Abstract The goal of this paper is to create a solid and efficient design method leveraging a fuzzy logic algorithm. This fuzzy logic system presents a non-analytical structure, facilitating the management of numerical mappings and data obtained by measurements and analytical relations, while also utilising the knowledge distributed in previous projects. Employing this information, the fuzzy logic algorithm can quickly generate an initial design, serving as a solid foundation for further optimisation. This first-glance solution can be leveraged to generate a few other designs in its neighbourhood that will then constitute the Fuzzy Logic Base of rules for further optimisation. The proposed method’s effectiveness and efficiency are demonstrated through the design of a nozzle for both subsonic and transonic flow conditions.

Maps of agrolandscape and ecological zoning of natural and natural-agricultural ecosystems of the Russian Federation

Agriculture has a large area of coverage and places the greatest burden on land, soil, water and biological resources in many countries of the world. Agricultural lands occupy huge areas in the world (4.8 billion hectares, or 37% of the land) and in Russia (221.9 million hectares, or 13% of the Russian Federation area). The agriculture best adapted to local conditions is the most beneficial one for people and nature. The main direction of agricultural adaptation is agrolandscape-ecological zoning. In order to provide information support for regionally, landscapeand ecologically differentiated agriculture and rational environmental management, an agrolandscape– ecological zoning of natural and natural-agricultural ecosystems was developed for the first time for all 11 natural-economic regions of Russia, namely, Northern, North-Western, Volga–Vyatka, Central, Central Black Earth, Volga, North Caucasus, Ural, West Siberian, East Siberian, and Far Eastern. The zoning was carried out using comparative geographical and agrolandscape-ecological methods, ecological-landscape and agroecological approaches. The contour and information basis for zoning is the map of Soil–Ecological zoning of the Russian Federation from the Faculty of Soil Science of Lomonosov Moscow State University. Maps of other types of zoning, numerous maps and atlases, statistical data, available literary and stock sources, ground-based and remote data were also used. Our sets of zoning materials included: a map, a map legend, 3 databases (land, forage lands, and negative processes), 2 classifications (forage lands, reindeer pastures, if any), articles, monographs, recommendations, and proposals for production. The maps have been compiled on a 1:2,500,000 scale on a modern, highly informative topographic cartographic basis for the map of Russian Federation. The maps show 6 types of boundaries, including 4 types of agrolandscape-ecological ones (taken from the Soil–Ecological Zoning map): 1) zones, 2) mountainous territories, 3) provinces, 4) districts and 2 types of administrative ones (available on the cartographic basis) of: 1) constituent entities of the Russian Federation, and 2) natural-economic regions.

Influence of Blowing Musical Instruments on Geometrical Face Changes: 3D Evaluation Study.

This study examined changes in facial geometry while playing wind instruments. Nine musicians participated (6 men, 3 women, mean age 52 years) in part 1 of the study, and 3 musicians participated (3 women, mean age 41 years) in part 2. In part 1, the high and low notes of each instrument were selected as test sounds. Facial geometry data were recorded using a 3D scanner. In part 2, facial geometry data were recorded using a 4D scanner while a melody was played. Data were superimposed and analyzed using 3D analysis software. Numerical values and color maps of deviations were obtained. The results of part 1 revealed that the median 3D deviation was 1.1 mm (range 0.42-1.45 mm), indicating that facial geometry while playing high and low notes was varied. The results of part 2 showed that the stable part was the frontal region and dorsal part of the nose. The approach used in this study has potential applications for evaluating facial geometry during musical instrument performances.

Ідентифікація координат імпульсних джерел забруднень стічних вод в кусково-однорідних середовищах числовими методами квазіконформних відображень

The process of filtration in a single-connected curvilinear domain bounded by streamlines and equipotential lines is considered, provided that the medium under study is piecewise homogeneous. It is assumed that certain unknown curves act as impulse sources of pollution. It is assumed that their propagation occurs only due to the convective component, without significantly affecting the filtration background. It is proposed to use the method of characteristics for solving the convection equation to identify the coordinates of pollution sources. In this case, quasipotentials at the fluid inlet and outlet at the boundary of the domain, coordinates of the points of pollution detection, and the time of its movement downstream can serve as a priori data. The general algorithm involves the adaptation of the numerical quasiconformal mapping method to build a hydrodynamic mesh, according to which the coordinates of pollution sources are identified. Numerical experiments were carried out and analysed. In particular, it is emphasised that with a sufficient mesh division, the maximum discrepancies between the a priori known data and the calculated data are small compared to the size of the studied domain. This indicates the effectiveness of the developed algorithm for identifying pollution sources in the case of a piecewise homogeneous environment. As an additional measure to reduce the magnitude of the uncertainties, it is proposed to use more accurate approximation schemes for specific expressions. On the other hand, there is an increase in computational complexity compared to the case of a continuous setting of the filtration coefficient. Given the relatively high accuracy of the calculations, it seems advisable to further develop an described approach to larger-scale in comparison with point sources of pollution and to spatial case. Taking into account the sensitivity of the solutions to the discontinuity of the filtration coefficient values, it is also worthwhile to introduce additional conditions at the contact of homogeneous media in the future.

Electrodeposited Pt nanoparticles loaded on support composites of metal-organic frameworks and carbon quantum dots for the enhancement of alcohol electrooxidation

Metal-organic frameworks comprising divalent metal (M)-linked 4,4′-bipyridine (bpy), {[CuII4(bpy)3(OH)2(mal)3]·4H2O}n(Cubpy) and Ni2(bpy)3(NO3)4(H2O)4(Nibpy) were modified with carbon quantum dots (Mbpy/CQD; M = Cu, Ni) to prepare a composite support. Then, platinum (Pt) nanoparticles were electrodeposited onto the modified Mbpy/CQD support for the preparation of Pt-based catalysts (Pt/Mbpy/CQD) for the electrocatalytic improvement of alcohol oxidation. The influence of Mbpy with electrodeposited Pt nanostructures on CQD support electrodes is particularly discussed in detail through numerous physical characterizations, e.g., SEM, TEM, EDX, XPS, XRD, and elemental mapping. Dispersed Pt nanoparticles with diameters of 3-10 nm can be obtained on the modified Mbpy/CQD supports with suitable chemical and structural conditions for electrocatalytic oxidation improvement. The various prepared Pt/Mbpy/CQD catalysts with different compositions also enhance the kinetics of alcohol oxidation; they have a greater electrochemically active surface area (ECSA) and more development activity for alcohol oxidation than do the Pt/CQD catalysts. For the oxidation of all the selected small alcohol molecules, e.g., methanol, ethanol and isopropanol, the Pt/Cubpy/CQD catalyst composites also mostly exhibited improved catalytic activity, outstanding stability, and lower onset potential (Eonset) and CO tolerance. The favorable performance of the prepared composite catalysts is attributed to their superior ECSA owing to the suitable mixed surface of metal and functional groups of electrodeposited Pt, Mbpy, and CQD on the catalytic composites. Consequently, these as-prepared Pt/Mbpy/CQD composites, which are promising oxidative heterogeneous catalysts, can be used as active and stable catalysts for alcohol oxidation in alkaline solutions.

Investigation on the responses of geotechnical materials to unloading and seepage based on the CFD-DEM coupling method

The unloading issue is prevalent in underground engineering and significantly affects construction safety and the operation of surrounding facilities, while research regarding it is still relatively scarce. A novel CFD-DEM coupling method with dynamic fluid meshes is proposed to reproduce the unloading effect and reveal its micro-scale mechanisms. It adopts uniformly distributed point sets to generate/update fluid meshes and solves with a proposed numerical mapping method. The one-dimensional linear unloading modeling method is further established. The numerically obtained excess pore pressure and rebound deformation under the one-way drained condition are compared with the analytical solutions. The coupling method demonstrates considerable reliability in forecasting the pore pressure response and its advantage for predicting rebound deformation is revealed. The evolutions of the fluid velocity field, particle displacement field, and pore pressure distribution profile are described. The influences of fluid compressibility, unloading rate, unloading volume and initial pore pressure on the unloading characteristics are carefully investigated. The results indicate that the pore pressure is obviously influenced by the selected factors. However, the impact of unloading volume on the final rebound deformation is most significant. Finally, influences of frictionless walls, two-way drained conditions, buoyancy and fluid viscosity on the unloading response are further discussed.

Aspekte të Hartës së Parë të Shqipërisë me Toponimastikënë Gjuhën Shqipe (1902)

Abstract: Over the ages, cartographers, historians, and institutions from diverse European nations and beyond have produced numerous maps and atlases, illustrating the spatial distribution of Albanians and Albania. While these maps hold significant cartographic and historical value, showcasing the ancient authentic ethnicity of Albanians in the Balkans, none have been in Albanian but rather in the languages of foreign cartographers who compiled them. The publication of the first map of Albanian territories with Albanian toponymy in 1902 marks a pivotal historical moment, establishing Albanian cartography. This paper delves into the historical, geographical, linguistic, and cultural importance of this notable achievement. The map was the product of a fruitful collaboration during the Albanian National Awakening between Don Juan Pedro de Aladro Kastrioti, known to Albanians as Gjin Aladro Kastrioti, and Faik bey Konica, the founder and editor of the Albanian National Awakening magazine “Albania”. The paper examines the cartographic and geographical characteristics of the first map with Albanian toponymy from 1902. Noteworthy among the descriptive data of this cartographic work is the extent of the ethnic Albanian presence in the Western Balkans during the early 1900s. Additionally, this paper will detail the invaluable assistance provided by Élisée Reclus, one of the foremost geographers of the time, in guiding the working group involved in constructing the first map of Albania with Albanian toponymy.

Assessment of Dynamic Balance, Muscle Strength and Pain in Young Women with Generalized Joint Hypermobility

This research aims to assess dynamic balance, muscle strength, and pain in young women with generalized jointhypermobility.Research methods: A cross-sectional research design was used in this study. The Beighton scale was used toassess joint hypermobility; the Y test was performed to assess injury risk; a hand-held dynamometer was applied toassess upper extremities’ muscle strength; the McGill tests were used for evaluation of the endurance of trunk muscles’ strength; a numeric analog scale and pain map were used to assess pain intensity and localization.Participants: Twenty-fve young females (age: 22(18–28; 21,16) years; body mass index: (23, 19,2–24, 23,2)kg/m²) participated in this study.Results: The median Beighton score value was 7 (4-9;7.48) points. The Y balance test revealed that 36% (n=9)of the participants were at risk of injury when standing on the dominant leg, and 64% (n=16) when standing on thenon-dominant leg. 64% (n=16) of the young women had a normal grip strength of the dominant hand, and 56%(n=14) had normal non-dominant handgrip strength. Only 20% (n=5) of young women with joint hypermobility hadan abdominal-to-back muscle strength endurance ratio within the normal range and lateral muscle endurance ratiowas within the normal range only in 16% of women.Conclusions: Our pilot study showed that young women with joint hypermobility have reduced hand musclestrength, an imbalance in trunk muscle static endurance and an increased risk of injury in more than half of the subjects. As many as 76% of the young women in this study reported experiencing pain in different areas of the body.Keywords: increased range of movement, fitness, injury risk .

High-resolution cropland mapping in China’s Huang-Huai-Hai Plain: The coupling of machine learning methods and prior information

Numerous map products containing cropland data are currently available. However, due to their low temporal and spatial resolutions and limited accuracy, their practical applications are limited. Thus, research on the precise mapping of croplands with high temporal and spatial resolutions is still urgently needed. The Huang-Huai-Hai Plain, a critical grain production area in China, was used as the research area to produce high-resolution annual cropland maps from 2018 to 2022. Sentinel-2 imagery, digital elevation model (DEM) data, and China Agricultural Ecological Zoning (CAEZ) data were collected. Based on these data, the study area was stratified into different zones, and then the distinct characteristics and optimal timing for differentiating cropland from other land cover types within each zone were analyzed and used as prior information for guiding time-series image compositing. Furthermore, the spectral information divergence (SID) index was used to modify the existing sample migration technique to transfer training samples across years. Via the Google Earth Engine (GEE) platform, the random forest (RF) classification method and positive and unlabeled learning (PUL) method were combined to construct cropland maps from composited images and terrain information from DEMs. Compared with the seasonal or spectral-temporal metric (STM) image composition methods, the image composition method based on prior information significantly improved the distinction between cropland and other land cover types. Moreover, the newly proposed sample migration strategy substantially increased the accuracy of training samples transferred across years. Compared with existing cropland maps from products such as the ESA, ESRI, GlobeLand30, GLAD, and CLCD, the cropland maps generated in this study demonstrated superior accuracy, with average overall accuracy (OA) values from 88.81% to 91.66% for different zones, thus outperforming other products with OA values from 77.53% to 88.90%. This study supports the development of related agricultural and ecological research and provides a valuable reference for cropland mapping.

Using Multi-Source National Forest Inventory Data for the Prediction of Tree Lists of Individual Stands for Long-Term Simulation

Forest resource maps and small area estimates have been produced by combining national forest inventory (NFI) field plot data, multispectral satellite images and numerical map data. We evaluated k-nearest neighbors (k-NN) method-based predictions of forest variables for pixels in predicting tree lists of individual stands, including tree diameters at breast height and tree heights and then calculated stem volumes and tree species proportions. We compared alternative parameters (k-NN) using k of either 1 or 5 according to preliminary plot-level study and applying either measured trees (1-NN_trees) or mean stand characteristics (k-NN_stand). In the 1-NN_trees method, a tree list was generated based on the measured trees of the NFI plots, whereas in the 1-NN_stand and 5-NN_stand methods, a Weibull-based diameter distribution was recovered from the stand characteristics of the same inventory plots. In both methods, tree lists were predicted for each 16 m × 16 m pixel included in the stand compartment. Both methods performed well and resulted in 8–14% differences in the total volume compared with the field inventory of the 27 stands used for the evaluation. Moreover, the main tree species was correctly predicted for 74% of cases. The RMSE in total volume ranged from 25% (5-NN_stand) to 31% (1-NN_stand), while the smallest RMSEs in volume by tree species were 61% for broadleaves and 65% for pine and spruce using the 5-NN_stand. When comparing input data for a long-term growth simulation, the choice of the method was less influential as the effect of the error in the initial stand characteristics decreased over time during the simulation period. After 30-year simulation of the inventoried stands, the respective RMSEs were 9.4% for total volume and 39%, 50% and 59% for tree species, respectively. The satellite-based data with NFI plots were useful for predicting tree lists for pixels of a stand. However, the accuracy for operational forest management was still questionable. For a larger area’s strategic information, the accuracy is considered adequate.

Empowering Data Owners: An Efficient and Verifiable Scheme for Secure Data Deletion

Cloud services have attracted numerous enterprises, organizations, and individual users due to their exceptional computing power and almost limitless storage capacity. A vast amount of business data and private data are continuously uploaded to the cloud platform, driven by a series of attractive services offered by the cloud. Unfortunately, once data is uploaded to the cloud, its owner has no way of ensuring that it is actually deleted as intended. This obviously increases the concerns of data owners about the security of their data, because it is related to the privacy of users. Therefore, there must be a reliable solution to prove that data is deleted as requested by users, to prevent data leakage or abuse. In existing data deletion schemes, most are designed based on cryptographic knowledge rather than erasure or overwrite techniques, in order not to cause incalculable damage to the storage medium. However, most cryptographic-based data deletion schemes, particularly attribute-based encryption, involve numerous complex bilinear mapping operations, which are expensive for most devices. To address this issue, the paper proposes an Efficient and Verifiable Scheme for Secure Data Deletion (EVSD). Firstly, Elliptic Curve Cryptography (ECC) is introduced to achieve efficient encryption of data. Then, leveraging Linear Secret Sharing Scheme (LSSS), fine-grained data deletion policies supporting logical operations are implemented. Finally, the deletion of the data is efficiently verified using the root of the Merkle Hash Tree (MHT) generated by the defined illegal and legal attributes, while the deletion proof is also generated. Satisfactorily, security analysis shows that the EVSD scheme is much more advantageous compared to existing schemes, and a trait likewise is also observed in the performance evaluation.

Geohazard features of the Eastern Sardinia

ABSTRACT The MaGIC project (Marine Geohazard along the Italian Coasts) had the aim of mapping the geohazard in the Italian seas and resulted in numerous maps. In this paper, we present the maps: ‘Maps of Geohazard features of the eastern Sardinian Margin’. The Eastern Sardinia margin has mainly a narrow shelf, which reaches a width of 20 km only to the north. At the base-of-slope, a series of intra-slope basins sits in the structural depressions formed during the opening of the Tyrrhenian back-arc system. Submerged, coastal depositional bodies are present in the Olbia area where the continental shelf is large. They most likely represent the remnants of coastal environments formed during the last rise in sea level. They can represent important geo-resources for application in the issue of coastal erosion management. They are also the site of ecosystems hosting a specific biodiversity, which need to be preserved. In the central and southern part of the mapped area, the shelf is very narrow with an average width of about 4 km. Here, many canyon heads are very close to the coastline. They develop through retrogadational processes. Particularly in those canyons, where the canyon heads reach the coast, sediment instability represents an important source of geohazards to the coastal regions.

Applications of encoding-decoding network on numerical simulation mapping for propeller wake

Numerical Simulation methods of RANS and LES have been widely used to simulate the velocity field induced by propellers. In order to combine advantages of quick computation time from RANS and detailed information from LES, this paper innovatively proposed a customized data-driven encoding-decoding network to achieve mapping from RANS results to LES results. Firstly, an encoding-decoding neural network model was constructed to extract features from RANS/LES for propeller wake. The extracted features with additional information concatenation during the encoding steps were then used to reconstruct the original samples and got a reconstruction error of 1%, which proved the effectiveness of feature extraction ability of the proposed model. The proposed model was then used to map directly from RANS to LES data with a better performance compared to traditional PCA feature extraction and mapping method. Afterwards, the proposed network was applied to two more RANS to LES mapping scenarios to validate the generalization ability. The model could map a coarse-grid RANS to LES of ship propeller with less than 9% MSE error. Similarly, mapped LES of nominal wake was 98% more alike the original LES samples than the RANS samples. As a result, the proposed model could be used either to extract features for potential feature-based performance prediction, or as a quicker method for detailed simulation for propeller wake and nominal wake, thus expedites the design process of ship design.

Geohazard features of the Aeolian Island slopes and the North-Eastern Sicily offshore

ABSTRACT The MaGIC project (Marine Geohazard along the Italian Coasts) had the aim of mapping the geohazard in the Italian seas and resulted in the production of numerous maps covering parts of the Italian Seas. In this paper, we present the maps: ‘The submerged portions of the Aeolian volcanic islands and the north-eastern Sicilian margin’, located in the south-eastern Tyrrhenian Sea. Both areas are affected by active geological processes, which represent important geohazards elements. Inthe submarine parts of the Stromboli volcanoremobilization of volcaniclastic deposits occur along the Sciara del Fuoco, where small-scale instabilities may represent a source of geohazard. Hydrothermal activity occurs on Enarete and Enaretino conical seamounts. The north-eastern Sicilian margin has a narrow continental shelf. Numerous canyon heads indent the shelf and, sometimes, reach close to the coast. Canyons have often a retrogradational trend and further eventual landward shift through sliding can iendangeri coastal or offshore infrastructures. Many of the canyons connect with leveed channels with widespread sediment instability. In the Gioia Basin, some of the channels connect to form the Stromboli slope Valley. Volcanic unrest or local and regional earthquakes are proven to have caused submarine landslides and tsunamis.

Science in the service of politics. The cartographic representation of a local territorial context of the Kingdom of Naples in the early nineteenth century

The erudite priest Marciano Di Leo (1751–1819), a prominent personality in the historical and geographical panorama of his time, not only in his home territory, authored a vast literary and poetic production, but also tried his hand at producing some maps, referring to a province of the Kingdom of Naples. At a time when the principles of geodetic cartography had become increasingly known, even locally, hand in hand with improvements in technology and accuracy of measurements, the author reflects the historical narratives of progress of the European (and Neapolitan) Enlightenment and translates them into an unpublished manuscript of statistical, historical, and geographical nature, accompanied by numerous maps of various scales. The rediscovery of a largely unknown—and therefore not very thorough—minor cartographic production underscores the spread even in more marginal contexts of the most innovative ideas and increasingly precise scientific foundations in the cartographic-mathematical representation of the territory. It also illustrates the role of a number of intellectuals in the service of the political choices of their time, in an attempt-often unrealized-to bring about a decisive change of course in public administration, in accordance with Enlightenment ideals and in the spirit of reform that spread throughout Europe thanks to the French Revolution.

Chaotic-Based Mountain Gazelle Optimizer for Solving Optimization Problems

The Mountain Gazelle Optimizer (MGO) algorithm has become one of the most prominent swarm-inspired meta-heuristic algorithms because of its outstanding rapid convergence and excellent accuracy. However, the MGO still faces premature convergence, making it challenging to leave the local optima if early-best solutions neglect the relevant search domain. Therefore, in this study, a newly developed Chaotic-based Mountain Gazelle Optimizer (CMGO) is proposed with numerous chaotic maps to overcome the above-mentioned flaws. Moreover, the ten distinct chaotic maps were simultaneously incorporated into MGO to determine the optimal values and enhance the exploitation of the most promising solutions. The performance of CMGO has been evaluated using CEC2005 and CEC2019 benchmark functions, along with four engineering problems. Statistical tests like the t-test and Wilcoxon rank-sum test provide further evidence that the proposed CMGO outperforms the existing eminent algorithms. Hence, the experimental outcomes demonstrate that the CMGO produces successful and auspicious results.

Hα reverberation mapping from broad-band photometry of dwarf seyfert 1 galaxy NGC 4395

Abstract NGC 4395 is a dwarf Seyfert 1 galaxy with a possible intermediate-mass black hole of several $\rm {10^4}$ solar masses in its center. As a well-studied object, its broad line region size has been measured via H$\rm {\alpha }$ time lag in numerous spectroscopic reverberation mapping (SRM) and narrow-band photometric reverberation mapping (PRM) campaigns. Here we present its H$\rm {\alpha }$ time lag measurement using broad-band photometric data, with the application of our newly-developed ICCF-Cut method as well as the JAVELIN and χ2 methods. utilizing the minute-cadence multi-band light curves obtained from the $\rm {2}$m FTN and $\rm {10.4}$m GTC telescopes in recent works, we measured its H$\rm {\alpha }$ lag as approximately 40 ∼ 90 minutes from broad-band PRM. With the H$\rm {\alpha }$ emission line velocity dispersion, we calculated its central black hole mass as $\rm M_{\rm BH} = (8\pm 4) \times 10^3\, M_{\rm \odot }$. These results are comparable with previous results obtained by narrow-band PRM and SRM, providing further support to an intermediate-mass black hole in NGC 4395. In addition, our study also validates the ICCF-Cut as an effective method for broad-band PRM, which holds the potential for widespread application in the era of large multi-epoch, high-cadence photometric surveys.