Progressive Domain Adaptation with Contrastive Learning for Object Detection in the Satellite Imagery

State-of-the-art object detection methods applied to satellite and drone imagery largely fail to identify small and dense objects. One reason is the high variability of content in the overhead imagery due to the terrestrial region captured and the high variability of acquisition conditions. Another reason is that the number and size of objects in aerial imagery are very different than in the consumer data. In this work, we propose a small object detection pipeline that improves the feature extraction process by spatial pyramid pooling, cross-stage partial networks, heatmap-based region proposal network, and object localization and identification through a novel image difficulty score that adapts the overall focal loss measure based on the image difficulty. Next, we propose novel contrastive learning with progressive domain adaptation to produce domain-invariant features across aerial datasets using local and global components. We show we can alleviate the degradation of object identification in previously unseen datasets. We create a first-ever domain adaptation benchmark using contrastive learning for the object detection task in highly imbalanced satellite datasets with significant domain gaps and dominant small objects. The proposed method results in a 7.4% increase in mAP performance measure over the best state-of-art

DYNAMICAL CONTACT PARAMETER IDENTIFICATION OF SPINDLE-HOLDER-TOOL ASSEMBLIES USING SOFT COMPUTING TECHNIQUES

In industry, the capability to predict the tool point frequency response function (FRF) is an essential matter in order to ensure the stability of cutting processes. Fast and accurate identification of contact parameters in spindle-holder-tool assemblies is very important issue in machining dynamics analysis. This work is an attempt to illustrate the utility of soft computing techniques in identification and prediction contact parameters of spindle-holder-tool assemblies. In this paper, three soft computing techniques, namely, genetic algorithm (GA), simulated annealing (SA), and particle swarm optimization (PSO) were used for identification of contact dynamics in spindle-holder-tool assemblies. In order to verify the proposed identification approaches, numerical and experimental analysis of the spindle-holder-tool assembly was carried out and the results are presented. Finally, a model based on the adaptive neural fuzzy inference system (ANFIS) was used to predict the dynamical contact parameters at the holder-tool interface of a spindle-holder-tool assembly. Accuracy and performance of the ANFIS model has been found to be satisfactory while validated with experimental results

Production of stilbenes in callus cultures of the Maltese indigenous grapevine variety, Ġellewża

The production of secondary metabolites in tissue culture has been considered as an alternative to the cultivation and harvesting of crops intended for this purpose. The present study was aimed at the growth of callus and production of polyphenolic compound of callus derived from a Maltese indigenous grapevine variety, Ġellewża. Callus was inoculated onto plant growth regulators-enriched Murashige Skoog media (MSm) to determine whether polyphenols are produced in vitro as well as to determine the best combination of plant growth regulators needed for the production of these metabolites. From results obtained, it was observed that the best callus production was obtained by auxin-enriched MSm. In fact, indole acetic acid and indole acetic acid /6-benzyl aminopurine enhanced biomass accumulation (3.04 g and 3.39 g) as opposed to the others (<1.97 g). On the other hand, parameters showing the presence of flavonoids (tonality, 3.80), particularly anthocyanins (24.09 mg/kg) and total polyphenols (1.42 mg/g), were optimum in the presence of cytokinins, particularly 6-benzyl aminopurine. Analysis for single polyphenols revealed a high amount a particular stilbene: polydatin (glucoside of resveratrol). Resveratrol and other typical polyphenols, found in mature berries, were also found in significant quantities, while the other polyphenolic compounds were found in minimal quantities. This is the first study to describe the production and composition of polyphenols in Ġellewża callus cultures. From the results obtained, it can be seen that this grape tissue is an excellent alternative for the production of polyphenols from the stilbene group, which can be upscaled and exploited commercially.This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant no.172017) and by the Malta Council for Science and Technology (Research and Innovation Special Project 2008-01-VOTIVVOM-Valorization of the indigenous vine varieties of Malta: Conservation, Assessment and Innovation [R&I-SP-2008-01]).peer-reviewe

Predviđanje retencije β-diketonato kompleksa u TLC sistemima na silika-gelu primenom kvantitativnog odnosa strukture i retencije

Quantitative structure retention relationships for a series of 30 mixed beta-diketonato complexes of cobalt(III), chromium(III) and ruthenium(III) were derived by multiple linear regression analyses using molecular descriptors obtained by quantum chemical calculations. The retention parameters were obtained by thin layer chromatography on silica gel using mono and two-component solvent systems. The molecular descriptors included in the multiple linear regression analysis were molecular weight, molecular volume, surface area, hydrophilic lipophilic balance, percent hydrophilic surface area, dipole moment, polarizability, refractivity, energy of the highest occupied molecular orbital and energy of the lowest unoccupied molecular orbital. High agreement between the experimental and predicted retention parameters was obtained when polarizability and the hydrophilic lipophilic balance were used as the molecular descriptors. Comparison of the models with those established on polyacrylonitrile showed that the structure of the sorbent is responsible for the chromatographic behaviour of the same compounds. The presented models can be used for the prediction of the retention of new solutes in screening chromatographic systems.U ovom radu kvantifikovan je odnos strukture i retencije 30 mešovitih β-diketonato kompleksa kobalta(III), hroma(III) i rutenijuma(III) primenom multilinearne regresione analize korišćenjem molekulskih deskriptora, koji su dobijeni pomoću kvantno-hemijskih izračunavanja. Retencioni parametri su dobijeni tankoslojnom hromatografijom na silika-gelu primenom mono-i dvokomponetnih rastvarača. Molekulski deskriptori koji su uključeni u multilinearnu regresionu analizu su molekulska težina, molekulska zapremina, površina, hidrofilni-lipofilni balans, procenat hidrofilne površine, dipolni momenat, polarizabilnost, refraktivnost, energija najviše zauzete molekulske orbitale i energija najniže prazne molekulske orbitale. Dobijena je zadovoljavajuća korelacija između eksperimentalnih retencionih parametara i retencionih parametara predviđenih postavljenim modelima, koji sadrže polarizabilnost i hidrofilni-lipofilni balans kao deskriptore. Poređenja ovih modela sa modelima dobijenim na poliakrilonitrilnom sorbentu, za ista jedinjenja, pokazuju da je struktura sorbenta odgovorna za hromatografsko ponašanje. Ovi modeli se mogu koristiti za predviđanje retencije novih jedinjenja u datim hromatografskim sistemima

Vještice u hrvatskim predajama : Zločin i kazna

Rad ne sadrži sažetak

The characteristics of urban soils of Belgrade and their significance for the environment

Имајући у виду да су земљишта у градовима изложена различитим антропогеним притисцима и загађивању различитим полутантима, истраживања у овој докторској дисертацији су усмерена на проучавање физичких и хемијских карактеристика земљишта у Београду и одређивање садржаја тешких метала Zn, Cu, Cd, Pb, Cr и Ni у слојевима земљишта 0-10cm и 10-40cm. За истраживања су изабране различите урбане зоне (централна, приградска, спољна и рубна) и различити тип коришћења земљишта (паркови, индустријски комплекси, саобраћајна чворишта и урбане шуме) у граду. Истраживања су показала да степен урбанизације града и тип коришћења земљишта мењају механички састав земљишта и изазивају промене у pH вредности, садржају лако приступачног облика P и K и присуства CaCO3. У односу на степен урбанизације концентрације тешких метала опадају по градијенту од централне и приградске зоне ка земљиштима у спољној и рубној зони града. У односу на тип коришћења земљишта концентрације ових елемената расту по градијенту од земљишта урбаних шума и паркова ка земљиштима индустријских комплекса и саобраћајних чворишта. Концентрације Ni расту са дубином у свим истраженим земљиштима. Концентрације Zn, Cu, Cd, Pb и Cr опадају са дубином земљишта, изузев у земљиштима руралне зоне града где концентрације Cu, Cd и Pb расту са дубином. Утврђено је да су Cr и Ni геолошког, а Zn, Cu, Cd и Pb антропогеног порекла. Резултати указују на важност успостављања мониторинга концентрација Zn, Cu и Pb у земљиштима Београда, затим Cr и Ni у централним и приградским зонама, и Cd у земљиштима индустријских комплекса и оних уз саобраћајна чворишта. Такође, резултати сугеришу и значај мониторинга есенцијалних елемената, укупног N (због ниског садржаја) и лако приступачних облика P и К (због њихове велике варијабилности).Considering that soils in cities are exposed to different anthropogenic pressures and pollution by different pollutants, research in this doctoral dissertation is focused on studying the physical and chemical characteristics of soils in Belgrade and determining the content of heavy metals Zn, Cu, Cd, Pb, Cr and Ni in soil layers 0-10cm and 10-40cm. Different urban zones (central, suburban, external and rural) and different types of soil use (parks, industrial complexes/zones, road interaction and urban forests) in the city were selected for the research. Research has shown that the degree of urbanization of the city and the type of soil use change the mechanical composition of the soil and cause changes in pH, the content of easily accessible forms of P and K and the presence of CaCO3. In relation to the degree of urbanization, the concentrations of heavy metals decrease according to the gradient from the central and suburban zone to the soils in the external to the rural zone of the city. In relation to the type of soil use, the concentrations of these elements increase in a gradient from the soil of urban forests and parks to the soils of industrial complexes/zones and road interactions. Ni concentrations increase with depth in all investigated soils. Concentrations of Zn, Cu, Cd, Pb and Cr decrease with soil depth, except in soils of the rural zone of the city where concentrations of Cu, Cd and Pb increase with depth. It was determined that Cr and Ni are of geological origin, and Zn, Cu, Cd and Pb are of anthropogenic origin. The results indicate the importance of establishing monitoring of Zn, Cu and Pb concentrations in the soils of Belgrade, then Cr and Ni in the central and suburban zones, and Cd in the soils of industrial complexes and those along road interactions. Also, the results suggest the importance of monitoring essential elements, total N (due to low content) and easily accessible forms P and K (due to their high variability)

PREPORUKE I ZAKLJUčCI RADIONICA

PREPORUKE I ZAKLJUčCI RADIONIC