Implementation of the optimizer of SOA system deployment architecture

Optimization of business processes in SOA systems has been done using three separate types of methods: Resource Allocation, Service Scheduling and Service Composition. All three may influence each other, so the new method has been proposed to find an optimal combination of those three. It is based on a genetic algorithm that uses a simulator of the SOA system to evaluate solutions. The article describes a model for the optimization criteria for such solutions. Subsequently, some basic concepts used to implement the simulator and optimizer have been presented. Finally, the performance results of the optimizer have been described, including the conclusions on how they might be improved.Optimization of business processes in SOA systems has been done using three separate types of methods: Resource Allocation, Service Scheduling and Service Composition. All three may influence each other, so the new method has been proposed to find an optimal combination of those three. It is based on a genetic algorithm that uses a simulator of the SOA system to evaluate solutions. The article describes a model for the optimization criteria for such solutions. Subsequently, some basic concepts used to implement the simulator and optimizer have been presented. Finally, the performance results of the optimizer have been described, including the conclusions on how they might be improved

A Search for Optical Variability of Type 2 Quasars in SDSS Stripe 82

Hundreds of Type 2 quasars have been identified in Sloan Digital Sky Survey (SDSS) data, and there is substantial evidence that they are generally galaxies with highly obscured central engines, in accord with unified models for active galactic nuclei (AGNs). A straightforward expectation of unified models is that highly obscured Type 2 AGNs should show little or no optical variability on timescales of days to years. As a test of this prediction, we have carried out a search for variability in Type 2 quasars in SDSS Stripe 82 using difference-imaging photometry. Starting with the Type 2 AGN catalogs of Zakamska et al. (2003) and Reyes et al. (2008), we find evidence of significant g-band variability in 17 out of 173 objects for which light curves could be measured from the Stripe 82 data. To determine the nature of this variability, we obtained new Keck spectropolarimetry observations for seven of these variable AGNs. The Keck data show that these objects have low continuum polarizations (p<~1% in most cases) and all seven have broad H-alpha and/or MgII emission lines in their total (unpolarized) spectra, indicating that they should actually be classified as Type 1 AGNs. We conclude that the primary reason variability is found in the SDSS-selected Type 2 AGN samples is that these samples contain a small fraction of Type 1 AGNs as contaminants, and it is not necessary to invoke more exotic possible explanations such as a population of "naked" or unobscured Type 2 quasars. Aside from misclassified Type 1 objects, the Type 2 quasars do not generally show detectable optical variability over the duration of the Stripe 82 survey.Comment: 14 pages, 8 figures. Accepted for publication in A

The Development and Validation of the Technology-Supported Reflection Inventory

Reflection is an often addressed design goal in Human-Computer Interaction (HCI) research. An increasing number of artefacts for reflection have been developed in recent years. However, evaluating if and how an interactive technology helps a user reflect is still complex. This makes it difficult to compare artefacts (or prototypes) for reflection, impeding future design efforts. To address this issue, we developed the \emph{Technology-Supported Reflection Inventory} (TSRI), which is a scale that evaluates how effectively a system supports reflection. We first created a list of possible scale items based on past work in defining reflection. The items were then reviewed by experts. Next, we performed exploratory factor analysis to reduce the scale to its final length of nine items. Subsequently, we confirmed test-retest validity of our instrument, as well as its construct validity. The TSRI enables researchers and practitioners to compare prototypes designed to support reflection.Comment: CHI Conference on Human Factors in Computing Systems (CHI '21), May 8--13, 2021, Yokohama, Japa

Inertia compensation while scanning screw threads on coordinate-measuring machines

Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up measuring process while still maintaining high accuracy. However, in some cases accuracy drasticaly depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of some dynamic effects while scanning screw threads on coordinate-measuring machines

Comparison of the Structure of Equation Systems and the GPU Multifrontal Solver for Finite Difference, Collocation and Finite Element Method

AbstractThe article is an in-depth comparison of numerical solvers and corresponding solution pro- cesses of the systems of algebraic equations resulting from finite difference, collocation, and finite element approximations. The paper considers recently developed isogeometric versions of the collocation and finite element methods, employing B-splines for the computations and ensuring Cp−1 continuity on the borders of elements for the B-splines of the order p. For solving the systems, we use our GPU implementation of the state-of-the-art parallel multifrontal solver, which leverages modern GPU architectures and allows to reduce the complexity. We analyze the structures of linear equation systems resulting from each of the methods and how different matrix structures lead to different multifrontal solver elimination trees. The paper also considers the flows of multifrontal solver depending on the originally employed method

Exploring the Variable Sky with LINEAR. I. Photometric Recalibration with the Sloan Digital Sky Survey

We describe photometric recalibration of data obtained by the asteroid survey LINEAR. Although LINEAR was designed for astrometric discovery of moving objects, the data set described here contains over 5 billion photometric measurements for about 25 million objects, mostly stars. We use Sloan Digital Sky Survey (SDSS) data from the overlapping ~10,000 deg^2 of sky to recalibrate LINEAR photometry and achieve errors of 0.03 mag for sources not limited by photon statistics with errors of 0.2 mag at r ~ 18. With its 200 observations per object on average, LINEAR data provide time domain information for the brightest four magnitudes of the SDSS survey. At the same time, LINEAR extends the deepest similar wide-area variability survey, the Northern Sky Variability Survey, by 3 mag. We briefly discuss the properties of about 7000 visually confirmed periodic variables, dominated by roughly equal fractions of RR Lyrae stars and eclipsing binary stars, and analyze their distribution in optical and infrared color-color diagrams. The LINEAR data set is publicly available from the SkyDOT Web site

RAPTOR observations of delayed explosive activity in the high-redshift gamma-ray burst GRB 060206

The RAPid Telescopes for Optical Response (RAPTOR) system at Los Alamos National Laboratory observed GRB 060206 starting 48.1 minutes after gamma-ray emission triggered the Burst Alert Telescope (BAT) on-board the Swift satellite. The afterglow light curve measured by RAPTOR shows a spectacular re-brightening by ~1 mag about 1 h after the trigger and peaks at R ~ 16.4 mag. Shortly after the onset of the explosive re-brightening the OT doubled its flux on a time-scale of about 4 minutes. The total R-band fluence received from GRB 060206 during this episode is 2.3e-9 erg/cm2. In the rest frame of the burst (z = 4.045) this yields an isotropic equivalent energy release of ~0.7e50 erg in just a narrow UV band 130 +/- 22 nm. We discuss the implications of RAPTOR observations for untriggered searches for fast optical transients and studies of GRB environments at high redshift.Comment: Submitted to ApJ Letter

Optical Gravitational Lensing Experiment. OGLE-1999-BUL-32: the Longest Ever Microlensing Event -- Evidence for a Stellar Mass Black Hole?

We describe the discovery of the longest microlensing event ever observed, OGLE-1999-BUL-32, also independently identified by the MACHO collaboration as MACHO-99-BLG-22. This unique event has an Einstein radius crossing time of 641 days. The high quality data obtained with difference image analysis shows a small but significant parallax signature. This parallax effect allows one to determine the Einstein radius projected onto the observer plane as rE^hat ~ 29.2AU. The transverse velocity projected onto the observer plane is about 79km/s. We argue that the lens is likely to be have a mass of at least a few solar masses, i.e., it could be a stellar black hole. The black hole hypothesis can be tested using the astrometric microlensing signature with the soon-to-be installed Advanced Camera for Surveys on board the Hubble Space Telescope. Deep X-ray and radio images may also be useful for revealing the nature of the object.Comment: submitted to Monthly Notice