Face Anti-Spoofing and Deep Learning Based Unsupervised Image Recognition Systems

One of the main problems of a supervised deep learning approach is that it requires large amounts of labeled training data, which are not always easily available. This PhD dissertation addresses the above-mentioned problem by using a novel unsupervised deep learning face verification system called UFace, that does not require labeled training data as it automatically, in an unsupervised way, generates training data from even a relatively small size of data. The method starts by selecting, in unsupervised way, k-most similar and k-most dissimilar images for a given face image. Moreover, this PhD dissertation proposes a new loss function to make it work with the proposed method. Specifically, the method computes loss function k times for both similar and dissimilar images for each input image in order to increase the discriminative power of feature vectors to learn the inter-class and intra-class face variability. The training is carried out based on the similar and dissimilar input face image vector rather than the same training input face image vector in order to extract face embeddings. The UFace is evaluated on four benchmark face verification datasets: Labeled Faces in the Wild dataset (LFW), YouTube Faces dataset (YTF), Cross-age LFW (CALFW) and Celebrities in Frontal Profile in the Wild (CFP-FP) datasets. The results show that we gain an accuracy of 99.40\%, 96.04\%, 95.12\% and 97.89\% respectively. The achieved results, despite being unsupervised, is on par to a similar but fully supervised methods. Another, related to face verification, area of research is on face anti-spoofing systems. State-of-the-art face anti-spoofing systems use either deep learning, or manually extracted image quality features. However, many of the existing image quality features used in face anti-spoofing systems are not well discriminating spoofed and genuine faces. Additionally, State-of-the-art face anti-spoofing systems that use deep learning approaches do not generalize well. Thus, to address the above problem, this PhD dissertation proposes hybrid face anti-spoofing system that considers the best from image quality feature and deep learning approaches. This work selects and proposes a set of seven novel no-reference image quality features measurement, that discriminate well between spoofed and genuine faces, to complement the deep learning approach. It then, proposes two approaches: In the first approach, the scores from the image quality features are fused with the deep learning classifier scores in a weighted fashion. The combined scores are used to determine whether a given input face image is genuine or spoofed. In the second approach, the image quality features are concatenated with the deep learning features. Then, the concatenated features vector is fed to the classifier to improve the performance and generalization of anti-spoofing system. Extensive evaluations are conducted to evaluate their performance on five benchmark face anti-spoofing datasets: Replay-Attack, CASIA-MFSD, MSU-MFSD, OULU-NPU and SiW. Experiments on these datasets show that it gives better results than several of the state-of-the-art anti-spoofing systems in many scenarios

Kokybės užtikrinimo plėtra Bosnijos ir Hercegovinos aukštojo mokslo sektoriuje: teksto analizė

Education is the bedrock of any nation. It is essential for individual and societal growth and development. This study investigates the role of quality assurance in achieving the expected outcome of education in Bosnia and Herzegovina’s higher education sector. A textual analysis is used to examine the National Qualification Framework. The study is based on a documented review and descriptive analysis of student enrollment and programs of studies. The textual analysis is largely qualitative in nature. Unlike the global trend, it can be seen that student enrollment is on the decline in Bosnia and Herzegovina. It was found that quality assurance is an indispensable tool for strengthening the higher education sector and for achieving the desired change and outcomes that education offers. It was also found that study programs and curricula are pivotal for teaching and learning processes, and that a unified qualification framework is essential for achieving set objectives of education at all levels. The study recommended that sound quality assurance systems as well as an appropriate structure for monitoring and accreditation be put in place and be judiciously followed in order to achieve the desired outcomes in conjunction with the set objectives of higher education in the country. Moreover, certain pressures (i.e., democratic, economic, and systemic) and obstacles are looked at that show signs of epistemological, political, and institutional barriers that Bosnia and Herzegovina faces as a developing country Europeanizing its system of education.Švietimas yra kiekvienos tautos pagrindas, būtinas asmens ir visuomenės augimui bei vystymuisi. Šiame tyrime analizuojamas kokybės užtikrinimo vaidmuo siekiant numatomų Bosnijos ir Hercegovinos aukštojo mokslo sektoriaus rezultatų. Nacionalinė kvalifikacijų sistema nagrinėjama pasitelkiant teksto analizės metodą – tyrimas grindžiamas dokumentuota, daugiausia kokybine studentų priėmimo ir studijų programų apžvalga bei aprašomąja analize. Tyrimas atskleidė, kad skirtingai nuo pasaulinių tendencijų, Bosnijoje ir Hercegovinoje studentų skaičius mažėja. Kokybės užtikrinimas yra nepakeičiama priemonė stiprinant aukštojo mokslo sektorių, taip pat norint pasiekti švietimo inicijuojamus pokyčius ir rezultatus. Atskleista ir tai, kad studijų programos ir ugdymo turinys turi lemiamą reikšmę mokymo ir mokymosi procesams, o unifikuota kvalifikacijų sistema yra būtina siekiant užsibrėžtų švietimo tikslų visais lygiais. Tyrime rekomenduojama įdiegti patikimas kokybės užtikrinimo sistemas, atitinkamą stebėsenos ir akreditavimo struktūrą bei jų apgalvotai laikytis, kad šalyje būtų pasiekti keliamus aukštojo mokslo tikslus atitinkantys rezultatai. Be to, tyrime aptariami labai svarbūs ir nuodugniai išanalizuoti lemiami veiksniai (demokratiniai, ekonominiai ir sisteminiai) ir trikdžiai – jie nusako epistemologinių, politinių ir institucinių kliūčių požymius Bosnijoje ir Hercegovinoje, besivystančioje šalyje, kuri yra švietimo sistemos europinimo pavyzdys

The properties of SCUBA cores in the Perseus molecular cloud: the bias of clump-finding algorithms

We present a new analysis of the properties of star-forming cores in the Perseus molecular cloud, identified in SCUBA 850 micron data. Our goal is to determine which core properties can be robustly identified and which depend on the extraction technique. Four regions in the cloud are examined: NGC1333, IC348/HH211, L1448 and L1455. We identify clumps of dust emission using two popular automated algorithms, CLFIND and GAUSSCLUMPS, finding 85 and 122 clumps in total respectively. Some trends are true for both populations: clumps become increasingly elongated over time and are consistent with constant surface brightness objects, with an average brightness ~4 to 10 times larger than the surrounding molecular cloud; the clump mass distribution (CMD) resembles the stellar intial mass function, with a slope alpha = -2.0+/-0.1 for CLFIND and alpha = -3.15+/-0.08 for GAUSSCLUMPS, which straddle the Salpeter value. The mass at which the slope shallows (similar for both algorithms at M~6 Msun) implies a star-forming efficiency of between 10 and 20 per cent. Other trends reported elsewhere depend on the clump-finding technique: we find protostellar clumps are both smaller (for GAUSSCLUMPS) and larger (for CLFIND) than their starless counterparts; the functional form, best-fitting to the CMD, is different for the two algorithms. The GAUSSCLUMPS CMD is best-fitted with a log-normal distribution, whereas a broken power law is best for CLFIND; the reported lack of massive starless cores in previous studies can be seen in the CLFIND but not the GAUSSCLUMPS data. Our approach highlights similarities and differences between the clump populations, illustrating the caution that must be exercised when comparing results from different studies and interpreting the properties of continuum cores.Comment: 19 pages, 17 figures, accepted for publication by MNRA

Effect of the non-electrically conductive spindle on the viscosity measurements of nanofluids subjected to the magnetic field

The viscosity measurements of magnetic nanofluid subjected to the magnetic field are indispensable in various heat transfer studies. Intention of the present discussion is to critically analyze the magnetic field's influence on the working of two viscometers; a Glass capillary viscometer and a DV-E Brookfield viscometer. The novelty of the present study is in the identification of the underlying reason for the massive escalation in viscosity when the magnetic nanofluid is subjected to magnetic field and rectification of the error caused. The stainless-steel spindle in the viscometer is replaced with a non-electrically and non-magnetically conductive nylon spindle to rectify the error. The dynamic viscosity of magnesium ferrite nanofluid of different volume fractions at a temperature of 25 °C in the occurrence of magnetic field was measured. The viscosity of magnetic nanofluid measured using DV-E Brookfield viscometer escalated to a maximum of 725% over the same measured using glass capillary viscometer with the magnetic field application. The application of the nylon spindle in the viscometer eliminates the error caused due to the eddy current formation in the spindle. Therefore, this study recommends using viscometers with non-electrically and non-magnetically conductive spindles for accuracy while measuring the viscosity of magnetic fluids.The Karunya Institute of Technology and Sciences, India, through the Karunya Short Term Research Grant.http://www.elsevier.com/locate/colsurfa2022-08-05hj2022Mechanical and Aeronautical Engineerin

Mass-density relationship in molecular cloud clumps

We study the mass-density relationship n ~ m^x in molecular cloud condensations (clumps), considering various equipartition relations between their gravitational, kinetic, internal and magnetic energies. Clumps are described statistically, with a density distribution that reflects a lognormal probability density function (pdf) in turbulent cold interstellar medium. The clump mass-density exponent $x$ derived at different scales $L$ varies in most of the cases within the range $-2.5\lesssim x \lesssim-0.2$, with a pronounced scale dependence and in consistency with observations. When derived from the global size-mass relationship m ~ l^{\gamma_{glob}} for set of clumps, generated at all scales, the clump mass-density exponent has typical values $-3.0\lesssim x(\gamma_{glob}) \lesssim -0.3$ that depend on the forms of energy, included in the equipartition relations and on the velocity scaling law whereas the description of clump geometry is important when magnetic energy is taken into account.Comment: Accepted in MNRAS, 14 pages, 8 figure

Physical Properties of Dense Cores in the Rho Ophiuchi Main Cloud and A Significant Role of External Pressures in Clustered Star Formation

Using the archive data of the H13CO+ (J=1-0) line emission taken with the Nobeyama 45 m radio telescope with a spatial resolution of about 0.01pc, we have identified 68 dense cores in the central dense region of the rho Ophiuchi main cloud. The H13CO+ data also indicates that the fractional abundance of H13CO+ relative to H2 is roughly inversely proportional to the square root of the H2 column density with a mean of 1.72 x 10^{-11}. The mean radius, FWHM line width, and LTE mass of the identified cores are estimated to be 0.045 +- 0.011 pc, 0.49 +- 0.14 km/s, and 3.4 +- 3.6 Msolar, respectively. The majority of the identified cores have subsonic internal motions. The virial ratio, the ratio of the virial mass to the LTE mass, tends to decrease with increasing the LTE mass and about 60 percent of the cores have virial ratios smaller than 2, indicating that these cores are not transient structures but self-gravitating. The detailed virial analysis suggests that the surface pressure often dominates over the self-gravity and thus plays a crucial role in regulating core formation and evolution. By comparing the rho Oph cores with those in the Orion A molecular cloud observed with the same telescope, we found that the statistical properties of the core physical quantities are similar between the two clouds if the effect of the different spatial resolutions is corrected. The line widths of the rho Oph cores appear to be nearly independent of the core radii over the range of 0.01 - 0.1 pc and deviate upwards from the Heyer & Brunt relation. This may be evidence that turbulent motions are driven by protostellar outflows in the cluster environment.Comment: 45 pages, 14 figures, accepted or publication in ApJ, mpeg movies of figure 3 are available from http://quasar1.ed.niigata-u.ac.jp/~fnakamur/papers/oph1

Turbulent magnetohydrodynamic natural convection in a heat pipe-assisted cavity using disk-shaped magnesium ferrite nanoparticles

The prospect of altering the thermophysical properties of ferrofluid with an influence of magnetic field leads to improving natural convection in various heat transfer systems. This investigation principally focuses on the studies of electromagnetism-based turbulent natural convection heat transfer of low-density disk-shaped magnesium ferrite/water-based ferrofluid, filled in a novel heat pipe-assisted cubical cavity at various volume fractions. Two flat plate heat pipes were used to maintain temperature differences in the cavity. To advance the buoyancy of the working fluid inside the cavity, deliberately low-density ferrofluid containing disk-shaped particles was formulated using the hydrothermal method. The temperature difference between the two heat pipe-assisted vertical walls was sustained with four distinct temperature ranges from 10 to 25 °C. The ferrofluid filled in the cavity was then subjected to magnetic field ranging from 0 to 350 G to understand the thermomagnetic convection effects on heat transfer. The optimal volume fraction of ferrofluid for maximum heat transfer was found to be 0.05% at a wall temperature difference of 25 °C, owing to 23.51% improvement in average heat transfer coefficient along with 33.37% improvement in average Nusselt number when compared to water. With the application of a magnetic field of 350 G, the average heat transfer coefficient was further enhanced by 10.11%, and the average Nusselt number improved by 6.28% for 0.05% volume fraction in comparison to the condition where no magnetic field was applied.https://link.springer.com/journal/13204hj2023Mechanical and Aeronautical Engineerin

A submillimetre survey of the kinematics of the Perseus molecular cloud - III. Clump kinematics

We explore the kinematics of continuum clumps in the Perseus molecular cloud, derived from C18O J=3-2 data. Two populations are examined, identified using the automated algorithms CLFIND and GAUSSCLUMPS on existing SCUBA data. The clumps have supersonic linewidths with distributions which suggest the C18O line probes a lower-density 'envelope' rather than a dense inner core. Similar linewidth distributions for protostellar and starless clumps implies protostars do not have a significant impact on their immediate environment. The proximity to an active young stellar cluster seems to affect the linewidths: those in NGC1333 are greater than elsewhere. In IC348 the proximity to the old IR cluster has little influence, with the linewidths being the smallest of all. A virial analysis suggests that the clumps are bound and close to equipartition. In particular, the starless clumps occupy the same parameter space as the protostars, suggesting they are true stellar precursors and will go on to form stars. We also search for ordered C18O velocity gradients across the face of each core, usually interpreted as rotation. We note a correlation between the directions of the identified gradients and outflows across protostars, indicating we may not have a purely rotational signature. The fitted gradients are larger than found in previous work, probably as a result of the higher resolution of our data and/or outflow contamination. These gradients, if interpreted solely in terms of rotation, suggest that rotation is not dynamically significant. Furthermore, derived specific angular momenta are smaller than observed in previous studies, centred around j~0.001 km/s pc, which indicates we have identified lower levels of rotation, or that the C18O J=3-2 line probes conditions significantly denser and/or colder than n~10^5 per cc and T~10 K.Comment: 20 pages, 20 figures, accepted for publication by MNRAS. Supplementary, on-line only material available from http://www.mrao.cam.ac.uk/~eic22/Papers/CR10b_suppmaterial.pd

Inefficient star formation: The combined effects of magnetic fields and radiative feedback

We investigate the effects of magnetic fields and radiative protostellar feedback on the star formation process using self-gravitating radiation magnetohydrodynamical calculations. We present results from a series of calculations of the collapse of 50 solar mass molecular clouds with various magnetic field strengths and with and without radiative transfer. We find that both magnetic fields and radiation have a dramatic impact on star formation, though the two effects are in many ways complementary. Magnetic fields primarily provide support on large scales to low density gas, whereas radiation is found to strongly suppress small-scale fragmentation by increasing the temperature in the high-density material near the protostars. With strong magnetic fields and radiative feedback the net result is an inefficient star formation process with a star formation rate of ~< 10% per free-fall time that approaches the observed rate, although we have only been able to follow the calculations for ~1/3 of a free-fall time beyond the onset of star formation.Comment: 14 pages, 6 figures, accepted for publication in MNRAS. Movies for all the runs and version with high-res figures available from http://users.monash.edu.au/~dprice/pubs/mclusterRT/ v2: minor changes to match published versio

“If I was going to die I should at least be having fun”: Travel blogs, meaning and tourist experience

Travel blogs are an under-utilised resource for researchers of tourism experiences. They can provide rich insights on how tourists express the transformational effects of their experiences for the self. This study of travel blogs by nineteen British bloggers reveals how elements of the narrative relating to self-reflection and emotions are central to the process of transforming their travel experiences into personally meaningful experiences. Bloggers implicitly and explicitly express how travel contributes to self-identity, signalling self-development. The study contributes to knowledge about the lasting impact of long term travel on people, adding meaning symbolic of an evolving self