Miracle-dz/UniFAR-FTUs huggingface dataset:
Traffic-Aware and Energy-Efficient vNF Placement for Service Chaining: Joint Sampling and Matching Approach

Although network function virtualization (NFV) is a promising approach for providing elastic network functions, it faces several challenges in terms of adaptation to diverse network appliances and reduction of the capital and operational expenses of the service providers. In particular, to deploy service chains, providers must consider different objectives, such as minimizing the network latency or the operational cost, which are coupled objectives that have traditionally been addressed separately. In this paper, the problem of virtual network function (vNF) placement for service chains is studied for the purpose of energy and traffic-aware cost minimization. This problem is formulated as an optimization problem named the joint operational and network traffic cost (<inline-formula><tex-math notation="LaTeX">$\mathsf {OPNET}$</tex-math><alternatives><mml:math><mml:mi mathvariant="sans-serif">OPNET</mml:mi></mml:math><inline-graphic xlink:href="pham-ieq1-2671867.gif"/></alternatives></inline-formula>) problem. First, a sampling-based Markov approximation (MA) approach is proposed to solve the combinatorial NP-hard problem, <inline-formula><tex-math notation="LaTeX">$\mathsf {OPNET}$</tex-math><alternatives><mml:math><mml:mi mathvariant="sans-serif">OPNET</mml:mi></mml:math><inline-graphic xlink:href="pham-ieq2-2671867.gif"/></alternatives></inline-formula>. Even though the MA approach can yield a near-optimal solution, it requires a long convergence time that can hinder its practical deployment. To overcome this issue, a novel approach that combines the MA with matching theory, named as <inline-formula><tex-math notation="LaTeX">$\mathsf {SAMA}$</tex-math><alternatives><mml:math><mml:mi mathvariant="sans-serif">SAMA</mml:mi></mml:math><inline-graphic xlink:href="pham-ieq3-2671867.gif"/></alternatives></inline-formula>, is proposed to find an efficient solution for the original problem <inline-formula><tex-math notation="LaTeX">$\mathsf {OPNET}$</tex-math><alternatives><mml:math><mml:mi mathvariant="sans-serif">OPNET</mml:mi></mml:math><inline-graphic xlink:href="pham-ieq4-2671867.gif"/></alternatives></inline-formula>. Simulation results show that the proposed framework can reduce the total incurred cost by up to 19 percent compared to the existing non-coordinated approach.
Online and Face-to-Face Language Learning: A Comparative Analysis of Oral Proficiency in Introductory Spanish.

The primary resistance to online foreign language teaching often involves questions of spoken mastery of second language. In order to address this concern, this research comparatively assesses undergraduate students’ oral proficiency in online and face-to-face Spanish classes, while taking into account students’ previous second language experience. The sample consisted of 90 undergraduate students, both online and face-to-face, who completed the Versant test at the end of the two semester sequence of Introductory Spanish. The Versant test assessed pronunciation, vocabulary, sentence formation, and fluency as factors of oral proficiency and calculated an overall oral proficiency score. T-test, one-way analysis of variance (ANOVA), and Kruskal-Wallis H test were used to determine whether there were any significant differences between online and face-to-face students’ proficiency scores. The results indicate that there were no statistically significant differences in oral proficiency at the introductory level between students who completed Spanish online and those that participated in face-to-face courses.
Social purchasing and the influence of social networking : a concepual view

Internet has enabled businesses to offer their merchandise through web-based applications, of which recent phenomenon includes online social networks (OSNs). This paper studies the influence of OSNs through the lens of perceived trust (PT), social norm (SN), user satisfaction (US) and perceived behavioral control (PBC) to find out how these influence participants of OSNs continuance buying intention. A model of IS continuance intention of web-based application was developed to test the above factors. The results show that trust in OSN is based mainly on the degree of the social relations that users have with their vendors, because they are members on the network, on top of their experiences of web service use. US was influenced by PBC, while US also influenced SN and PT with PT exhibiting a strong relationship with SN.
Self-directed learning during problem-based learning sessions

Purpose : The study aimed to obtain student perceptions about the inﬂuence of problem-based learning on self-directed learning skills among undergraduate basic science medical students. Methods : A cross-sectional study was conducted among ﬁrst to sixth-semester undergraduate medical students during the last week of July 2016. A previously used instrument was used after obtaining written permission from the developers. The data was analyzed using statistical package for social sciences version 20. The free text comments were tabulated. Results : Fifty-two of the 90 students (58%) participated. The majority of respondents were between 20 to 30 years of age, and of either American or Canadian nationality. The gender distribution was nearly equal. The mean self-management of learning, independent pursuit of learning, learner control of instruction and personal autonomy scores were 2.95, 2.94, 2.98 and 2.87 (maximum possible score being 4). There were no signiﬁcant diﬀerences in the mean domain scores according to age group, gender, and nationality of respondents. Conclusion : Respondents in the present study showed good scores on most statements related to the four dimensions of self-directed learning. Due to the hybrid nature of the curriculum and due to lectures being the dominant teaching-learning strategy, students may have devoted less eﬀort and time to the PBL topics.
Principles Of Physical Optics

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An early phase of environmental effects on galaxy properties unveiled by near-infrared spectroscopy of protocluster galaxies at z > 2

This work presents the results from our near-infrared spectroscopy of narrow-band selected Hα emitters (HAEs) in two rich protoclusters (PKS 1138–262 at z=2.2 and USS 1558–003 at z = 2.5) with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope. These protoclusters are the ancestors of the most massive class of galaxy clusters seen today. The identified HAEs at z > 2 show very high excitation levels as characterized by much higher [Oiii]/Hβ line ratios than those of low-z galaxies. Such a high excitation level is qualitatively driven by their high specific star formation rates (sSFRs) and lower gaseous metallicities. Furthermore, we investigate the environmental dependence of gaseous metallicities by comparing the HAEs in the protoclustrers with those in the general field at similar redshifts. We find that the gaseous metallicities of protocluster galaxies are more chemically enriched than those of field galaxies at a given stellar mass in the range of M⋆ . 10 11 M⊙. This can be attributed to many processes, such as intrinsic (or nature) effects, external (or nurture) effects, and some systematic effects (sampling bias). The intrinsic (nature) effects include the advanced stage of “downsizing” galaxy evolution. On the other hands, the external (nurture) effects include the recycling of chemically enriched gas due to the higher pressure of inter galactic medium or stripping of outer gas in the reservoir in protoclusters. Although, none of the interpretation is perfect, the external effects such as gas recycling or stripping seem to be favored.
Additive Manufacturing of Glass Components - Exploring the Potential of Glass Connections by Fused Deposition Modeling

Glass is an indispensable material in the building industry. The combination of transparency, strength and durability makes it to an unparalleled and desirable material. The technology additive manufacturing (AM) has a potential in the building industry, based on a relatively small amount of repetitions of particular building components and the tendency of applying technology innovations for buildings. Therefore, there is an interest for additive manufacturing with glass. This paper presents and summarizes the results of the preliminary research regarding additive manufacturing of glass components for joining methods for flat glass structures. Different types of glass (borosilicate glass, quartz glass and soda lime silicate glass) are discussed. Experimental investigations of joints are intended to illustrate the performance and potential of AM glass components in case of structural use. Load bearing tests were carried out to quantify the strength and load bearing capacity level of an AM structural component. The thermal residual stresses were examined by photo-elastic tests with polarized lights and scattered light method. The investigations show in principle that load transfer via fused glass joints is possible. The performed research activity is a first step towards the Additive Manufacturing of glass structures on flat glass.
Quasi-linear formulation of MOND

A new formulation of modified Newtonian dynamics (MOND) as a modified-potential theory of gravity is propounded. In effect, the theory dictates that the MOND potential φ produced by a mass distribution ρ is a solution of the Poisson equation for the modified source density ˆ ρ =− (4πG) −1 ∇· g, where g = ν(|g N |/a0)g N , and g N is the Newtonian acceleration field of ρ. This makes φ simply the scalar potential of the algebraic acceleration field g. The theory thus involves solving only linear-differential equations, with one non-linear, algebraic step. It is derivable from an action, satisfies all the usual conservation laws, and gives the correct centre-of-mass acceleration to composite bodies. The theory is akin in some respects to the non-linear Poisson formulation of Bekenstein and Milgrom, but it is different from it, and is obviously easier to apply. The two theories are shown to emerge as natural modifications of a Palatini-type formulation of Newtonian gravity, and are members in a larger class of bi-potential theories.
THE DEPENDENCE OF C iv BROAD ABSORPTION LINE PROPERTIES ON ACCOMPANYING Si iv AND Al iii ABSORPTION: RELATING QUASAR-WIND IONIZATION LEVELS, KINEMATICS, AND COLUMN DENSITIES

We consider how the profile and multi-year variability properties of a large sample of C iv Broad Absorption Line (BAL) troughs change when BALs from Si iv and/or Al iii are present at corresponding velocities, indicating that the line of sight intercepts at least some lower ionization gas. We derive a number of observational results for C iv BALs separated according to the presence or absence of accompanying lower ionization transitions, including measurements of composite profile shapes, equivalent width (EW), characteristic velocities, composite variation profiles, and EW variability. We also measure the correlations between EW and fractional-EW variability for C iv, Si iv, and Al iii. Our measurements reveal the basic correlated changes between ionization level, kinematics, and column density expected in accretion-disk wind models; e.g., lines of sight including lower ionization material generally show deeper and broader C iv troughs that have smaller minimum velocities and that are less variable. Many C iv BALs with no accompanying Si iv or Al iii BALs may have only mild or no saturation.
Effect of Friction Stir Welding Parameters (Rotation and Transverse) Speed on the Transient Temperature Distribution In Friction Stir Welding Of Aa 7020-T53

Three-dimensional nonlinear thermal numerical simulations are conducted for the friction stir welding (FSW) of AA 7020-T53. Three welding cases with tool (rotational and travel) speeds of 900rpm-40mm/min, 1400rpm-16mm/min and 1400rpm-40mm/in are analyzed. The objective is to study the variation of transient temperature in a friction stir welded plate of 5mm workpiece thickness. Based on the experimental records of transient temperature at several specific locations during the friction stir welding process for the AA 7020-T53, thermal numerical simulation is developed. The numerical results show that the temperature field in the FSW process is symmetrically distributed with respect to the welding line, increasing travel speed decreasing transient temperature distribution and increasing rotational speed increase temperature distribution. Experimental data illustrates that peak temperatures are higher on the advancing side than the retreating side. Comparison with the temperature measured by the thermocouples records shows that the results from the present numerical simulation have good agreement with the test data.
Mid-infrared interferometry of massive young stellar objects - II. Evidence for a circumstellar disk surrounding the Kleinmann-Wright object

The formation scenario for massive stars is still under discussion. To further constrain current theories, it is vital to spatially resolve the structures from which material accretes onto massive young stellar objects (MYSOs). Due to the small angular extent of MYSOs, one needs to overcome the limitations of conventional thermal infrared imaging, regarding spatial resolution, in order to get observational access to the inner structure of these objects. We employed mid-infrared interferometry, using the MIDI instrument on the ESO/VLTI, to investigate the Kleinmann-Wright Object, a massive young stellar object previously identified as a Herbig Be star precursor. Dispersed visibility curves in the N-band (8-13 μm) have been obtained at 5 interferometric baselines. We show that the mid-infrared emission region is resolved. A qualitative analysis of the data indicates a non-rotationally symmetric structure, e.g. the projection of an inclined disk. We employed extensive radiative transfer simulations based on spectral energy distribution fitting. Since SED-only fitting usually yields degenerate results, we first employed a statistical analysis of the parameters provided by the radiative transfer models. In addition, we compared the ten best-fitting self-consistent models to the interferometric observations. Our analysis of the Kleinmann-Wright Object suggests the existence of a circumstellar disk of 0.1 M ⊙ at an intermediate inclination of 76°, while an additional dusty envelope is not necessary for fitting the data. Furthermore, we demonstrate that the combination of IR interferometry with radiative transfer simulations has the potential to resolve ambiguities arising from the analysis of spectral energy distributions alone.
Journey to the Center of the Earth

We survey some results on travel time tomography. The question is whether we can determine the anisotropic index of refraction of a medium by measuring the travel times of waves going through the medium. This can be recast as geometry problems, the boundary rigidity problem and the lens rigidity problem. The boundary rigidity problem is whether we can determine a Riemannian metric of a compact Riemannian manifold with boundary by measuring the distance function between boundary points. The lens rigidity problem problem is to determine a Riemannian metric of a Riemannian manifold with boundary by measuring for every point and direction of entrance of a geodesic the point of exit and direction of exit and its length. The linearization of these two problems is tensor tomography. The question is whether one can determine a symmetric two-tensor from its integrals along geodesics. We emphasize recent results on boundary and lens rigidity and in tensor tomography in the partial data case.
Motion of charged test particles in Reissner-Nordström spacetime

We investigate the circular motion of charged test particles in the gravitational field of a charged mass described by the Reissner-Nordstr\"om (RN) spacetime. We study in detail all the spatial regions where circular motion is allowed around either black holes or naked singularities. The effects of repulsive gravity are discussed by finding all the circles at which a particle can have vanishing angular momentum. We show that the geometric structure of stable accretion disks, made of only test particles moving along circular orbits around the central body, allows us to clearly distinguish between black holes and naked singularities.
Global Solutions for the Two-Component Camassa–Holm System

We prove existence of a global conservative solution of the Cauchy problem for the two-component Camassa–Holm (2CH) system on the line, allowing for nonvanishing and distinct asymptotics at plus and minus infinity. The solution is proven to be smooth as long as the density is bounded away from zero. Furthermore, we show that by taking the limit of vanishing density in the 2CH system, we obtain the global conservative solution of the (scalar) Camassa–Holm equation, which provides a novel way to define and obtain these solutions. Finally, it is shown that while solutions of the 2CH system have infinite speed of propagation, singularities travel with finite speed.
XML query evaluation

XML is now widely used and management of XML data has become important. To this end, there has been work on the native management of XML data in a database to utilize the different capabilities of such a system like transaction management and indexing structures. At the heart of such a native XML database is the query evaluator, which provides access methods specifically tailored for XML data manipulation. The design of efficient access methods is the topic of this thesis. The most frequently used operation in an XML database is called structural join. Almost all XML queries contain at least one structural join. The structural join returns matches to a pattern from an XML document. We introduce a new efficient family of algorithms to address this task. These algorithms use a stack data structure that exploits the hierarchy of XML in favor of performance. We then develop variants that permit the combination of other operators, including projection, set difference, and universal quantification, with the structural join operation for greater efficiency. An important value provided by XML is the seamless representation of text and structured data. Querying the text with regard to the structure yields fast and accurate results. However, standard database query paradigms are not suitable for querying text. We introduce the TIX algebra for this purpose, and develop new access methods capable of efficiently computing and combining scores associated with intermediate results. In such applications, one is typically interested in only a few results with the highest scores. We develop new access methods to find results that score within a margin of error from the actual top results. These new access methods out-perform getting actual top results by at least an order of magnitude.
THE HUNT FOR EXOMOONS WITH KEPLER (HEK). IV. A SEARCH FOR MOONS AROUND EIGHT M DWARFS

With their smaller radii and high cosmic abundance, transiting planets around cool stars hold a unique appeal. As part of our ongoing project to measure the occurrence rate of extrasolar moons, in this work we present results from a survey focusing on eight Kepler planetary candidates associated with M dwarfs. Using photodynamical modeling and Bayesian multimodal nested sampling, we find no compelling evidence for an exomoon in these eight systems. Upper limits on the presence of such bodies probe down to masses of ∼0.4 M⊕ in the best case. For KOI-314, we are able to confirm the planetary nature of two out of the three known transiting candidates using transit timing variations. Of particular interest is KOI-314c, which is found to have a mass of M⊕, making it the lowest mass transiting planet discovered to date. With a radius of R⊕, this Earth-mass world is likely enveloped by a significant gaseous envelope comprising % of the planet by radius. We also find evidence to support the planetary nature of KOI-784 via transit timing, but we advocate further observations to verify the signals. In both systems, we infer that the inner planet has a higher density than the outer world, which may be indicative of photo-evaporation. These results highlight both the ability of Kepler to search for sub-Earth-mass moons and the exciting ancillary science that often results from such efforts.
ROTATIONAL EVOLUTION OF MAGNETARS IN THE PRESENCE OF A FALLBACK DISK

Magnetars may have a strong surface dipole field. Observationally, two magnetars may have passive fallback disks. In the presence of a fallback disk, the rotational evolution of magnetars may be changed. In the self-similar fallback disk model, it is found that (1) when the disk mass is significantly lower than 10−6 M⊙, the magnetar is unaffected by the fallback disk and it will be a normal magnetar. (2) When the disk mass is high but the surface dipole field of the magnetar is about or below 1014 G, the magnetar will also be a normal magnetar. A magnetar plus a passive fallback disk system is expected. This may correspond to the observations of magnetars 4U 0142+61 and 1E 2259+586. (3) When the disk mass is high and the surface dipole field of the magnetar is as high as 4 × 1015 G, the magnetar will evolve from the ejector phase to the propeller phase, and then enter rotational equilibrium. The magnetar will be slowed down quickly in the propeller phase. The final rotational period can be as high 2 × 104 s. This may correspond to the super-slow magnetar in the supernova remnant RCW 103. Therefore, the three types of magnetars can be understood in a unified way.
Dramatic increase of the onset critical temperature and critical field of elemental Sn in the form of thin nanowires

Sn is a well-known classical superconductor on the border between type I and type II with critical temperature of 3.722K and critical field of 0.031T. We show by means of specific heat and electric magneto-transport data that its critical parameters can be dramatically increased if it is brought in the form of loosely bound bundles of thin nanowires. The specific heat displays a pronounced double phase transition at 3.7K and 5.5K, which we attribute to the inner 'bulk' contribution of the nanowires and to the surface contribution, respectively. The latter is visible only because of the large volume fraction of the surface layer in relation to their bulk inner volume. The upper transition coincides with the onset of the resistive transition, while zero resistance is gradually approached below the lower transition. The large coherence length of 230nm at 0K likely actuates a Josephson coupling between adjacent neighboring nanowires and thus suppresses the effect of 1D phase fluctuations along the nanowires, and stabilizes 3D phase coherence throughout the entire network with zero resistance. A magnetic field of more than 3T is required to restore the normal state, which means that the critical field is enhanced by about two orders of magnitude with respect to Sn in its bulk form.