Thermal infrared and optical photometry of Asteroidal Comet C/2002 CE10

Science.gov (United States)

Sekiguchi, Tomohiko; Miyasaka, Seidai; Dermawan, Budi; Mueller, Thomas; Takato, Naruhisa; Watanabe, Junichi; Boehnhardt, Hermann

2018-04-01

C/2002 CE10 is an object in a retrograde elliptical orbit with Tisserand parameter - 0.853 indicating a likely origin in the Oort Cloud. It appears to be a rather inactive comet since no coma and only a very weak tail was detected during the past perihelion passage. We present multi-color optical photometry, lightcurve and thermal mid-IR observations of the asteroidal comet. With the photometric analysis in BVRI, the surface color is found to be redder than asteroids, corresponding to cometary nuclei and TNOs/Centaurs. The time-resolved differential photometry supports a rotation period of 8.19 ± 0.05 h. The effective diameter and the geometric albedo are 17.9 ± 0.9 km and 0.03 ± 0.01, respectively, indicating a very dark reflectance of the surface. The dark and redder surface color of C/2002 CE10 may be attribute to devolatilized material by surface aging suffered from the irradiation by cosmic rays or from impact by dust particles in the Oort Cloud. Alternatively, C/2002 CE10 was formed of very dark refractory material originally like a rocky planetesimal. In both cases, this object lacks ices (on the surface at least). The dynamical and known physical characteristics of C/2002 CE10 are best compatible with those of the Damocloids population in the Solar System, that appear to be exhaust cometary nucleus in Halley-type orbits. The study of physical properties of rocky Oort cloud objects may give us a key for the formation of the Oort cloud and the solar system.

KNOWLEDGE-BASED OBJECT DETECTION IN LASER SCANNING POINT CLOUDS

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F. Boochs

2012-07-01

Full Text Available Object identification and object processing in 3D point clouds have always posed challenges in terms of effectiveness and efficiency. In practice, this process is highly dependent on human interpretation of the scene represented by the point cloud data, as well as the set of modeling tools available for use. Such modeling algorithms are data-driven and concentrate on specific features of the objects, being accessible to numerical models. We present an approach that brings the human expert knowledge about the scene, the objects inside, and their representation by the data and the behavior of algorithms to the machine. This “understanding” enables the machine to assist human interpretation of the scene inside the point cloud. Furthermore, it allows the machine to understand possibilities and limitations of algorithms and to take this into account within the processing chain. This not only assists the researchers in defining optimal processing steps, but also provides suggestions when certain changes or new details emerge from the point cloud. Our approach benefits from the advancement in knowledge technologies within the Semantic Web framework. This advancement has provided a strong base for applications based on knowledge management. In the article we will present and describe the knowledge technologies used for our approach such as Web Ontology Language (OWL, used for formulating the knowledge base and the Semantic Web Rule Language (SWRL with 3D processing and topologic built-ins, aiming to combine geometrical analysis of 3D point clouds, and specialists’ knowledge of the scene and algorithmic processing.

Knowledge-Based Object Detection in Laser Scanning Point Clouds

Science.gov (United States)

Boochs, F.; Karmacharya, A.; Marbs, A.

2012-07-01

Object identification and object processing in 3D point clouds have always posed challenges in terms of effectiveness and efficiency. In practice, this process is highly dependent on human interpretation of the scene represented by the point cloud data, as well as the set of modeling tools available for use. Such modeling algorithms are data-driven and concentrate on specific features of the objects, being accessible to numerical models. We present an approach that brings the human expert knowledge about the scene, the objects inside, and their representation by the data and the behavior of algorithms to the machine. This "understanding" enables the machine to assist human interpretation of the scene inside the point cloud. Furthermore, it allows the machine to understand possibilities and limitations of algorithms and to take this into account within the processing chain. This not only assists the researchers in defining optimal processing steps, but also provides suggestions when certain changes or new details emerge from the point cloud. Our approach benefits from the advancement in knowledge technologies within the Semantic Web framework. This advancement has provided a strong base for applications based on knowledge management. In the article we will present and describe the knowledge technologies used for our approach such as Web Ontology Language (OWL), used for formulating the knowledge base and the Semantic Web Rule Language (SWRL) with 3D processing and topologic built-ins, aiming to combine geometrical analysis of 3D point clouds, and specialists' knowledge of the scene and algorithmic processing.

Comet C/2017 K2 (PANSTARRS): Dynamically Old or New?

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de la Fuente Marcos, Raúl; de la Fuente Marcos, Carlos

2018-04-01

At discovery time, C/2017 K2 (PANSTARRS) was the second most distant inbound active comet ever observed. It has been argued that this object is in the process of crossing the inner Solar System for the first time, but other authors have concluded that it is dynamically old. We have performed full N-body simulations for 3 Myr into the past using the latest public orbit determination for this object and most of them, 67%, are consistent with a bound and dynamically old Oort cloud comet, but about 29% of the studied orbits are compatible with an interstellar origin. Our independent calculations strongly suggest that C/2017 K2 is not a dynamically new Oort cloud comet.

Encounters of The Solar System With Molecular Clouds

International Nuclear Information System (INIS)

Wickramasinghe, J. T.

2008-01-01

The solar system has penetrated about 5 -- 10 giant molecular clouds over its history, and passes within 5 parsecs of a star-forming nebula every 100 million years or so. Numerical simulations of the effect of such encounters in perturbing the Oort cloud of comets are carried out using standard n-body computational techniques. It is found that the ingress of comets into the inner planetary system during such encounters amounts to factors of ∼100 over the average. During an encounter the impact rate of comets onto Earth increases by a comparable factor. The of ages of impact craters on the Earth is shown to be consistent with predictions from the model

OSSOS. V. Diffusion in the Orbit of a High-perihelion Distant Solar System Object

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Bannister, Michele T.; Shankman, Cory; Volk, Kathryn; Chen, Ying-Tung; Kaib, Nathan; Gladman, Brett J.; Jakubik, Marian; Kavelaars, J. J.; Fraser, Wesley C.; Schwamb, Megan E.; Petit, Jean-Marc; Wang, Shiang-Yu; Gwyn, Stephen D. J.; Alexandersen, Mike; Pike, Rosemary E.

2017-06-01

We report the discovery of the minor planet 2013 SY99 on an exceptionally distant, highly eccentric orbit. With a perihelion of 50.0 au, 2013 SY99’s orbit has a semimajor axis of 730 ± 40 au, the largest known for a high-perihelion trans-Neptunian object (TNO), and well beyond those of (90377) Sedna and 2012 VP113. Yet, with an aphelion of 1420 ± 90 au, 2013 SY99’s orbit is interior to the region influenced by Galactic tides. Such TNOs are not thought to be produced in the current known planetary architecture of the solar system, and they have informed the recent debate on the existence of a distant giant planet. Photometry from the Canada-France-Hawaii Telescope, Gemini North, and Subaru indicate 2013 SY99 is ˜250 km in diameter and moderately red in color, similar to other dynamically excited TNOs. Our dynamical simulations show that Neptune’s weak influence during 2013 SY99’s perihelia encounters drives diffusion in its semimajor axis of hundreds of astronomical units over 4 Gyr. The overall symmetry of random walks in the semimajor axis allows diffusion to populate 2013 SY99’s orbital parameter space from the 1000 to 2000 au inner fringe of the Oort cloud. Diffusion affects other known TNOs on orbits with perihelia of 45 to 49 au and semimajor axes beyond 250 au. This provides a formation mechanism that implies an extended population, gently cycling into and returning from the inner fringe of the Oort cloud.

HERBIG-HARO OBJECTS IN THE LUPUS I AND III MOLECULAR CLOUDS

International Nuclear Information System (INIS)

Wang Hongchi; Henning, Thomas

2009-01-01

We performed a deep search for Herbig-Haro (HH) objects toward the Lupus I and III clouds, covering a sky area of ∼ 1 and ∼ 0.5 deg 2 , respectively. In total, 11 new HH objects, HH 981--991, are discovered. The HH objects both in Lupus I and in Lupus III tend to be concentrated in small areas. The HH objects detected in Lupus I are located in a region of radius 0.26 pc near the young star Sz 68. The abundance of HH objects shows that this region of the cloud is active in on-going star formation. HH objects in the Lup III cloud are concentrated in the central part of the cloud around the Herbig Ae/Be stars HR 5999 and 6000. HH 981 and 982 in Lupus I are probably driven by the young brown dwarf SSTc2d J154457.9-342340 which has a mass of 50 M J . HH 990 and 991 in Lup III align well with the HH 600 jet emanating from the low-mass star Par-Lup3-4, and are probably excited by this low-mass star of spectral type M5. High proper motions for HH 228 W, E, and E2 are measured, which confirms that they are excited by the young star Th 28. In contrast, HH 78 exhibits no measurable proper motion in the time span of 18 years, indicating that HH 78 is unlikely part of the HH 228 flow. The HH objects in Lup I and III are generally weak in terms of brightness and dimension in comparison to HH objects we detected with the same technique in the R CrA and Cha I clouds. Through a comparison with the survey results from the Spitzer c2d program, we find that our optical survey is more sensitive, in terms of detection rate, than the Spitzer IRAC survey to high-velocity outflows in the Lup I and III clouds.

e-Learning objects in the cloud: SCORM compliance, creation and deployment options

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Stephanie Day

2017-12-01

Full Text Available In the field of education, cloud computing is changing the way learning is delivered and experienced, by providing software, storage, teaching resources, artefacts, and knowledge that can be shared by educators on a global scale. In this paper, the first objective is to understand the general trends in educational use of the cloud, particularly the provision of large scale education opportunities, use of open and free services, and interoperability of learning objects. A review of current literature reveals the opportunities and issues around managing learning and teaching related knowledge in the cloud. The educational use of the cloud will continue to grow as the services, pedagogies, personalization, and standardization of learning are refined and adopted. Secondly, the paper presents an example of how the cloud can support learning opportunities using SCORM interoperable learning objects. The case study findings show that, while the use of SCORM enables a variety of trackable learning opportunities, the constraints of maintaining the currency of the learning also need to be considered. It is recommended that the SCORM content are combined with cloud based student activities. These learning objects can be used to support alternative learning opportunities within blended and online learning environments.

a Point Cloud Classification Approach Based on Vertical Structures of Ground Objects

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Zhao, Y.; Hu, Q.; Hu, W.

2018-04-01

This paper proposes a novel method for point cloud classification using vertical structural characteristics of ground objects. Since urbanization develops rapidly nowadays, urban ground objects also change frequently. Conventional photogrammetric methods cannot satisfy the requirements of updating the ground objects' information efficiently, so LiDAR (Light Detection and Ranging) technology is employed to accomplish this task. LiDAR data, namely point cloud data, can obtain detailed three-dimensional coordinates of ground objects, but this kind of data is discrete and unorganized. To accomplish ground objects classification with point cloud, we first construct horizontal grids and vertical layers to organize point cloud data, and then calculate vertical characteristics, including density and measures of dispersion, and form characteristic curves for each grids. With the help of PCA processing and K-means algorithm, we analyze the similarities and differences of characteristic curves. Curves that have similar features will be classified into the same class and point cloud correspond to these curves will be classified as well. The whole process is simple but effective, and this approach does not need assistance of other data sources. In this study, point cloud data are classified into three classes, which are vegetation, buildings, and roads. When horizontal grid spacing and vertical layer spacing are 3 m and 1 m respectively, vertical characteristic is set as density, and the number of dimensions after PCA processing is 11, the overall precision of classification result is about 86.31 %. The result can help us quickly understand the distribution of various ground objects.

Cloud fluid models of gas dynamics and star formation in galaxies

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Struck-Marcell, Curtis; Scalo, John M.; Appleton, P. N.

1987-01-01

The large dynamic range of star formation in galaxies, and the apparently complex environmental influences involved in triggering or suppressing star formation, challenges the understanding. The key to this understanding may be the detailed study of simple physical models for the dominant nonlinear interactions in interstellar cloud systems. One such model is described, a generalized Oort model cloud fluid, and two simple applications of it are explored. The first of these is the relaxation of an isolated volume of cloud fluid following a disturbance. Though very idealized, this closed box study suggests a physical mechanism for starbursts, which is based on the approximate commensurability of massive cloud lifetimes and cloud collisional growth times. The second application is to the modeling of colliding ring galaxies. In this case, the driving processes operating on a dynamical timescale interact with the local cloud processes operating on the above timescale. The results is a variety of interesting nonequilibrium behaviors, including spatial variations of star formation that do not depend monotonically on gas density.

Multi-objective evacuation routing optimization for toxic cloud releases

International Nuclear Information System (INIS)

Gai, Wen-mei; Deng, Yun-feng; Jiang, Zhong-an; Li, Jing; Du, Yan

2017-01-01

This paper develops a model for assessing the risks associated with the evacuation process in response to potential chemical accidents, based on which a multi-objective evacuation routing model for toxic cloud releases is proposed taking into account that the travel speed on each arc will be affected by disaster extension. The objectives of the evacuation routing model are to minimize travel time and individual evacuation risk along a path respectively. Two heuristic algorithms are proposed to solve the multi-objective evacuation routing model. Simulation results show the effectiveness and feasibility of the model and algorithms presented in this paper. And, the methodology with appropriate modification is suitable for supporting decisions in assessing emergency route selection in other cases (fires, nuclear accidents). - Highlights: • A model for assessing and visualizing the risks is developed. • A multi-objective evacuation routing model is proposed for toxic cloud releases. • A modified Dijkstra algorithm is designed to obtain an solution of the model. • Two heuristic algorithms have been developed as the optimization tool.

Calvin, Augustine of Hippo and South Africa: in discussion with Johannes van Oort

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J.W. Hofmeyr

2010-07-01

Full Text Available In this article the curtain is raised on the interesting and fascinating relation between Augustine of Hippo and John Cal- vin from Geneva, as seen through the eyes of the Dutch scholar Johannes van Oort. The influences of and links between Augustine and Calvin are immense. This has been the focus of various studies in the past. The purpose of this article is, however, not to re-invent the wheel about these relations, but rather to reflect on one of the most eminent scholars on Augustine, i.e. Van Oort’s vision on these links and to enter into a dialogue with him so as to shed some new light on this topic and on some aspects related to ecclesiology. After attention to the use of Augustine by Calvin, the focus is on the discussion with Van Oort and eventually on the relevance of this for us in South(ern Africa. It is concluded that in this era of post- modernism and relativism as well much can be learnt from both Augustine and Calvin, and especially with regard to the well- being of the church.

Background Noises Versus Intraseasonal Variation Signals: Small vs. Large Convective Cloud Objects From CERES Aqua Observations

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Xu, Kuan-Man

2015-01-01

During inactive phases of Madden-Julian Oscillation (MJO), there are plenty of deep but small convective systems and far fewer deep and large ones. During active phases of MJO, a manifestation of an increase in the occurrence of large and deep cloud clusters results from an amplification of large-scale motions by stronger convective heating. This study is designed to quantitatively examine the roles of small and large cloud clusters during the MJO life cycle. We analyze the cloud object data from Aqua CERES (Clouds and the Earth's Radiant Energy System) observations between July 2006 and June 2010 for tropical deep convective (DC) and cirrostratus (CS) cloud object types according to the real-time multivariate MJO index, which assigns the tropics to one of the eight MJO phases each day. The cloud object is a contiguous region of the earth with a single dominant cloud-system type. The criteria for defining these cloud types are overcast footprints and cloud top pressures less than 400 hPa, but DC has higher cloud optical depths (=10) than those of CS (background noises resulting from various types of the tropical waves with different wavenumbers and propagation speeds/directions.

On the Detectability of Interstellar Objects Like 1I/'Oumuamua

Science.gov (United States)

Ragozzine, Darin

2018-04-01

Almost since Oort's 1950 hypothesis of a tenuously bound cloud of comets, planetary formation theorists have realized that the process of planet formation must have ejected very large numbers of planetesimals into interstellar space. Unforunately, these objects are distributed over galactic volumes, while they are only likely to be detectable if they pass within a few AU of Earth, resulting in an incredibly sparse detectable population. Furthermore, hypotheses for the formation and distribution of these bodies allows for uncertainties of orders of magnitude in the expected detection rate: our analysis suggested LSST would discover 0.01-100 objects during its lifetime (Cook et al. 2016). The discovery of 1I/'Oumuamua by a survey less powerful that LSST indicates either a low probability event and/or that properties of this population are on the more favorable end of the spectrum. We revisit the detailed detection analysis of Cook et al. 2016 in light of the detection of 1I/'Oumuamua. We use these results to better understand 1I/'Oumuamua and to update our assessment of future detections of interstellar objects. We highlight some key questions that can be answered only by additional discoveries.

3-D OBJECT RECOGNITION FROM POINT CLOUD DATA

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W. Smith

2012-09-01

Full Text Available The market for real-time 3-D mapping includes not only traditional geospatial applications but also navigation of unmanned autonomous vehicles (UAVs. Massively parallel processes such as graphics processing unit (GPU computing make real-time 3-D object recognition and mapping achievable. Geospatial technologies such as digital photogrammetry and GIS offer advanced capabilities to produce 2-D and 3-D static maps using UAV data. The goal is to develop real-time UAV navigation through increased automation. It is challenging for a computer to identify a 3-D object such as a car, a tree or a house, yet automatic 3-D object recognition is essential to increasing the productivity of geospatial data such as 3-D city site models. In the past three decades, researchers have used radiometric properties to identify objects in digital imagery with limited success, because these properties vary considerably from image to image. Consequently, our team has developed software that recognizes certain types of 3-D objects within 3-D point clouds. Although our software is developed for modeling, simulation and visualization, it has the potential to be valuable in robotics and UAV applications. The locations and shapes of 3-D objects such as buildings and trees are easily recognizable by a human from a brief glance at a representation of a point cloud such as terrain-shaded relief. The algorithms to extract these objects have been developed and require only the point cloud and minimal human inputs such as a set of limits on building size and a request to turn on a squaring option. The algorithms use both digital surface model (DSM and digital elevation model (DEM, so software has also been developed to derive the latter from the former. The process continues through the following steps: identify and group 3-D object points into regions; separate buildings and houses from trees; trace region boundaries; regularize and simplify boundary polygons; construct complex

3-D Object Recognition from Point Cloud Data

Science.gov (United States)

Smith, W.; Walker, A. S.; Zhang, B.

2011-09-01

The market for real-time 3-D mapping includes not only traditional geospatial applications but also navigation of unmanned autonomous vehicles (UAVs). Massively parallel processes such as graphics processing unit (GPU) computing make real-time 3-D object recognition and mapping achievable. Geospatial technologies such as digital photogrammetry and GIS offer advanced capabilities to produce 2-D and 3-D static maps using UAV data. The goal is to develop real-time UAV navigation through increased automation. It is challenging for a computer to identify a 3-D object such as a car, a tree or a house, yet automatic 3-D object recognition is essential to increasing the productivity of geospatial data such as 3-D city site models. In the past three decades, researchers have used radiometric properties to identify objects in digital imagery with limited success, because these properties vary considerably from image to image. Consequently, our team has developed software that recognizes certain types of 3-D objects within 3-D point clouds. Although our software is developed for modeling, simulation and visualization, it has the potential to be valuable in robotics and UAV applications. The locations and shapes of 3-D objects such as buildings and trees are easily recognizable by a human from a brief glance at a representation of a point cloud such as terrain-shaded relief. The algorithms to extract these objects have been developed and require only the point cloud and minimal human inputs such as a set of limits on building size and a request to turn on a squaring option. The algorithms use both digital surface model (DSM) and digital elevation model (DEM), so software has also been developed to derive the latter from the former. The process continues through the following steps: identify and group 3-D object points into regions; separate buildings and houses from trees; trace region boundaries; regularize and simplify boundary polygons; construct complex roofs. Several case

Observations of the interstellar ice grain feature in the Taurus molecular clouds

International Nuclear Information System (INIS)

Whittet, D.C.B.; Bode, H.F.; Longmore, A.J.; Baines, D.W.T.; Evans, A.

1983-01-01

Although water ice was originally proposed as a major constituent of the interstellar grain population (e.g. Oort and van de Hulst, 1946), the advent of infrared astronomy has shown that the expected absorption due to O-H stretching vibrations at 3 μm is illusive. Observations have in fact revealed that the carrier of this feature is apparently restricted to regions deep within dense molecular clouds (Merrill et al., 1976; Willner et al., 1982). However, the exact carrier of this feature is still controversial, and many questions remain as to the conditions required for its appearance. It is also uncertain whether it is restricted to circumstellar shells, rather than the general cloud medium. Detailed discussion of the 3 μm band properties is given elsewhere in this volume. 15 references, 4 figures

FORMATION CONDITIONS OF ICY MATERIALS IN COMET C/2004 Q2 (MACHHOLZ). I. MIXING RATIOS OF ORGANIC VOLATILES

International Nuclear Information System (INIS)

Kobayashi, Hitomi; Kawakita, Hideyo

2009-01-01

We observed comet C/2004 Q2 (Machholz) with the Keck II telescope in late 2005 January and we obtained the spectra of C/2004 Q2 including many emission lines of volatile species such as H 2 O, HCN, C 2 H 2 , NH 3 , CH 4 , C 2 H 6 , CH 3 OH, and H 2 CO with high-signal-to-noise ratios. Based on our observations, we determined the mixing ratios of the molecules relative to H 2 O in C/2004 Q2. Since C/2004 Q2 is one of Oort Cloud comets, it is interesting to compare our results with other Oort Cloud comets. The mixing ratios of C 2 H 2 /H 2 O and C 2 H 6 /H 2 O in C/2004 Q2 are lower than typical Oort Cloud comets. Especially, C 2 H 2 /H 2 O ratio in C/2004 Q2 is as lower as Jupiter Family comets. However, mixing ratios of other molecules in C/2004 Q2 are similar to typical Oort Cloud comets. C/2004 Q2 might be the intermediate type between Oort Cloud and Jupiter Family comets. To investigate the formation conditions of such intermediate type comet, we focused on the (C 2 H 2 +C 2 H 6 )/H 2 O ratios and C 2 H 6 /(C 2 H 6 +C 2 H 2 ) ratios in comets from the viewpoint of conversion from C 2 H 2 to C 2 H 6 in the precometary ices. We found that (C 2 H 2 +C 2 H 6 )/H 2 O ratio in C/2004 Q2 is lower than the ratio in typical Oort Cloud comets while C 2 H 6 /(C 2 H 6 +C 2 H 2 ) ratio in C/2004 Q2 is consistent with the ratio of the typical Oort Cloud comets and Jupiter family comets. If we assume that the cometary volatiles such as H 2 O, CH 4 , and C 2 H 2 formed similar environment, the C 2 H 6 /(C 2 H 6 +C 2 H 2 ) ratio might not be sensitive in the temperature range where hydrogen-addition reactions occurred and cometesimals formed (∼30 K). We employed the dynamical-evolutional model and the chemical-evolutional model to determine the formation region of C/2004 Q2 more precisely. We found that comet C/2004 Q2 might have formed in relatively inner region of the solar nebula than the typical Oort Cloud comet (but slightly further than 5 AU from the proto-Sun).

Herbig-haro objects and mid-infrared outflows in the VELA C molecular cloud

International Nuclear Information System (INIS)

Zhang, Miaomiao; Wang, Hongchi; Henning, Thomas

2014-01-01

We have performed a deep [S II] λλ6717/6731 wide field Herbig-Haro (HH) object survey toward the Vela C molecular cloud with a sky coverage of about 2 deg 2 . In total, 18 new HH objects, HH 1090-1107, are discovered and the two previously known HH objects, HH 73-74, are also detected in our [S II] images. We also present an investigation of mid-infrared outflows in the Vela C molecular cloud using the Wide-field Infrared Survey Explorer images taken from AllWISE data release. Using the method suggested by Zhang and Wang, 11 extended green objects (EGOs) are identified to be the mid-infrared outflows, including 6 new mid-infrared outflows that have not been detected previously at other wavelengths and 5 mid-infrared counterparts of the HH objects detected in this work. Using the AllWISE Source Catalog and the source classification scheme suggested by Koenig et al., we have identified 56 young stellar object (YSO) candidates in the Vela C molecular cloud. The possible driving sources of the HH objects and EGOs are discussed based on the morphology of HH objects and EGOs and the locations of HH objects, EGOs and YSO candidates. Finally we associate 12 HH objects and 5 EGOs with 10 YSOs and YSO candidates. The median length of the outflows in Vela C is 0.35 pc and the outflows seem to be oriented randomly.

Cloud object store for checkpoints of high performance computing applications using decoupling middleware

Science.gov (United States)

Bent, John M.; Faibish, Sorin; Grider, Gary

2016-04-19

Cloud object storage is enabled for checkpoints of high performance computing applications using a middleware process. A plurality of files, such as checkpoint files, generated by a plurality of processes in a parallel computing system are stored by obtaining said plurality of files from said parallel computing system; converting said plurality of files to objects using a log structured file system middleware process; and providing said objects for storage in a cloud object storage system. The plurality of processes may run, for example, on a plurality of compute nodes. The log structured file system middleware process may be embodied, for example, as a Parallel Log-Structured File System (PLFS). The log structured file system middleware process optionally executes on a burst buffer node.

The "cholera cloud" in the nineteenth-century "British World": history of an object-without-an-essence.

Science.gov (United States)

Mukharji, Projit Bihari

2012-01-01

The "cholera cloud" is one of the most persistent presences in the archives of nineteenth-century cholera in the "British World." Yet it has seldom received anything more than a passing acknowledgment from historians of cholera. Tracing the history of the cholera cloud as an object promises to open up a new dimension of the historically contingent experience of cholera, as well as make a significant contribution to the emergent literature on "thing theory." By conceptualizing the cholera cloud as an object-without-an-essence, this article demonstrates how global cholera pandemics in the nineteenth century produced globalized objects in which a near-universal recognizability and an utterly context-specific set of meanings, visions, and realities could ironically cohabit.

Cloud object store for archive storage of high performance computing data using decoupling middleware

Science.gov (United States)

Bent, John M.; Faibish, Sorin; Grider, Gary

2015-06-30

Cloud object storage is enabled for archived data, such as checkpoints and results, of high performance computing applications using a middleware process. A plurality of archived files, such as checkpoint files and results, generated by a plurality of processes in a parallel computing system are stored by obtaining the plurality of archived files from the parallel computing system; converting the plurality of archived files to objects using a log structured file system middleware process; and providing the objects for storage in a cloud object storage system. The plurality of processes may run, for example, on a plurality of compute nodes. The log structured file system middleware process may be embodied, for example, as a Parallel Log-Structured File System (PLFS). The log structured file system middleware process optionally executes on a burst buffer node.

A Hybrid Metaheuristic for Multi-Objective Scientific Workflow Scheduling in a Cloud Environment

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Nazia Anwar

2018-03-01

Full Text Available Cloud computing has emerged as a high-performance computing environment with a large pool of abstracted, virtualized, flexible, and on-demand resources and services. Scheduling of scientific workflows in a distributed environment is a well-known NP-complete problem and therefore intractable with exact solutions. It becomes even more challenging in the cloud computing platform due to its dynamic and heterogeneous nature. The aim of this study is to optimize multi-objective scheduling of scientific workflows in a cloud computing environment based on the proposed metaheuristic-based algorithm, Hybrid Bio-inspired Metaheuristic for Multi-objective Optimization (HBMMO. The strong global exploration ability of the nature-inspired metaheuristic Symbiotic Organisms Search (SOS is enhanced by involving an efficient list-scheduling heuristic, Predict Earliest Finish Time (PEFT, in the proposed algorithm to obtain better convergence and diversity of the approximate Pareto front in terms of reduced makespan, minimized cost, and efficient load balance of the Virtual Machines (VMs. The experiments using different scientific workflow applications highlight the effectiveness, practicality, and better performance of the proposed algorithm.

Information Recovery Algorithm for Ground Objects in Thin Cloud Images by Fusing Guide Filter and Transfer Learning

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HU Gensheng

2018-03-01

Full Text Available Ground object information of remote sensing images covered with thin clouds is obscure. An information recovery algorithm for ground objects in thin cloud images is proposed by fusing guide filter and transfer learning. Firstly, multi-resolution decomposition of thin cloud target images and cloud-free guidance images is performed by using multi-directional nonsubsampled dual-tree complex wavelet transform. Then the decomposed low frequency subbands are processed by using support vector guided filter and transfer learning respectively. The decomposed high frequency subbands are enhanced by using modified Laine enhancement function. The low frequency subbands output by guided filter and those predicted by transfer learning model are fused by the method of selection and weighting based on regional energy. Finally, the enhanced high frequency subbands and the fused low frequency subbands are reconstructed by using inverse multi-directional nonsubsampled dual-tree complex wavelet transform to obtain the ground object information recovery images. Experimental results of Landsat-8 OLI multispectral images show that, support vector guided filter can effectively preserve the detail information of the target images, domain adaptive transfer learning can effectively extend the range of available multi-source and multi-temporal remote sensing images, and good effects for ground object information recover are obtained by fusing guide filter and transfer learning to remove thin cloud on the remote sensing images.

Why is Interstellar Object 1I/2017 U1 (`Oumuamua) Rocky, Tumbling and Possibly Very Prolate?

Science.gov (United States)

Katz, J. I.

2018-05-01

The recently discovered first interstellar object 1I/2017 U1 (`Oumuamua) has brightness that varies by a factor of 10, a range greater than that of any Solar System asteroid, a spectrum characteristic of Type D asteroids, and no evidence of evaporating volatiles, contrary to expectation for exo-Oort clouds. `Oumuamua is possibly the first example of the proposed "Jurads", objects depleted in volatiles and ejected from planetary systems during the post-main sequence evolution of their parent stars. I suggest that heating by the star's giant stage fluidized a precursor object as well as driving off any volatiles, causing it to assume the Jacobi ellipsoidal shape of a self-gravitating incompressible liquid. The collision that produced the inferred tumbling motion may have occurred thousands of years after the formation of 1I/2017 U1 `Oumuamua. Jacobi ellipsoids have a unique relation among rotation rate, density and axial ratio. The inferred axial ratio ⪆ 5 suggests a lower bound on the density of 1.6 g/cm3, apparently excluding an icy interior unless it is almost entirely frozen CO2. `Oumuamua may be related to accreting objects that pollute white dwarf atmospheres and that may make Soft Gamma Repeaters.

Roadside Multiple Objects Extraction from Mobile Laser Scanning Point Cloud Based on DBN

Directory of Open Access Journals (Sweden)

LUO Haifeng

2018-02-01

Full Text Available This paper proposed an novel algorithm for exploring deep belief network (DBN architectures to extract and recognize roadside facilities (trees,cars and traffic poles from mobile laser scanning (MLS point cloud.The proposed methods firstly partitioned the raw MLS point cloud into blocks and then removed the ground and building points.In order to partition the off-ground objects into individual objects,off-ground points were organized into an Octree structure and clustered into candidate objects based on connected component.To improve segmentation performance on clusters containing overlapped objects,a refining processing using a voxel-based normalized cut was then implemented.In addition,multi-view features descriptor was generated for each independent roadside facilities based on binary images.Finally,a deep belief network (DBN was trained to extract trees,cars and traffic pole objects.Experiments are undertaken to evaluate the validities of the proposed method with two datasets acquired by Lynx Mobile Mapper System.The precision of trees,cars and traffic poles objects extraction results respectively was 97.31%,97.79% and 92.78%.The recall was 98.30%,98.75% and 96.77% respectively.The quality is 95.70%,93.81% and 90.00%.And the F1 measure was 97.80%,96.81% and 94.73%.

Environmental Impact Specification for Direct Space Weathering of Kuiper Belt and Oort Cloud Objects

Science.gov (United States)

Cooper, John F.

2010-01-01

The Direct Space Weathering Project of NASA's Outer Planets Research Program addresses specification of the plasma and energetic particle environments for irradiation and surface chemical processing of icy bodies in the outer solar system and the local interstellar medium. Knowledge of the radiation environments is being expanded by ongoing penetration of the twin Voyager spacecraft into the heliosheath boundary region of the outer heliosphere and expected emergence within the next decade into the very local interstellar medium. The Voyager measurements are being supplemented by remote sensing from Earth orbit of energetic neutral atom emission from this boundary region by NASA's Interstellar Boundary Explorer (IBEX). Although the Voyagers long ago passed the region of the Classical Kuiper Belt, the New Horizons spacecraft will encounter Pluto in 2015 and thereafter explore one or more KBOs, meanwhile providing updated measurements of the heliospheric radiation environment in this region. Modeling of ion transport within the heliosphere allows specification of time-integrated irradiation effects while the combination of Voyager and IBEX data supports projection of the in-situ measurements into interstellar space beyond the heliosheath. Transformation of model ion flux distributions into surface sputtering and volume ionization profiles provides a multi-layer perspective for space weathering impact on the affected icy bodies and may account for some aspects of color and compositional diversity. Other important related factors may include surface erosion and gardening by meteoritic impacts and surface renewal by cryovolcanism. Chemical products of space weathering may contribute to energy resources for the latter.

THE PECULIAR PHOTOMETRIC PROPERTIES OF 2010 WG9: A SLOWLY ROTATING TRANS-NEPTUNIAN OBJECT FROM THE OORT CLOUD

Energy Technology Data Exchange (ETDEWEB)

Rabinowitz, David; Schwamb, Megan E.; Hadjiyska, Elena [Center for Astronomy and Astrophysics, Yale University, New Haven, CT (United States); Tourtellotte, Suzanne [Astronomy Department, Yale University, New Haven, CT (United States); Rojo, Patricio [Department of Astronomy, University of Chile, Santiago (Chile)

2013-07-01

We present long-term BVRI observations of 2010 WG9, an {approx}100 km diameter trans-Neptunian object (TNO) with an extremely high inclination of 70 Degree-Sign discovered by the La Silla-QUEST southern sky survey. Most of the observations were obtained with ANDICAM on the SMARTS 1.3 m at Cerro Tololo, Chile from 2010 December to 2012 November. Additional observations were made with EFOSC2 on the 3.5 m NTT telescope of the European Southern Observatory at La Silla, Chile in 2011 February. The observations reveal a sinusoidal light curve with amplitude 0.14 mag and period 5.4955 {+-} 0.0025 days, which is likely half the true rotation period. Such long rotation periods have previously been observed only for tidally evolved binary TNOs, suggesting that 2010 WG9 may be such a system. We predict a nominal separation of at least 790 km, resolvable with the Hubble Space Telescope and ground-based systems. We measure B - R = 1.318 {+-} 0.029 and V - R = 0.520 {+-} 0.018, consistent with the colors of modestly red Centaurs and Damocloids. At I-band wavelengths, we observe an unusually large variation of color with rotational phase, with R - I ranging from 0.394 {+-} 0.025 to 0.571 {+-} 0.044. We also measure an absolute R-band absolute magnitude of 7.93 {+-} 0.05 and solar phase coefficient of 0.049 {+-} 0.019 mag deg{sup -1}.

a Two-Step Classification Approach to Distinguishing Similar Objects in Mobile LIDAR Point Clouds

Science.gov (United States)

He, H.; Khoshelham, K.; Fraser, C.

2017-09-01

Nowadays, lidar is widely used in cultural heritage documentation, urban modeling, and driverless car technology for its fast and accurate 3D scanning ability. However, full exploitation of the potential of point cloud data for efficient and automatic object recognition remains elusive. Recently, feature-based methods have become very popular in object recognition on account of their good performance in capturing object details. Compared with global features describing the whole shape of the object, local features recording the fractional details are more discriminative and are applicable for object classes with considerable similarity. In this paper, we propose a two-step classification approach based on point feature histograms and the bag-of-features method for automatic recognition of similar objects in mobile lidar point clouds. Lamp post, street light and traffic sign are grouped as one category in the first-step classification for their inter similarity compared with tree and vehicle. A finer classification of the lamp post, street light and traffic sign based on the result of the first-step classification is implemented in the second step. The proposed two-step classification approach is shown to yield a considerable improvement over the conventional one-step classification approach.

Multi-Objective Approach for Energy-Aware Workflow Scheduling in Cloud Computing Environments

Directory of Open Access Journals (Sweden)

Sonia Yassa

2013-01-01

Full Text Available We address the problem of scheduling workflow applications on heterogeneous computing systems like cloud computing infrastructures. In general, the cloud workflow scheduling is a complex optimization problem which requires considering different criteria so as to meet a large number of QoS (Quality of Service requirements. Traditional research in workflow scheduling mainly focuses on the optimization constrained by time or cost without paying attention to energy consumption. The main contribution of this study is to propose a new approach for multi-objective workflow scheduling in clouds, and present the hybrid PSO algorithm to optimize the scheduling performance. Our method is based on the Dynamic Voltage and Frequency Scaling (DVFS technique to minimize energy consumption. This technique allows processors to operate in different voltage supply levels by sacrificing clock frequencies. This multiple voltage involves a compromise between the quality of schedules and energy. Simulation results on synthetic and real-world scientific applications highlight the robust performance of the proposed approach.

Multi-Objective Approach for Energy-Aware Workflow Scheduling in Cloud Computing Environments

Science.gov (United States)

Kadima, Hubert; Granado, Bertrand

2013-01-01

We address the problem of scheduling workflow applications on heterogeneous computing systems like cloud computing infrastructures. In general, the cloud workflow scheduling is a complex optimization problem which requires considering different criteria so as to meet a large number of QoS (Quality of Service) requirements. Traditional research in workflow scheduling mainly focuses on the optimization constrained by time or cost without paying attention to energy consumption. The main contribution of this study is to propose a new approach for multi-objective workflow scheduling in clouds, and present the hybrid PSO algorithm to optimize the scheduling performance. Our method is based on the Dynamic Voltage and Frequency Scaling (DVFS) technique to minimize energy consumption. This technique allows processors to operate in different voltage supply levels by sacrificing clock frequencies. This multiple voltage involves a compromise between the quality of schedules and energy. Simulation results on synthetic and real-world scientific applications highlight the robust performance of the proposed approach. PMID:24319361

A TWO-STEP CLASSIFICATION APPROACH TO DISTINGUISHING SIMILAR OBJECTS IN MOBILE LIDAR POINT CLOUDS

Directory of Open Access Journals (Sweden)

H. He

2017-09-01

Full Text Available Nowadays, lidar is widely used in cultural heritage documentation, urban modeling, and driverless car technology for its fast and accurate 3D scanning ability. However, full exploitation of the potential of point cloud data for efficient and automatic object recognition remains elusive. Recently, feature-based methods have become very popular in object recognition on account of their good performance in capturing object details. Compared with global features describing the whole shape of the object, local features recording the fractional details are more discriminative and are applicable for object classes with considerable similarity. In this paper, we propose a two-step classification approach based on point feature histograms and the bag-of-features method for automatic recognition of similar objects in mobile lidar point clouds. Lamp post, street light and traffic sign are grouped as one category in the first-step classification for their inter similarity compared with tree and vehicle. A finer classification of the lamp post, street light and traffic sign based on the result of the first-step classification is implemented in the second step. The proposed two-step classification approach is shown to yield a considerable improvement over the conventional one-step classification approach.

A Multi-Objective Compounded Local Mobile Cloud Architecture Using Priority Queues to Process Multiple Jobs.

Science.gov (United States)

Wei, Xiaohui; Sun, Bingyi; Cui, Jiaxu; Xu, Gaochao

2016-01-01

As a result of the greatly increased use of mobile devices, the disadvantages of portable devices have gradually begun to emerge. To solve these problems, the use of mobile cloud computing assisted by cloud data centers has been proposed. However, cloud data centers are always very far from the mobile requesters. In this paper, we propose an improved multi-objective local mobile cloud model: Compounded Local Mobile Cloud Architecture with Dynamic Priority Queues (LMCpri). This new architecture could briefly store jobs that arrive simultaneously at the cloudlet in different priority positions according to the result of auction processing, and then execute partitioning tasks on capable helpers. In the Scheduling Module, NSGA-II is employed as the scheduling algorithm to shorten processing time and decrease requester cost relative to PSO and sequential scheduling. The simulation results show that the number of iteration times that is defined to 30 is the best choice of the system. In addition, comparing with LMCque, LMCpri is able to effectively accommodate a requester who would like his job to be executed in advance and shorten execution time. Finally, we make a comparing experiment between LMCpri and cloud assisting architecture, and the results reveal that LMCpri presents a better performance advantage than cloud assisting architecture.

A Multi-Objective Compounded Local Mobile Cloud Architecture Using Priority Queues to Process Multiple Jobs.

Directory of Open Access Journals (Sweden)

Xiaohui Wei

Full Text Available As a result of the greatly increased use of mobile devices, the disadvantages of portable devices have gradually begun to emerge. To solve these problems, the use of mobile cloud computing assisted by cloud data centers has been proposed. However, cloud data centers are always very far from the mobile requesters. In this paper, we propose an improved multi-objective local mobile cloud model: Compounded Local Mobile Cloud Architecture with Dynamic Priority Queues (LMCpri. This new architecture could briefly store jobs that arrive simultaneously at the cloudlet in different priority positions according to the result of auction processing, and then execute partitioning tasks on capable helpers. In the Scheduling Module, NSGA-II is employed as the scheduling algorithm to shorten processing time and decrease requester cost relative to PSO and sequential scheduling. The simulation results show that the number of iteration times that is defined to 30 is the best choice of the system. In addition, comparing with LMCque, LMCpri is able to effectively accommodate a requester who would like his job to be executed in advance and shorten execution time. Finally, we make a comparing experiment between LMCpri and cloud assisting architecture, and the results reveal that LMCpri presents a better performance advantage than cloud assisting architecture.

Essentials of cloud computing

CERN Document Server

Chandrasekaran, K

2014-01-01

ForewordPrefaceComputing ParadigmsLearning ObjectivesPreambleHigh-Performance ComputingParallel ComputingDistributed ComputingCluster ComputingGrid ComputingCloud ComputingBiocomputingMobile ComputingQuantum ComputingOptical ComputingNanocomputingNetwork ComputingSummaryReview PointsReview QuestionsFurther ReadingCloud Computing FundamentalsLearning ObjectivesPreambleMotivation for Cloud ComputingThe Need for Cloud ComputingDefining Cloud ComputingNIST Definition of Cloud ComputingCloud Computing Is a ServiceCloud Computing Is a Platform5-4-3 Principles of Cloud computingFive Essential Charact

Cloud Computing and Multi Agent System to improve Learning Object Paradigm

Directory of Open Access Journals (Sweden)

Ana B. Gil

2015-05-01

Full Text Available The paradigm of Learning Object provides Educators and Learners with the ability to access an extensive number of learning resources. To do so, this paradigm provides different technologies and tools, such as federated search platforms and storage repositories, in order to obtain information ubiquitously and on demand. However, the vast amount and variety of educational content, which is distributed among several repositories, and the existence of various and incompatible standards, technologies and interoperability layers among repositories, constitutes a real problem for the expansion of this paradigm. This study presents an agent-based architecture that uses the advantages provided by Cloud Computing platforms to deal with the open issues on the Learning Object paradigm.

A combined spectral and object-based approach to transparent cloud removal in an operational setting for Landsat ETM+

Science.gov (United States)

Watmough, Gary R.; Atkinson, Peter M.; Hutton, Craig W.

2011-04-01

The automated cloud cover assessment (ACCA) algorithm has provided automated estimates of cloud cover for the Landsat ETM+ mission since 2001. However, due to the lack of a band around 1.375 μm, cloud edges and transparent clouds such as cirrus cannot be detected. Use of Landsat ETM+ imagery for terrestrial land analysis is further hampered by the relatively long revisit period due to a nadir only viewing sensor. In this study, the ACCA threshold parameters were altered to minimise omission errors in the cloud masks. Object-based analysis was used to reduce the commission errors from the extended cloud filters. The method resulted in the removal of optically thin cirrus cloud and cloud edges which are often missed by other methods in sub-tropical areas. Although not fully automated, the principles of the method developed here provide an opportunity for using otherwise sub-optimal or completely unusable Landsat ETM+ imagery for operational applications. Where specific images are required for particular research goals the method can be used to remove cloud and transparent cloud helping to reduce bias in subsequent land cover classifications.

Using cloud computing technologies in IP-video surveillance systems with the function of 3d-object modelling

Directory of Open Access Journals (Sweden)

Zhigalov Kirill

2018-01-01

Full Text Available This article is devoted to the integration of cloud technology functions into 3D IP video surveil-lance systems in order to conduct further video Analytics, incoming real-time data, as well as stored video materials on the server in the «cloud». The main attention is devoted to «cloud technologies» usage optimizing the process of recognition of the desired object by increasing the criteria of flexibility and scalability of the system. Transferring image load from the client to the cloud server, to the virtual part of the system. The development of the issues considered in the article in terms of data analysis, which will significantly improve the effectiveness of the implementation of special tasks facing special units.

Observations of Herbig-Haro objects and their surrounding dark clouds

International Nuclear Information System (INIS)

Ho, P.T.P.; Barrett, A.H.

1980-01-01

A survey was conducted toward 29 Herbig-Haro objects in the (J, K) 1, 1lines of NH 3 , followed by mapping of the two strongest sources in the NGC 1333 region and the Serpens region. Herbig-Haro objects are found to be associated with dense [n(H 2 )>5 x 10 3 cm -3 ] neutral material, although these are not found to be the site of on-going star formation. Cloud fragmentation appears to have occurred in the regions mapped. Rotation is present with velocity gradients of 1--2 km s -1 pc -1 . Dynamics and stability against collapse are discussed for these regions. Formation of stars of different spectral types is also discussed. In the case of NGC 1333, NH 3 results are used to constrain existing models of CO emission in the region

Object-Based Coregistration of Terrestrial Photogrammetric and ALS Point Clouds in Forested Areas

Science.gov (United States)

Polewski, P.; Erickson, A.; Yao, W.; Coops, N.; Krzystek, P.; Stilla, U.

2016-06-01

Airborne Laser Scanning (ALS) and terrestrial photogrammetry are methods applicable for mapping forested environments. While ground-based techniques provide valuable information about the forest understory, the measured point clouds are normally expressed in a local coordinate system, whose transformation into a georeferenced system requires additional effort. In contrast, ALS point clouds are usually georeferenced, yet the point density near the ground may be poor under dense overstory conditions. In this work, we propose to combine the strengths of the two data sources by co-registering the respective point clouds, thus enriching the georeferenced ALS point cloud with detailed understory information in a fully automatic manner. Due to markedly different sensor characteristics, coregistration methods which expect a high geometric similarity between keypoints are not suitable in this setting. Instead, our method focuses on the object (tree stem) level. We first calculate approximate stem positions in the terrestrial and ALS point clouds and construct, for each stem, a descriptor which quantifies the 2D and vertical distances to other stem centers (at ground height). Then, the similarities between all descriptor pairs from the two point clouds are calculated, and standard graph maximum matching techniques are employed to compute corresponding stem pairs (tiepoints). Finally, the tiepoint subset yielding the optimal rigid transformation between the terrestrial and ALS coordinate systems is determined. We test our method on simulated tree positions and a plot situated in the northern interior of the Coast Range in western Oregon, USA, using ALS data (76 x 121 m2) and a photogrammetric point cloud (33 x 35 m2) derived from terrestrial photographs taken with a handheld camera. Results on both simulated and real data show that the proposed stem descriptors are discriminative enough to derive good correspondences. Specifically, for the real plot data, 24

Wide-field infrared survey explorer observations of young stellar objects in the Lynds 1509 dark cloud in Auriga

Energy Technology Data Exchange (ETDEWEB)

Liu, Wilson M.; McCollum, Bruce; Fajardo-Acosta, Sergio [Infrared Processing and Analysis Center, California Institute of Technology, MC 100-22, Pasadena, CA 91125 (United States); Padgett, Deborah L. [National Aeronautics and Space Administration, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Terebey, Susan; Angione, John [Department of Physics and Astronomy, California State University, Los Angeles, CA 90032 (United States); Rebull, Luisa M. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Leisawitz, David, E-mail: wliu@ipac.caltech.edu [National Aeronautics and Space Administration, Goddard Space Flight Center, Code 605, Greenbelt, MD 20771 (United States)

2014-06-01

The Wide-Field Infrared Survey Explorer (WISE) has uncovered a striking cluster of young stellar object (YSO) candidates associated with the L1509 dark cloud in Auriga. The WISE observations, at 3.4 μm, 4.6 μm, 12 μm, and 22 μm, show a number of objects with colors consistent with YSOs, and their spectral energy distributions suggest the presence of circumstellar dust emission, including numerous Class I, flat spectrum, and Class II objects. In general, the YSOs in L1509 are much more tightly clustered than YSOs in other dark clouds in the Taurus-Auriga star forming region, with Class I and flat spectrum objects confined to the densest aggregates, and Class II objects more sparsely distributed. We estimate a most probable distance of 485-700 pc, and possibly as far as the previously estimated distance of 2 kpc.

Towards Emulation-as-a-Service: Cloud Services for Versatile Digital Object Access

Directory of Open Access Journals (Sweden)

Dirk von Suchodoletz

2013-06-01

Full Text Available The changing world of IT services opens the chance to more tightly integrate digital long-term preservation into systems, both for commercial and end users. The emergence of cloud offerings re-centralizes services, and end users interact with them remotely through standardized (web-client applications on their various devices. This offers the chance to use partially the same concepts and methods to access obsolete computer environments and allows for more sustainable business processes. In order to provide a large variety of user-friendly remote emulation services, especially in combination with authentic performance and user experience, a distributed system model and architecture is required, suitable to run as a cloud service, allowing for the specialization both of memory institutions and third party service providers.The shift of the usually non-trivial task of the emulation of obsolete software environments from the end user to specialized providers can help to simplify digital preservation and access strategies. Besides offering their users better access to their holdings, libraries and archives may gain new business opportunities to offer services to a third party, such as businesses requiring authentic reproduction of digital objects and processes for legal reasons. This paper discusses cloud concepts as the next logical step for accessing original digital material. Emulation-as-a-Service (EaaS fills the gap between the successful demonstration of emulation strategies as a long term access strategy and it’s perceived availability and usability. EaaS can build upon the ground of research and prototypical implementations of previous projects, and reuse well established remote access technology.In this article we develop requirements and a system model, suitable for a distributed environment. We will discuss the building blocks of the core services as well as requirements regarding access management. Finally, we will try to present a

COMPARATIVE STUDY OF CLOUD COMPUTING AND MOBILE CLOUD COMPUTING

OpenAIRE

Nidhi Rajak*, Diwakar Shukla

2018-01-01

Present era is of Information and Communication Technology (ICT) and there are number of researches are going on Cloud Computing and Mobile Cloud Computing such security issues, data management, load balancing and so on. Cloud computing provides the services to the end user over Internet and the primary objectives of this computing are resource sharing and pooling among the end users. Mobile Cloud Computing is a combination of Cloud Computing and Mobile Computing. Here, data is stored in...

Tracking 3D Moving Objects Based on GPS/IMU Navigation Solution, Laser Scanner Point Cloud and GIS Data

Directory of Open Access Journals (Sweden)

Siavash Hosseinyalamdary

2015-07-01

Full Text Available Monitoring vehicular road traffic is a key component of any autonomous driving platform. Detecting moving objects, and tracking them, is crucial to navigating around objects and predicting their locations and trajectories. Laser sensors provide an excellent observation of the area around vehicles, but the point cloud of objects may be noisy, occluded, and prone to different errors. Consequently, object tracking is an open problem, especially for low-quality point clouds. This paper describes a pipeline to integrate various sensor data and prior information, such as a Geospatial Information System (GIS map, to segment and track moving objects in a scene. We show that even a low-quality GIS map, such as OpenStreetMap (OSM, can improve the tracking accuracy, as well as decrease processing time. A bank of Kalman filters is used to track moving objects in a scene. In addition, we apply non-holonomic constraint to provide a better orientation estimation of moving objects. The results show that moving objects can be correctly detected, and accurately tracked, over time, based on modest quality Light Detection And Ranging (LiDAR data, a coarse GIS map, and a fairly accurate Global Positioning System (GPS and Inertial Measurement Unit (IMU navigation solution.

SU-E-T-628: A Cloud Computing Based Multi-Objective Optimization Method for Inverse Treatment Planning.

Science.gov (United States)

Na, Y; Suh, T; Xing, L

2012-06-01

Multi-objective (MO) plan optimization entails generation of an enormous number of IMRT or VMAT plans constituting the Pareto surface, which presents a computationally challenging task. The purpose of this work is to overcome the hurdle by developing an efficient MO method using emerging cloud computing platform. As a backbone of cloud computing for optimizing inverse treatment planning, Amazon Elastic Compute Cloud with a master node (17.1 GB memory, 2 virtual cores, 420 GB instance storage, 64-bit platform) is used. The master node is able to scale seamlessly a number of working group instances, called workers, based on the user-defined setting account for MO functions in clinical setting. Each worker solved the objective function with an efficient sparse decomposition method. The workers are automatically terminated if there are finished tasks. The optimized plans are archived to the master node to generate the Pareto solution set. Three clinical cases have been planned using the developed MO IMRT and VMAT planning tools to demonstrate the advantages of the proposed method. The target dose coverage and critical structure sparing of plans are comparable obtained using the cloud computing platform are identical to that obtained using desktop PC (Intel Xeon® CPU 2.33GHz, 8GB memory). It is found that the MO planning speeds up the processing of obtaining the Pareto set substantially for both types of plans. The speedup scales approximately linearly with the number of nodes used for computing. With the use of N nodes, the computational time is reduced by the fitting model, 0.2+2.3/N, with r̂2>0.99, on average of the cases making real-time MO planning possible. A cloud computing infrastructure is developed for MO optimization. The algorithm substantially improves the speed of inverse plan optimization. The platform is valuable for both MO planning and future off- or on-line adaptive re-planning. © 2012 American Association of Physicists in Medicine.

SPH simulations of star/planet formation triggered by cloud-cloud collisions

OpenAIRE

Kitsionas, Spyridon; Whitworth, Anthony Peter; Klessen, Ralf S.

2007-01-01

We present results of hydrodynamic simulations of star formation triggered by cloud-cloud collisions. During the early stages of star formation, low-mass objects form by gravitational instabilities in protostellar discs. A number of these low-mass objects are in the sub-stellar mass range, including a few objects of planetary mass. The disc instabilities that lead to the formation of low-mass objects in our simulations are the product of disc-disc interactions and/or interactions between the ...

Molecular clouds in the Carina arm - the largest objects, associated regions of star formation, and the Carina arm in the Galaxy

International Nuclear Information System (INIS)

Grabelsky, D.A.; Cohen, R.S.; Bronfman, L.; Thaddeus, P.

1988-01-01

The Columbia CO survey of the southern Galactic plane is used to identify giant molecular clouds and cloud complexes in the Vela-Carina-Centaurus section of the Galaxy. Twenty-seven giant molecular clouds between l = 270 and 300 deg are catalogued and their heliocentric distances given. In addition, 16 clouds at l greater than 300 deg beyond the solar circle extend the catalog to include the very distant portion of the Carina arm. The most massive clouds in the catalog trace the Carina arm over 23 kpc in the plane of the Galaxy. The average mass of these objects is 1.4 x 10 to the 6th solar, and their average spacing along the arm is 700 pc. The composite distribution projected onto the Galactic plane of the largest molecular clouds in the Carina arm and of similarly massive clouds in the first and second quadrants strongly suggests that the Carina and Sagittarius arms form a single spiral arm about 40 kpc in length wrapping two-thirds of the way around the Galaxy. Descriptions of each cloud, including identification of associated star-forming regions, are presented in an appendix. 76 references

Do Clouds Compute? A Framework for Estimating the Value of Cloud Computing

Science.gov (United States)

Klems, Markus; Nimis, Jens; Tai, Stefan

On-demand provisioning of scalable and reliable compute services, along with a cost model that charges consumers based on actual service usage, has been an objective in distributed computing research and industry for a while. Cloud Computing promises to deliver on this objective: consumers are able to rent infrastructure in the Cloud as needed, deploy applications and store data, and access them via Web protocols on a pay-per-use basis. The acceptance of Cloud Computing, however, depends on the ability for Cloud Computing providers and consumers to implement a model for business value co-creation. Therefore, a systematic approach to measure costs and benefits of Cloud Computing is needed. In this paper, we discuss the need for valuation of Cloud Computing, identify key components, and structure these components in a framework. The framework assists decision makers in estimating Cloud Computing costs and to compare these costs to conventional IT solutions. We demonstrate by means of representative use cases how our framework can be applied to real world scenarios.

A FIRST LOOK AT THE AURIGA-CALIFORNIA GIANT MOLECULAR CLOUD WITH HERSCHEL AND THE CSO: CENSUS OF THE YOUNG STELLAR OBJECTS AND THE DENSE GAS

Energy Technology Data Exchange (ETDEWEB)

Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Fallscheer, Cassandra [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada); Ginsburg, Adam [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-0389 (United States); Terebey, Susan [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Andre, Philippe; Koenyves, Vera [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d' Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Di Francesco, James; Matthews, Brenda C. [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Peterson, Dawn E., E-mail: pmh@astro.as.utexas.edu, E-mail: Cassandra.Fallscheer@nrc-cnrc.gc.ca, E-mail: adam.ginsburg@colorado.edu, E-mail: sterebe@calstatela.edu, E-mail: pandre@cea.fr, E-mail: vera.konyves@cea.fr, E-mail: tbourke@cfa.harvard.edu, E-mail: James.DiFrancesco@nrc-cnrc.gc.ca, E-mail: Brenda.Matthews@nrc-cnrc.gc.ca, E-mail: dpeterson@spacescience.org [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80303 (United States)

2013-02-20

We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1 mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears to be forming far fewer stars. We have tabulated 60 compact 70/160 {mu}m sources that are likely pre-main-sequence objects and correlated those with Spitzer and WISE mid-IR sources. At 1.1 mm, we find 18 cold, compact sources and discuss their properties. The most important result from this part of our study is that we find a modest number of additional compact young objects beyond those identified at shorter wavelengths with Spitzer. We also describe the dust column density and temperature structure derived from our photometric maps. The column density peaks at a few Multiplication-Sign 10{sup 22} cm{sup -2} (N {sub H2}) and is distributed in a clear filamentary structure along which nearly all of the pre-main-sequence objects are found. We compare the young stellar object surface density to the gas column density and find a strong nonlinear correlation between them. The dust temperature in the densest parts of the filaments drops to {approx}10 K from values {approx}14-15 K in the low-density parts of the cloud. We also derive the cumulative mass fraction and probability density function of material in the cloud, which we compare with similar data on other star-forming clouds.

A FIRST LOOK AT THE AURIGA-CALIFORNIA GIANT MOLECULAR CLOUD WITH HERSCHEL AND THE CSO: CENSUS OF THE YOUNG STELLAR OBJECTS AND THE DENSE GAS

International Nuclear Information System (INIS)

Harvey, Paul M.; Fallscheer, Cassandra; Ginsburg, Adam; Terebey, Susan; André, Philippe; Könyves, Vera; Bourke, Tyler L.; Di Francesco, James; Matthews, Brenda C.; Peterson, Dawn E.

2013-01-01

We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1 mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears to be forming far fewer stars. We have tabulated 60 compact 70/160 μm sources that are likely pre-main-sequence objects and correlated those with Spitzer and WISE mid-IR sources. At 1.1 mm, we find 18 cold, compact sources and discuss their properties. The most important result from this part of our study is that we find a modest number of additional compact young objects beyond those identified at shorter wavelengths with Spitzer. We also describe the dust column density and temperature structure derived from our photometric maps. The column density peaks at a few × 10 22 cm –2 (N H2 ) and is distributed in a clear filamentary structure along which nearly all of the pre-main-sequence objects are found. We compare the young stellar object surface density to the gas column density and find a strong nonlinear correlation between them. The dust temperature in the densest parts of the filaments drops to ∼10 K from values ∼14-15 K in the low-density parts of the cloud. We also derive the cumulative mass fraction and probability density function of material in the cloud, which we compare with similar data on other star-forming clouds.

VizieR Online Data Catalog: Stellar encounters with long-period comets (Feng+, 2015)

Science.gov (United States)

Feng, F.; Bailer-Jones, C. A. L.

2016-07-01

We have conducted simulations of the perturbation of the Oort cloud in order to estimate the significance of known encounters in generating long-period comets. We collected the data of stellar encounters from three sources: (Bailer-Jones, 2015, Cat. J/A+A/575/A35, hereafter BJ15), Dybczynski & Berski (2015MNRAS.449.2459D), and Mamajek et al. (2015ApJ...800L..17M). Following BJ15, we use the term 'object' to refer to each encountering star in our catalogue. A specific star may appear more than once but with different data, thus leading to a different object. (1 data file).

Point cloud processing for smart systems

Directory of Open Access Journals (Sweden)

Jaromír Landa

2013-01-01

Full Text Available High population as well as the economical tension emphasises the necessity of effective city management – from land use planning to urban green maintenance. The management effectiveness is based on precise knowledge of the city environment. Point clouds generated by mobile and terrestrial laser scanners provide precise data about objects in the scanner vicinity. From these data pieces the state of the roads, buildings, trees and other objects important for this decision-making process can be obtained. Generally, they can support the idea of “smart” or at least “smarter” cities.Unfortunately the point clouds do not provide this type of information automatically. It has to be extracted. This extraction is done by expert personnel or by object recognition software. As the point clouds can represent large areas (streets or even cities, usage of expert personnel to identify the required objects can be very time-consuming, therefore cost ineffective. Object recognition software allows us to detect and identify required objects semi-automatically or automatically.The first part of the article reviews and analyses the state of current art point cloud object recognition techniques. The following part presents common formats used for point cloud storage and frequently used software tools for point cloud processing. Further, a method for extraction of geospatial information about detected objects is proposed. Therefore, the method can be used not only to recognize the existence and shape of certain objects, but also to retrieve their geospatial properties. These objects can be later directly used in various GIS systems for further analyses.

Detailed Information Security in Cloud Computing

OpenAIRE

Pavel Valerievich Ivonin

2013-01-01

The object of research in this article is technology of public clouds, structure and security system of clouds. Problems of information security in clouds are considered, elements of security system in public clouds are described.

Reply to Boslough et al.: Decades of comet research counter their claims

Czech Academy of Sciences Publication Activity Database

Napier, W. M.; Bunch, T. E.; Kennett, J. P.; Wittke, J. H.; Tankersley, K. B.; Kletetschka, Günther; Howard, G. A.; West, A.

2013-01-01

Roč. 110, č. 45 (2013), E4171-E4171 ISSN 0027-8424 Institutional support: RVO:67985831 Keywords : comet * Oort cloud * impact hazard Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 9.809, year: 2013

BUSINESS INTELLIGENCE IN CLOUD

OpenAIRE

Celina M. Olszak

2014-01-01

. The paper reviews and critiques current research on Business Intelligence (BI) in cloud. This review highlights that organizations face various challenges using BI cloud. The research objectives for this study are a conceptualization of the BI cloud issue, as well as an investigation of some benefits and risks from BI cloud. The study was based mainly on a critical analysis of literature and some reports on BI cloud using. The results of this research can be used by IT and business leaders ...

Origin and development of comets

International Nuclear Information System (INIS)

Kresak, L.

1989-01-01

The comets are the most primitive and probably also the oldest members of the solar system. Comet cores are brittle bodies of an irregular shape and of a size of 1 to 10 km whose main component is ice. Around 130 comets move along short-period paths whose aphelia are concentrated in the area of Jupiter. They are in the last stage of development. About 20 comets have periods of 20 to 200 years and feature higher motion stability. Roughly 180 comets have elliptical orbits of a period exceeding 200 years, 200 comets have parabolic and 120 comets have hyperbolic orbits. The most distant comets form the Oort cloud around the solar system consisting of about one billion comets. Comets originated roughly 4.6 thousand million years ago together with planets, probably inside the Oort cloud. (M.D.). 11 figs

Star formation in the Monoceros OB1 dark cloud

International Nuclear Information System (INIS)

Margulis, M.S.

1987-01-01

A survey of the Monoceros OB1 dark cloud was made for molecular outflows and young stellar objects. In all, nine molecular outflows and thirty far-infrared sources were identified in a portion of the cloud composed of about 3 x 10 4 M of material. Statistical arguments suggest that 90% of the far-infrared sources actually are young stellar objects embedded in the cloud. If the star formation rate in the Mon OB1 cloud is roughly constant with time, then molecular outflows in the cloud should be able to support it against collapse due to gravity. This suggests that the birthrate of outflows in the solar neighborhood is very high. In fact, regardless of considerations of cloud support, the large number of outflows identified in the Mon OB1 cloud and the propensity of the youngest stellar objects in the cloud to be associated with outflows suggest that outflows have a high birthrate in the solar neighborhood and are part of a common stage in early stellar evolution. The young stellar objects identified in the cloud can be fit into a spectral classification system. Also, the outflow phase in early stellar evolution tends to occur at about the time that young stellar objects lose a large fraction of their circumstellar envelopes

Long-term Evolution of the Aerosol Debris Cloud Produced by the 2009 Impact of an Object with Jupiter

Science.gov (United States)

Sanchez-Lavega, Agustin; Orton, G. S.; Hueso, R.; Pérez-Hoyos, S.; Fletcher, L. N.; Garcia-Melendo, E.; Gomez, J. M.; de Pater, I.; Wong, M.; Hammel, H. B.; Yanamandra-Fisher, P.; Simon-Miller, M.; Barrado-Izagirre, N.; Marchis, F.; Mousis, O.; Ortiz, J. L.; Garcia, J.; Cecconi, M.; Clarke, J. T.; Noll, K.; Pedraz, S.; Wesley, A.; McConnel, N.; Kalas, P.; Graham, J.; McKenzie, L.; Reddy, V.; Golisch, W.; Griep, D.; Sears, P.; International Outer PLanet Watch (IOPW)

2010-10-01

We report the evolution of the cloud of aerosols produced in the atmosphere of Jupiter by the impact of an object in 19 July 2009 (Sánchez-Lavega et al., Astrophys. J. Lett, Vol. 715, L155. 2010). This study is based on images obtained with a battery of ground-based telescopes and the Hubble Space Telescope in the visible and in the deep near infrared absorption bands at 2.1-2.3 microns from the impact date to 31 December 2009. The impact cloud expanded zonally from 5000 km (July 19) to 225,000 km (about 180 deg in longitude by 29 October) and it was meridionally localized within a latitude band from -53.5 deg to -61.5 deg. During the first two months it showed a heterogeneous structure with embedded spots of a size of 500 - 1000 km. The cloud was mainly dispersed in longitude by the dominant zonal winds and their meridional shear and, during the initial stages, by the action of local motions perhaps originated by the thermal perturbation produced at the impact site. The tracking of individual spots within the impact cloud showed that the winds increase their eastward velocity with altitude above the tropopause by 5-10 m/s. We found evidence of discrete localized meridional motions in the equatorward direction with speeds of 1 - 2 m/s. Measurements of the cloud reflectivity evolution during the whole period showed that it followed an exponential decrease with a characteristic time of 15 days, shorter than the 45 - 200 days sedimentation time for the small aerosol particles in the stratosphere. A radiative transfer model of the cloud optical depth coupled to an advection model of the cloud dispersion by the wind shears, reproduces this behavior. Acknowledgements: ASL, RH, SPH, NBI are supported by the Spanish MICIIN AYA2009-10701 with FEDER and Grupos Gobierno Vasco IT-464-07.

Uranus, Neptune, Pluto, and the outer solar system

CERN Document Server

Elkins-Tanton, Linda T

2010-01-01

Unlike all the planets closer to the Sun, known since antiquity, the farthest reaches are the discoveries of the modern world. Uranus was discovered in 1781, Neptune in 1846, Pluto in 1930, the Kuiper belt group of objects in 1992, and though the Oort cloud has been theorized since 1950, its first member was found in 2004. The discovery of the outer planets made such an impression on the minds of mankind that they were immortalized in the names of the newly discovered elements: uranium, neptunium, and plutonium, an astonishingly deadly constituent of atomic bombs. Uranus, Neptune, Pluto, and t

YOUNG STELLAR OBJECTS IN THE LARGE MAGELLANIC CLOUD STAR-FORMING REGION N206

International Nuclear Information System (INIS)

Romita, Krista Alexandra; Meixner, M.; Sewilo, M.; Shiao, B.; Carlson, Lynn Redding; Whitney, B.; Babler, B.; Meade, M.; Indebetouw, R.; Hora, J. L.

2010-01-01

We present analysis of the energetic star-forming region Henize 206 (N206) located near the southern edge of the Large Magellanic Cloud (LMC) based on photometric data from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE-LMC; IRAC 3.6, 4.5, 5.8, 8.0 μm and MIPS 24 μm), Infrared Survey Facility near-infrared survey (J, H, K s ), and the Magellanic Clouds Photometric Survey (MCPS UBVI) covering a wavelength range of 0.36-24 μm. Young stellar object (YSO) candidates are identified based upon their location in infrared color-magnitude space and classified by the shapes of their spectral energy distributions in comparison with a pre-computed grid of YSO models. We identify 116 YSO candidates: 102 are well characterized by the YSO models, predominately Stage I, and 14 may be multiple sources or young sources with transition disks. Careful examination of the individual sources and their surrounding environment allows us to identify a factor of ∼14.5 more YSO candidates than have already been identified. The total mass of these well-fit YSO candidates is ∼520 M sun . We calculate a current star formation rate of 0.27 x 10 -1 M sun yr -1 kpc -2 . The distribution of YSO candidates appears to follow shells of neutral material in the interstellar medium.

A Novel Cloud Computing Mapping and Management through Class and Object Hierarchy (CCMMCOH)

OpenAIRE

Naveen Gurjar; Ravindra Gupta

2011-01-01

The role of data analytics increases in several application domains to cope with the large amount of captured data. Cloud computing has become one of the key considerations both in academia and industry. Cheap, seemingly unlimited computing resources that can be allocated almost instantaneously and pay-as-you-go pricing schemes are some of the reasons for the success of Cloud computing .In this paper we discuss few aspects of cloud computing and also there area. We also propose a novel approa...

Infrared studies of two dark clouds

International Nuclear Information System (INIS)

Elias, J.H.

1978-01-01

The IC5146 dark cloud complex was surveyed in the infrared in order to identify and study associated young stellar objects. Most of the objects detected in the survey appears to be field stars, predominantly late-type giants. Three young objects were detected in the survey: the BO star BD + 46 x 3474, the Ae star BD + 46 x 3471, and a previously unidentified object which appear to be a heavily obscured FU Ori star. The properties of the last two objects are examined in detail, and an attempt is made to produce reasonable models for them. It is suggested that FU Ori stars are binaries, and some consequences of this model are described. Photometry of the brighter stars in the IC5146 cluster was used to establish a distance to the cluster of 900 +- 100 pc. A near-infrared survey was also conducted of nearly 18 square degrees of the Ophiuchus dark cloud complex. Additional observations were made of selected objects found in this region, in order to identify and study the young stars associated with the cloud. These observations show that very recent star formation has been largely restricted to a small region no more than a few parsecs in extent at the center of the dark cloud complex. Most of the young stars do not appear to be main sequence stars. At least three of these objects appear to be surrounded by infrared reflection nebulae. Many of the objects studies are background K and M giants which can be used to determine the near-infrared extinction due to the dark cloud

Origin and Evolution of the Cometary Reservoirs

Science.gov (United States)

Dones, Luke; Brasser, Ramon; Kaib, Nathan; Rickman, Hans

2015-12-01

Comets have three known reservoirs: the roughly spherical Oort Cloud (for long-period comets), the flattened Kuiper Belt (for ecliptic comets), and, surprisingly, the asteroid belt (for main-belt comets). Comets in the Oort Cloud were thought to have formed in the region of the giant planets and then placed in quasi-stable orbits at distances of thousands or tens of thousands of AU through the gravitational effects of the planets and the Galaxy. The planets were long assumed to have formed in place. However, the giant planets may have undergone two episodes of migration. The first would have taken place in the first few million years of the Solar System, during or shortly after the formation of the giant planets, when gas was still present in the protoplanetary disk around the Sun. The Grand Tack (Walsh et al. in Nature 475:206-209, 2011) models how this stage of migration could explain the low mass of Mars and deplete, then repopulate the asteroid belt, with outer-belt asteroids originating between, and outside of, the orbits of the giant planets. The second stage of migration would have occurred later (possibly hundreds of millions of years later) due to interactions with a remnant disk of planetesimals, i.e., a massive ancestor of the Kuiper Belt. Safronov (Evolution of the Protoplanetary Cloud and Formation of the Earth and the Planets, 1969) and Fernández and Ip (Icarus 58:109-120, 1984) proposed that the giant planets would have migrated as they interacted with leftover planetesimals; Jupiter would have moved slightly inward, while Saturn and (especially) Uranus and Neptune would have moved outward from the Sun. Malhotra (Nature 365:819-821, 1993) showed that Pluto's orbit in the 3:2 resonance with Neptune was a natural outcome if Neptune captured Pluto into resonance while it migrated outward. Building on this work, Tsiganis et al. (Nature 435:459-461, 2005) proposed the Nice model, in which the giant planets formed closer together than they are now, and

Modeling CO, CO2, and H2O Ice Abundances in the Envelopes of Young Stellar Objects in the Magellanic Clouds

Science.gov (United States)

Pauly, Tyler; Garrod, Robin T.

2018-02-01

Massive young stellar objects (MYSOs) in the Magellanic Clouds show infrared absorption features corresponding to significant abundances of CO, CO2, and H2O ice along the line of sight, with the relative abundances of these ices differing between the Magellanic Clouds and the Milky Way. CO ice is not detected toward sources in the Small Magellanic Cloud, and upper limits put its relative abundance well below sources in the Large Magellanic Cloud and the Milky Way. We use our gas-grain chemical code MAGICKAL, with multiple grain sizes and grain temperatures, and further expand it with a treatment for increased interstellar radiation field intensity to model the elevated dust temperatures observed in the MCs. We also adjust the elemental abundances used in the chemical models, guided by observations of H II regions in these metal-poor satellite galaxies. With a grid of models, we are able to reproduce the relative ice fractions observed in MC MYSOs, indicating that metal depletion and elevated grain temperature are important drivers of the MYSO envelope ice composition. Magellanic Cloud elemental abundances have a subgalactic C/O ratio, increasing H2O ice abundances relative to the other ices; elevated grain temperatures favor CO2 production over H2O and CO. The observed shortfall in CO in the Small Magellanic Cloud can be explained by a combination of reduced carbon abundance and increased grain temperatures. The models indicate that a large variation in radiation field strength is required to match the range of observed LMC abundances. CH3OH abundance is found to be enhanced in low-metallicity models, providing seed material for complex organic molecule formation in the Magellanic Clouds.

Large, cold, and unusual molecular cloud in Monoceros

International Nuclear Information System (INIS)

Maddalena, R.J.; Thaddeus, P.; and Columbia University)

1985-01-01

Observations of the J = 1 → 0 rotational transition of CO near the galactic plane in Monoceros (lroughly-equal216 0 ) reveal a molecular cloud with unusually low peak CO temperatures (T/sub R/ -1 ) typical of much warmer clouds. At the assumed distance of 3 kpc, the cloud is large (250 x 100 pc), has a mass of 7-11 x 10 5 M/sub sun/, and is well removed from the galactic midplane (130 pc). Except for a possible H II region, all the signs of star formation usually shown by clouds of comparable mass are missing. The cloud, unlike cloud complexes of similar size, is a single, continuous object that apparently has not been torn apart by star formation. Clouds with such properties are rare in the Galaxy; only one or two similar objects have been found. We discuss the possibility that the cloud is young and not yet forming stars but will evolve into a typical cloud complex once star formation begins

The structure of the clouds distributed operating system

Science.gov (United States)

Dasgupta, Partha; Leblanc, Richard J., Jr.

1989-01-01

A novel system architecture, based on the object model, is the central structuring concept used in the Clouds distributed operating system. This architecture makes Clouds attractive over a wide class of machines and environments. Clouds is a native operating system, designed and implemented at Georgia Tech. and runs on a set of generated purpose computers connected via a local area network. The system architecture of Clouds is composed of a system-wide global set of persistent (long-lived) virtual address spaces, called objects that contain persistent data and code. The object concept is implemented at the operating system level, thus presenting a single level storage view to the user. Lightweight treads carry computational activity through the code stored in the objects. The persistent objects and threads gives rise to a programming environment composed of shared permanent memory, dispensing with the need for hardware-derived concepts such as the file systems and message systems. Though the hardware may be distributed and may have disks and networks, the Clouds provides the applications with a logically centralized system, based on a shared, structured, single level store. The current design of Clouds uses a minimalist philosophy with respect to both the kernel and the operating system. That is, the kernel and the operating system support a bare minimum of functionality. Clouds also adheres to the concept of separation of policy and mechanism. Most low-level operating system services are implemented above the kernel and most high level services are implemented at the user level. From the measured performance of using the kernel mechanisms, we are able to demonstrate that efficient implementations are feasible for the object model on commercially available hardware. Clouds provides a rich environment for conducting research in distributed systems. Some of the topics addressed in this paper include distributed programming environments, consistency of persistent data

Origin of comets - implications for planetary formation

International Nuclear Information System (INIS)

Weissman, P.R.; Arizona Univ., Tucson)

1985-01-01

Primordial and episodic theories for the origin of comets are discussed. The implications of the former type for the origin of the solar system are considered. Candidate sites for the formation of comets are compared. The possible existence of a massive inner Oort cloud is discussed

Cloud fraction and cloud base measurements from scanning Doppler lidar during WFIP-2

Science.gov (United States)

Bonin, T.; Long, C.; Lantz, K. O.; Choukulkar, A.; Pichugina, Y. L.; McCarty, B.; Banta, R. M.; Brewer, A.; Marquis, M.

2017-12-01

The second Wind Forecast Improvement Project (WFIP-2) consisted of an 18-month field deployment of a variety of instrumentation with the principle objective of validating and improving NWP forecasts for wind energy applications in complex terrain. As a part of the set of instrumentation, several scanning Doppler lidars were installed across the study domain to primarily measure profiles of the mean wind and turbulence at high-resolution within the planetary boundary layer. In addition to these measurements, Doppler lidar observations can be used to directly quantify the cloud fraction and cloud base, since clouds appear as a high backscatter return. These supplementary measurements of clouds can then be used to validate cloud cover and other properties in NWP output. Herein, statistics of the cloud fraction and cloud base height from the duration of WFIP-2 are presented. Additionally, these cloud fraction estimates from Doppler lidar are compared with similar measurements from a Total Sky Imager and Radiative Flux Analysis (RadFlux) retrievals at the Wasco site. During mostly cloudy to overcast conditions, estimates of the cloud radiating temperature from the RadFlux methodology are also compared with Doppler lidar measured cloud base height.

Molecular clouds in Orion and Monoceros

International Nuclear Information System (INIS)

Maddalena, R.J.

1986-01-01

About one-eighth of a well-sampled 850 deg 2 region of Orion and Monoceros, extending from the Taurus dark cloud complex to the CMa OB 1 association, shows emission at the frequency of the J = 1 → 0 transition of CO coming from either local clouds (d 8 from the galactic plane or from more distant objects located within a few degrees of the plane and well outside the solar circle. Local giant molecular clouds associated with Orion A and B have enhanced temperatures and densities near their western edges possibly due to compression of molecular gas by a high pressure region created by the cumulative effects of ∼10 supernovae that occurred in the Orion OB association. Another giant molecular cloud found to be associated with Mon R2 may be related to the Orion clouds. Two filamentary clouds (one possible 200 pc long but only 3-10 pc wide) were found that may represent a new class of object; magnetic fields probably play a role in confining these filaments. An expanding ring of clouds concentric with the H II region S 264 and its ionizing 08 star λ Ori was also investigated, and a possible evolutionary sequence for the ring is given in detail: the clouds probably constitute fragments of the original cloud from which λ Ori formed, the gas pressure of the H II region and the rocket effect having disrupted the cloud and accelerated the fragments to their present velocities

The algorithm to generate color point-cloud with the registration between panoramic image and laser point-cloud

International Nuclear Information System (INIS)

Zeng, Fanyang; Zhong, Ruofei

2014-01-01

Laser point cloud contains only intensity information and it is necessary for visual interpretation to obtain color information from other sensor. Cameras can provide texture, color, and other information of the corresponding object. Points with color information of corresponding pixels in digital images can be used to generate color point-cloud and is conducive to the visualization, classification and modeling of point-cloud. Different types of digital cameras are used in different Mobile Measurement Systems (MMS).the principles and processes for generating color point-cloud in different systems are not the same. The most prominent feature of the panoramic images is the field of 360 degrees view angle in the horizontal direction, to obtain the image information around the camera as much as possible. In this paper, we introduce a method to generate color point-cloud with panoramic image and laser point-cloud, and deduce the equation of the correspondence between points in panoramic images and laser point-clouds. The fusion of panoramic image and laser point-cloud is according to the collinear principle of three points (the center of the omnidirectional multi-camera system, the image point on the sphere, the object point). The experimental results show that the proposed algorithm and formulae in this paper are correct

Augmented reality system using lidar point cloud data for displaying dimensional information of objects on mobile phones

OpenAIRE

Gupta, S.; Lohani, B.

2014-01-01

Mobile augmented reality system is the next generation technology to visualise 3D real world intelligently. The technology is expanding at a fast pace to upgrade the status of a smart phone to an intelligent device. The research problem identified and presented in the current work is to view actual dimensions of various objects that are captured by a smart phone in real time. The methodology proposed first establishes correspondence between LiDAR point cloud, that are stored in a ser...

2060 Chiron - Colorimetry and cometary behavior

Science.gov (United States)

Hartmann, William K.; Tholen, David J.; Meech, Karen J.; Cruikshank, Dale P.

1990-01-01

Ambiguities concerning the fit of the 2060 Chiron's visible spectrum to its IR spectrum have been resolved by resort to VRIJHK colorimetry obtained in 1988, which also confirms the neutrality of Chiron's taxonomic class C spectrum and indicates that Chiron has anomalously brightened since 1980-1983. This brightening, and one reported in 1978, are consistent with the hypothesis that Chiron sporadically undergoes weak cometary outbursts similar to those of comet P/Schwassmann-Wachmann 1; Chiron is further speculated to be an ice-rich object darkened by C-class carbonaceous soil, and may have been scattered from the Oort cloud in recent solar system history.

Determination of clouds in MSG data for the validation of clouds in a regional climate model

OpenAIRE

Huckle, Roger

2009-01-01

Regional climate models (e.g. CLM) can help to asses the influence of the antropogenic climate change on the different regions of the earth. Validation of these models is very important. Satellite data are of great benefit, as data on a global scale and high temporal resolution is available. In this thesis a cloud detection and object based cloud classification for Meteosat Second Generation (MSG) was developed and used to validate CLM clouds. Results show sometimes too many clouds in the CLM.

Formation of massive, dense cores by cloud-cloud collisions

Science.gov (United States)

Takahira, Ken; Shima, Kazuhiro; Habe, Asao; Tasker, Elizabeth J.

2018-05-01

We performed sub-parsec (˜ 0.014 pc) scale simulations of cloud-cloud collisions of two idealized turbulent molecular clouds (MCs) with different masses in the range of (0.76-2.67) × 104 M_{⊙} and with collision speeds of 5-30 km s-1. Those parameters are larger than in Takahira, Tasker, and Habe (2014, ApJ, 792, 63), in which study the colliding system showed a partial gaseous arc morphology that supports the NANTEN observations of objects indicated to be colliding MCs using numerical simulations. Gas clumps with density greater than 10-20 g cm-3 were identified as pre-stellar cores and tracked through the simulation to investigate the effects of the mass of colliding clouds and the collision speeds on the resulting core population. Our results demonstrate that the smaller cloud property is more important for the results of cloud-cloud collisions. The mass function of formed cores can be approximated by a power-law relation with an index γ = -1.6 in slower cloud-cloud collisions (v ˜ 5 km s-1), and is in good agreement with observation of MCs. A faster relative speed increases the number of cores formed in the early stage of collisions and shortens the gas accretion phase of cores in the shocked region, leading to the suppression of core growth. The bending point appears in the high-mass part of the core mass function and the bending point mass decreases with increase in collision speed for the same combination of colliding clouds. The higher-mass part of the core mass function than the bending point mass can be approximated by a power law with γ = -2-3 that is similar to the power index of the massive part of the observed stellar initial mass function. We discuss implications of our results for the massive-star formation in our Galaxy.

Resource-Aware Load Balancing Scheme using Multi-objective Optimization in Cloud Computing

OpenAIRE

Kavita Rana; Vikas Zandu

2016-01-01

Cloud computing is a service based, on-demand, pay per use model consisting of an interconnected and virtualizes resources delivered over internet. In cloud computing, usually there are number of jobs that need to be executed with the available resources to achieve optimal performance, least possible total time for completion, shortest response time, and efficient utilization of resources etc. Hence, job scheduling is the most important concern that aims to ensure that use’s requirement are ...

Analysis on Cloud Computing Database in Cloud Environment – Concept and Adoption Paradigm

Directory of Open Access Journals (Sweden)

Elena-Geanina ULARU

2012-08-01

Full Text Available With the development of the Internet’s new technical functionalities, new concepts have started to take shape. These concepts have an important role especially in the development of corporate IT. Such a concept is „the Cloud”. Various marketing campaigns have started to focus on the Cloud and began to promote it in different but confusing ways. This campaigns do little, to explain what cloud computing is and why it is becoming increasingly necessary. The lack of understanding in this new technology generates a lack of knowledge in business cloud adoption regarding database and also application. Only by focusing on the business processes and objectives an enterprise can achieve the full benefits of the cloud and mitigate the potential risks. In this article we create our own complete definition of the cloud and we analyze the essential aspects of cloud adoption for a banking financial reporting application.

Cloud detection method for Chinese moderate high resolution satellite imagery (Conference Presentation)

Science.gov (United States)

Zhong, Bo; Chen, Wuhan; Wu, Shanlong; Liu, Qinhuo

2016-10-01

Cloud detection of satellite imagery is very important for quantitative remote sensing research and remote sensing applications. However, many satellite sensors don't have enough bands for a quick, accurate, and simple detection of clouds. Particularly, the newly launched moderate to high spatial resolution satellite sensors of China, such as the charge-coupled device on-board the Chinese Huan Jing 1 (HJ-1/CCD) and the wide field of view (WFV) sensor on-board the Gao Fen 1 (GF-1), only have four available bands including blue, green, red, and near infrared bands, which are far from the requirements of most could detection methods. In order to solve this problem, an improved and automated cloud detection method for Chinese satellite sensors called OCM (Object oriented Cloud and cloud-shadow Matching method) is presented in this paper. It firstly modified the Automatic Cloud Cover Assessment (ACCA) method, which was developed for Landsat-7 data, to get an initial cloud map. The modified ACCA method is mainly based on threshold and different threshold setting produces different cloud map. Subsequently, a strict threshold is used to produce a cloud map with high confidence and large amount of cloud omission and a loose threshold is used to produce a cloud map with low confidence and large amount of commission. Secondly, a corresponding cloud-shadow map is also produced using the threshold of near-infrared band. Thirdly, the cloud maps and cloud-shadow map are transferred to cloud objects and cloud-shadow objects. Cloud and cloud-shadow are usually in pairs; consequently, the final cloud and cloud-shadow maps are made based on the relationship between cloud and cloud-shadow objects. OCM method was tested using almost 200 HJ-1/CCD images across China and the overall accuracy of cloud detection is close to 90%.

Molecular clouds near supernova remnants

International Nuclear Information System (INIS)

Wootten, H.A.

1978-01-01

The physical properties of molecular clouds near supernova remnants were investigated. Various properties of the structure and kinematics of these clouds are used to establish their physical association with well-known remmnants. An infrared survey of the most massive clouds revealed embedded objects, probably stars whose formation was induced by the supernova blast wave. In order to understand the relationship between these and other molecular clouds, a control group of clouds was also observed. Excitation models for dense regions of all the clouds are constructed to evaluate molecular abundances in these regions. Those clouds that have embedded stars have lower molecular abundances than the clouds that do not. A cloud near the W28 supernova remnant also has low abundances. Molecular abundances are used to measure an important parameter, the electron density, which is not directly observable. In some clouds extensive deuterium fractionation is observed which confirms electron density measurements in those clouds. Where large deuterium fractionation is observed, the ionization rate in the cloud interior can also be measured. The electron density and ionization rate in the cloud near W28 are higher than in most clouds. The molecular abundances and electron densities are functions of the chemical and dynamical state of evolution of the cloud. Those clouds with lowest abundances are probably the youngest clouds. As low-abundance clouds, some clouds near supernova remnants may have been recently swept from the local interstellar material. Supernova remnants provide sites for star formation in ambient clouds by compressing them, and they sweep new clouds from more diffuse local matter

A cloud shadow detection method combined with cloud height iteration and spectral analysis for Landsat 8 OLI data

Science.gov (United States)

Sun, Lin; Liu, Xinyan; Yang, Yikun; Chen, TingTing; Wang, Quan; Zhou, Xueying

2018-04-01

Although enhanced over prior Landsat instruments, Landsat 8 OLI can obtain very high cloud detection precisions, but for the detection of cloud shadows, it still faces great challenges. Geometry-based cloud shadow detection methods are considered the most effective and are being improved constantly. The Function of Mask (Fmask) cloud shadow detection method is one of the most representative geometry-based methods that has been used for cloud shadow detection with Landsat 8 OLI. However, the Fmask method estimates cloud height employing fixed temperature rates, which are highly uncertain, and errors of large area cloud shadow detection can be caused by errors in estimations of cloud height. This article improves the geometry-based cloud shadow detection method for Landsat OLI from the following two aspects. (1) Cloud height no longer depends on the brightness temperature of the thermal infrared band but uses a possible dynamic range from 200 m to 12,000 m. In this case, cloud shadow is not a specific location but a possible range. Further analysis was carried out in the possible range based on the spectrum to determine cloud shadow location. This effectively avoids the cloud shadow leakage caused by the error in the height determination of a cloud. (2) Object-based and pixel spectral analyses are combined to detect cloud shadows, which can realize cloud shadow detection from two aspects of target scale and pixel scale. Based on the analysis of the spectral differences between the cloud shadow and typical ground objects, the best cloud shadow detection bands of Landsat 8 OLI were determined. The combined use of spectrum and shape can effectively improve the detection precision of cloud shadows produced by thin clouds. Several cloud shadow detection experiments were carried out, and the results were verified by the results of artificial recognition. The results of these experiments indicated that this method can identify cloud shadows in different regions with correct

Object-Based Point Cloud Analysis of Full-Waveform Airborne Laser Scanning Data for Urban Vegetation Classification

Directory of Open Access Journals (Sweden)

Norbert Pfeifer

2008-08-01

Full Text Available Airborne laser scanning (ALS is a remote sensing technique well-suited for 3D vegetation mapping and structure characterization because the emitted laser pulses are able to penetrate small gaps in the vegetation canopy. The backscattered echoes from the foliage, woody vegetation, the terrain, and other objects are detected, leading to a cloud of points. Higher echo densities (> 20 echoes/m2 and additional classification variables from full-waveform (FWF ALS data, namely echo amplitude, echo width and information on multiple echoes from one shot, offer new possibilities in classifying the ALS point cloud. Currently FWF sensor information is hardly used for classification purposes. This contribution presents an object-based point cloud analysis (OBPA approach, combining segmentation and classification of the 3D FWF ALS points designed to detect tall vegetation in urban environments. The definition tall vegetation includes trees and shrubs, but excludes grassland and herbage. In the applied procedure FWF ALS echoes are segmented by a seeded region growing procedure. All echoes sorted descending by their surface roughness are used as seed points. Segments are grown based on echo width homogeneity. Next, segment statistics (mean, standard deviation, and coefficient of variation are calculated by aggregating echo features such as amplitude and surface roughness. For classification a rule base is derived automatically from a training area using a statistical classification tree. To demonstrate our method we present data of three sites with around 500,000 echoes each. The accuracy of the classified vegetation segments is evaluated for two independent validation sites. In a point-wise error assessment, where the classification is compared with manually classified 3D points, completeness and correctness better than 90% are reached for the validation sites. In comparison to many other algorithms the proposed 3D point classification works on the original

Augmented reality system using lidar point cloud data for displaying dimensional information of objects on mobile phones

Science.gov (United States)

Gupta, S.; Lohani, B.

2014-05-01

Mobile augmented reality system is the next generation technology to visualise 3D real world intelligently. The technology is expanding at a fast pace to upgrade the status of a smart phone to an intelligent device. The research problem identified and presented in the current work is to view actual dimensions of various objects that are captured by a smart phone in real time. The methodology proposed first establishes correspondence between LiDAR point cloud, that are stored in a server, and the image t hat is captured by a mobile. This correspondence is established using the exterior and interior orientation parameters of the mobile camera and the coordinates of LiDAR data points which lie in the viewshed of the mobile camera. A pseudo intensity image is generated using LiDAR points and their intensity. Mobile image and pseudo intensity image are then registered using image registration method SIFT thereby generating a pipeline to locate a point in point cloud corresponding to a point (pixel) on the mobile image. The second part of the method uses point cloud data for computing dimensional information corresponding to the pairs of points selected on mobile image and fetch the dimensions on top of the image. This paper describes all steps of the proposed method. The paper uses an experimental setup to mimic the mobile phone and server system and presents some initial but encouraging results

Giant molecular cloud scaling relations: the role of the cloud definition

Science.gov (United States)

Khoperskov, S. A.; Vasiliev, E. O.; Ladeyschikov, D. A.; Sobolev, A. M.; Khoperskov, A. V.

2016-01-01

We investigate the physical properties of molecular clouds in disc galaxies with different morphologies: a galaxy without prominent structure, a spiral barred galaxy and a galaxy with flocculent structure. Our N-body/hydrodynamical simulations take into account non-equilibrium H2 and CO chemical kinetics, self-gravity, star formation and feedback processes. For the simulated galaxies, the scaling relations of giant molecular clouds, or so-called Larson's relations, are studied for two types of cloud definition (or extraction method): the first is based on total column density position-position (PP) data sets and the second is indicated by the CO (1-0) line emission used in position-position-velocity (PPV) data. We find that the cloud populations obtained using both cloud extraction methods generally have similar physical parameters, except that for the CO data the mass spectrum of clouds has a tail with low-mass objects M ˜ 103-104 M⊙. Owing toa varying column density threshold, the power-law indices in the scaling relations are significantly changed. In contrast, the relations are invariant to the CO brightness temperature threshold. Finally, we find that the mass spectra of clouds for PPV data are almost insensitive to the galactic morphology, whereas the spectra for PP data demonstrate significant variation.

Cloud Services from Consumer Standpoint

OpenAIRE

Koski, Jori

2016-01-01

The objective of this thesis is to clarify the use of cloud services and how they are used in practice. This thesis will first cover the history of cloud computing. At the early days of computing, services have been stored on servers locally and could be accessed through direct connections. After this, services have been on the users’ personal computers. Nowadays, services are stored in the cloud. This research paper focuses on four sub topics: communication services, healthcare se...

Research on cloud computing solutions

Directory of Open Access Journals (Sweden)

Liudvikas Kaklauskas

2015-07-01

Full Text Available Cloud computing can be defined as a new style of computing in which dynamically scala-ble and often virtualized resources are provided as a services over the Internet. Advantages of the cloud computing technology include cost savings, high availability, and easy scalability. Voas and Zhang adapted six phases of computing paradigms, from dummy termi-nals/mainframes, to PCs, networking computing, to grid and cloud computing. There are four types of cloud computing: public cloud, private cloud, hybrid cloud and community. The most common and well-known deployment model is Public Cloud. A Private Cloud is suited for sensitive data, where the customer is dependent on a certain degree of security.According to the different types of services offered, cloud computing can be considered to consist of three layers (services models: IaaS (infrastructure as a service, PaaS (platform as a service, SaaS (software as a service. Main cloud computing solutions: web applications, data hosting, virtualization, database clusters and terminal services. The advantage of cloud com-puting is the ability to virtualize and share resources among different applications with the objective for better server utilization and without a clustering solution, a service may fail at the moment the server crashes.DOI: 10.15181/csat.v2i2.914

A YOUNG PLANETARY-MASS OBJECT IN THE ρ OPH CLOUD CORE

International Nuclear Information System (INIS)

Marsh, Kenneth A.; Kirkpatrick, J. Davy; Plavchan, Peter

2010-01-01

We report the discovery of a young planetary-mass brown dwarf in the ρ Oph cloud core. The object was identified as such with the aid of a 1.5-2.4 μm low-resolution spectrum obtained using the NIRC instrument on the Keck I telescope. Based on the COND model, the observed spectrum is consistent with a reddened (A V ∼ 15-16) brown dwarf whose effective temperature is in the range 1200-1800 K. For an assumed age of 1 Myr, comparison with isochrones further constrains the temperature to ∼1400 K and suggests a mass of ∼2-3 Jupiter masses. The inferred temperature is suggestive of an early T spectral type, which is supported by spectral morphology consistent with weak methane absorption. Based on its inferred distance (∼100 pc) and the presence of overlying visual absorption, it is very likely to be a ρ Oph cluster member. In addition, given the estimated spectral type, it may be the youngest and least massive T dwarf found so far. Its existence suggests that the initial mass function for the ρ Oph star-forming region extends well into the planetary-mass regime.

Astrophysical life extinctions what killed the dinosaurs?

CERN Document Server

Dar, Arnon

1999-01-01

Geological records indicate that the exponential diversification of marine and continental life on Earth in the past 500 My was interrupted by many life extinctions. They also indicate that the major mass extinctions were correlated in time with large meteoritic impacts, gigantic volcanic eruptions, sea regressions and drastic changes in global climate. Some of these catastrophes coincided in time. The astrophysical life extinction mechanisms which were proposed so far, in particular, meteoritic impacts, nearby supernova explosions, passage through molecular or dark matter clouds, and Galactic gamma/cosmic ray bursts cannot explain the time coincidences between these catastrophes. However, recent observations suggest that many planetary-mass objects may be present in the outer solar system between the Kuiper belt and the Oort cloud. Gravitational perturbations may occasionally bring them into the inner solar system. Their passage near Earth could have generated gigantic tidal waves, large volcanic eruptions, ...

3d object segmentation of point clouds using profiling techniques

African Journals Online (AJOL)

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optimization attempts to physically store the point cloud so that storage, retrieval and visualisation ..... Ideally three stacks should be sufficient, but in practice four or five are used. .... The authors would like to acknowledge that this paper is based on a paper presented at ... Theory, Processing and Application, 5 pages.

Spin-State-Dependent Ion-Molecule Chemistry as the Origin of N-15 and D Isotopic Anomalies in Primitive Matter.

Science.gov (United States)

Wirstrom, E. S.; Charnley, S. B.; Cordiner, M. A.; Milam, S. N.

2012-01-01

Many meteoritic and interplanetary dust particle (IDP) samples contain bulk enhancements and hotspots rich in N-15. Similarly low C(14)N/C(15)N ratios have been observed in numerous comets, An almost constant enrichment factor in comets from disti'nct formation zones in the nebular disk (i.e. both Jupiter Family and Oort Cloud comets), strongly suggests that this fractionation is primordial and was set in the protsolar cloud core. Deuterium enrichment is observed in both meteorites and IDPs

Sub-OBB based object recognition and localization algorithm using range images

International Nuclear Information System (INIS)

Hoang, Dinh-Cuong; Chen, Liang-Chia; Nguyen, Thanh-Hung

2017-01-01

This paper presents a novel approach to recognize and estimate pose of the 3D objects in cluttered range images. The key technical breakthrough of the developed approach can enable robust object recognition and localization under undesirable condition such as environmental illumination variation as well as optical occlusion to viewing the object partially. First, the acquired point clouds are segmented into individual object point clouds based on the developed 3D object segmentation for randomly stacked objects. Second, an efficient shape-matching algorithm called Sub-OBB based object recognition by using the proposed oriented bounding box (OBB) regional area-based descriptor is performed to reliably recognize the object. Then, the 3D position and orientation of the object can be roughly estimated by aligning the OBB of segmented object point cloud with OBB of matched point cloud in a database generated from CAD model and 3D virtual camera. To detect accurate pose of the object, the iterative closest point (ICP) algorithm is used to match the object model with the segmented point clouds. From the feasibility test of several scenarios, the developed approach is verified to be feasible for object pose recognition and localization. (paper)

Detection of water masers toward young stellar objects in the Large Magellanic Cloud

International Nuclear Information System (INIS)

Johanson, A. K.; Migenes, V.; Breen, S. L.

2014-01-01

We present results from a search for water maser emission toward N4A, N190, and N206, three regions of massive star formation in the Large Magellanic Cloud (LMC). Four water masers were detected; two toward N4A, and two toward N190. In the latter region, no previously known maser emission has been reported. Future studies of maser proper motion to determine the galactic dynamics of the LMC will benefit from the independent data points the new masers in N190 provide. Two of these masers are associated with previously identified massive young stellar objects (YSOs), which strongly supports the authenticity of the classification. We argue that the other two masers identify previously unknown YSOs. No masers were detected toward N206, but it does host a newly discovered 22 GHz continuum source, also associated with a massive YSO. We suggest that future surveys for water maser emission in the LMC be targeted toward the more luminous, massive YSOs.

THE CALIFORNIA MOLECULAR CLOUD

International Nuclear Information System (INIS)

Lada, Charles J.; Lombardi, Marco; Alves, Joao F.

2009-01-01

We present an analysis of wide-field infrared extinction maps of a region in Perseus just north of the Taurus-Auriga dark cloud complex. From this analysis we have identified a massive, nearby, but previously unrecognized, giant molecular cloud (GMC). Both a uniform foreground star density and measurements of the cloud's velocity field from CO observations indicate that this cloud is likely a coherent structure at a single distance. From comparison of foreground star counts with Galactic models, we derive a distance of 450 ± 23 pc to the cloud. At this distance the cloud extends over roughly 80 pc and has a mass of ∼ 10 5 M sun , rivaling the Orion (A) molecular cloud as the largest and most massive GMC in the solar neighborhood. Although surprisingly similar in mass and size to the more famous Orion molecular cloud (OMC) the newly recognized cloud displays significantly less star formation activity with more than an order of magnitude fewer young stellar objects than found in the OMC, suggesting that both the level of star formation and perhaps the star formation rate in this cloud are an order of magnitude or more lower than in the OMC. Analysis of extinction maps of both clouds shows that the new cloud contains only 10% the amount of high extinction (A K > 1.0 mag) material as is found in the OMC. This, in turn, suggests that the level of star formation activity and perhaps the star formation rate in these two clouds may be directly proportional to the total amount of high extinction material and presumably high density gas within them and that there might be a density threshold for star formation on the order of n(H 2 ) ∼ a few x 10 4 cm -3 .

Detectability of Sungrazing Comet Soft X-ray Irradiance

Directory of Open Access Journals (Sweden)

Su Yeon Oh

2007-12-01

Full Text Available Originating from the Oort cloud, some comets disappear to impact against the Sun or to split up by strong gravitational force. Then they don't go back to the Oort cloud. They are called sungrazing comets. The comets are detected by sublimation of ices and ejection of gas and dust through solar heat close to the Sun. There exists the charge transfer from heavy ions in the solar wind to neutral atoms in the cometary atmosphere by interaction with the solar wind. Cometary atoms would be excited to high electronic levels and their de-excitation would result in X-ray emission, or it would be scattering of solar X-ray emission by very small cometary grains. We calculated the X-ray emission applying the model suggested by Mendis & Flammer (1984 and Cravens (1997. In our estimation, the sungrazing comet whose nucleus size is about 1 km in radius might be detectable within a distance of 3 solar radius from the sun on soft X-ray solar camera.

Real time natural object modeling framework

International Nuclear Information System (INIS)

Rana, H.A.; Shamsuddin, S.M.; Sunar, M.H.

2008-01-01

CG (Computer Graphics) is a key technology for producing visual contents. Currently computer generated imagery techniques are being developed and applied, particularly in the field of virtual reality applications, film production, training and flight simulators, to provide total composition of realistic computer graphic images. Natural objects like clouds are an integral feature of the sky without them synthetic outdoor scenes seem unrealistic. Modeling and animating such objects is a difficult task. Most systems are difficult to use, as they require adjustment of numerous, complex parameters and are non-interactive. This paper presents an intuitive, interactive system to artistically model, animate, and render visually convincing clouds using modern graphics hardware. A high-level interface models clouds through the visual use of cubes. Clouds are rendered by making use of hardware accelerated API -OpenGL. The resulting interactive design and rendering system produces perceptually convincing cloud models that can be used in any interactive system. (author)

AMF3 CloudSat Overpasses Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Matrosov, Sergey [University of Colorado, Boulder; National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Hardin, Joseph [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); De Boer, Gijs [University of Colorado, Boulder; National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Shupe, Matthew [University of Colorado, Boulder; National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Maahn, Maximillian [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Williams, Christopher [University of Colorado, Boulder; National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.

2017-10-15

Synergy between ground-based and satellite radar observations of clouds and precipitation is important for refining the algorithms to retrieve hydrometeor microphysical parameters, improvements in the retrieval accuracy, and better understanding the advantages and limitations of different retrieval approaches. The new dual-frequency (Ka- and W-band, 35 GHz and 94 GHz) fully polarimetric scanning U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Research Facility cloud radars (SACRs-2) are advanced sensors aimed to significantly enhance remote sensing capabilities (Kollias et al. 2016). One of these radars was deployed as part of the third ARM Mobile Facility (AMF3) at Oliktok Point, Alaska (70.495o N, 149.886oW). The National Aeronautics and Space Administration (NASA) CloudSat satellite, which is part of the polar-orbiting A-train satellite constellation, passes over the vicinity of the AMF3 location (typically within 0-7 km depending on a particular overpass) on a descending orbit every 16 days at approximately 13:21 UTC. The nadir pointing W-band CloudSat cloud profiling radar (CPR) provides vertical profiles of reflectivity that are then used for retrievals of hydrometeor parameters (Tanelli et al. 2008). The main objective of the AMF3 CloudSat overpasses intensive operating period (IOP) campaign was to collect approximately collocated in space and time radar data from the SACR-2 and the CloudSat CPR measurements for subsequent joint analysis of radar variables and microphysical retrievals of cloud and precipitation parameters. Providing the reference for the SACR-2 absolute calibration from the well-calibrated CloudSat CPR was another objective of this IOP. The IOP objectives were achieved by conducting seven special SACR-2 scans during the 10.5-min period centered at the exact time of the CloudSat overpass over the AMF3 (~1321 UTC) on six dates of the CloudSat overpasses during the three-month period allocated to this IOP. These six days

The Clouds distributed operating system - Functional description, implementation details and related work

Science.gov (United States)

Dasgupta, Partha; Leblanc, Richard J., Jr.; Appelbe, William F.

1988-01-01

Clouds is an operating system in a novel class of distributed operating systems providing the integration, reliability, and structure that makes a distributed system usable. Clouds is designed to run on a set of general purpose computers that are connected via a medium-of-high speed local area network. The system structuring paradigm chosen for the Clouds operating system, after substantial research, is an object/thread model. All instances of services, programs and data in Clouds are encapsulated in objects. The concept of persistent objects does away with the need for file systems, and replaces it with a more powerful concept, namely the object system. The facilities in Clouds include integration of resources through location transparency; support for various types of atomic operations, including conventional transactions; advanced support for achieving fault tolerance; and provisions for dynamic reconfiguration.

Using Cloud-based Storage Technologies for Earth Science Data

Science.gov (United States)

Michaelis, A.; Readey, J.; Votava, P.

2016-12-01

Cloud based infrastructure may offer several key benefits of scalability, built in redundancy and reduced total cost of ownership as compared with a traditional data center approach. However, most of the tools and software systems developed for NASA data repositories were not developed with a cloud based infrastructure in mind and do not fully take advantage of commonly available cloud-based technologies. Object storage services are provided through all the leading public (Amazon Web Service, Microsoft Azure, Google Cloud, etc.) and private (Open Stack) clouds, and may provide a more cost-effective means of storing large data collections online. We describe a system that utilizes object storage rather than traditional file system based storage to vend earth science data. The system described is not only cost effective, but shows superior performance for running many different analytics tasks in the cloud. To enable compatibility with existing tools and applications, we outline client libraries that are API compatible with existing libraries for HDF5 and NetCDF4. Performance of the system is demonstrated using clouds services running on Amazon Web Services.

"Black cloud" vs. "white cloud" physicians - Myth or reality in apheresis medicine?

Science.gov (United States)

Pham, Huy P; Raju, Dheeraj; Jiang, Ning; Williams, Lance A

2017-08-01

Many practitioners believe in the phenomenon of either being labeled a "black cloud" or "white cloud" while on-call. A "white-cloud" physician is one who usually gets fewer cases. A "black-cloud" is one who often has more cases. It is unclear if the designation is only superstitious or if there is some merit. Our aim is to objectively assess this phenomenon in apheresis medicine at our center. A one-year prospective study from 12/2014 to 11/2015 was designed to evaluate the number of times apheresis physicians and nurses were involved with emergent apheresis procedures between the hours from 10 PM and 7 AM. Other parameters collected include the names of the physician, apheresis nurse, type of emergent apheresis procedure, day of the week, and season of the year. During the study period, 32 emergent procedures (or "black-cloud" events) occurred. The median time between two consecutive events was 8 days (range: 1-34 days). We found no statistically significant association between the "black-cloud" events and attending physicians, nurses, day of the week, or season of the year by Chi-square and Fisher's analyses. However, exploratory analysis using association rule demonstrated that "black-cloud" events were more likely to happen on Thursday (2.19 times), with attending physician 2 (1.18 times), and during winter (1.15 times). The results of this pilot study may support the common perception that some physicians or nurses are either "black cloud" or "white cloud". A larger, multi-center study population is needed to validate the results of this pilot study. © 2016 Wiley Periodicals, Inc.

Retrieval of Boundary Layer 3D Cloud Properties Using Scanning Cloud Radar and 3D Radiative Transfer

Energy Technology Data Exchange (ETDEWEB)

Marchand, Roger [Univ. of Washington, Seattle, WA (United States)

2017-01-24

Retrievals of cloud optical and microphysical properties for boundary layer clouds, including those widely used by ASR investigators, frequently assume that clouds are sufficiently horizontally homogeneous that scattering and absorption (at all wavelengths) can be treated using one dimensional (1D) radiative transfer, and that differences in the field-of-view of different sensors are unimportant. Unfortunately, most boundary layer clouds are far from horizontally homogeneous, and numerous theoretical and observational studies show that the assumption of horizontal homogeneity leads to significant errors. The introduction of scanning cloud and precipitation radars at the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program sites presents opportunities to move beyond the horizontally homogeneous assumption. The primary objective of this project was to develop a 3D retrieval for warm-phase (liquid only) boundary layer cloud microphysical properties, and to assess errors in current 1D (non-scanning) approaches. Specific research activities also involved examination of the diurnal cycle of hydrometeors as viewed by ARM cloud radar, and continued assessment of precipitation impacts on retrievals of cloud liquid water path using passive microwaves.

Fast Molecular Cloud Destruction Requires Fast Cloud Formation

Energy Technology Data Exchange (ETDEWEB)

Mac Low, Mordecai-Mark [American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024 (United States); Burkert, Andreas [Universitäts Sternwarte München, Ludwigs-Maximilian-Universität, D-81679 München (Germany); Ibáñez-Mejía, Juan C., E-mail: mordecai@amnh.org, E-mail: burkert@usm.lmu.de, E-mail: ibanez@ph1.uni-koeln.de [Max-Planck-Institut für Extraterrestrische Physik, D-85748 Garching bei München (Germany)

2017-09-20

A large fraction of the gas in the Galaxy is cold, dense, and molecular. If all this gas collapsed under the influence of gravity and formed stars in a local free-fall time, the star formation rate in the Galaxy would exceed that observed by more than an order of magnitude. Other star-forming galaxies behave similarly. Yet, observations and simulations both suggest that the molecular gas is indeed gravitationally collapsing, albeit hierarchically. Prompt stellar feedback offers a potential solution to the low observed star formation rate if it quickly disrupts star-forming clouds during gravitational collapse. However, this requires that molecular clouds must be short-lived objects, raising the question of how so much gas can be observed in the molecular phase. This can occur only if molecular clouds form as quickly as they are destroyed, maintaining a global equilibrium fraction of dense gas. We therefore examine cloud formation timescales. We first demonstrate that supernova and superbubble sweeping cannot produce dense gas at the rate required to match the cloud destruction rate. On the other hand, Toomre gravitational instability can reach the required production rate. We thus argue that, although dense, star-forming gas may last only around a single global free-fall time; the dense gas in star-forming galaxies can globally exist in a state of dynamic equilibrium between formation by gravitational instability and disruption by stellar feedback. At redshift z ≳ 2, the Toomre instability timescale decreases, resulting in a prediction of higher molecular gas fractions at early times, in agreement with the observations.

Sharing Elderly Healthcare information on Cloud Computing

OpenAIRE

Lu, Fangjie; Khan, Israr

2012-01-01

Context: Due to rapid increase in the population of elderly people, sharing healthcare information has become an essential requirement for the development of e-health system. By conducting a research in e-health and cloud computing we have explored the advantages and disadvantages of sharing healthcare information for elderly people through cloud computing. Objectives: The main purpose of this research is to investigate the suitability of cloud computing to share healthcare information. The s...

Exploring the factors influencing the cloud computing adoption: a systematic study on cloud migration.

Science.gov (United States)

Rai, Rashmi; Sahoo, Gadadhar; Mehfuz, Shabana

2015-01-01

Today, most of the organizations trust on their age old legacy applications, to support their business-critical systems. However, there are several critical concerns, as maintainability and scalability issues, associated with the legacy system. In this background, cloud services offer a more agile and cost effective platform, to support business applications and IT infrastructure. As the adoption of cloud services has been increasing recently and so has been the academic research in cloud migration. However, there is a genuine need of secondary study to further strengthen this research. The primary objective of this paper is to scientifically and systematically identify, categorize and compare the existing research work in the area of legacy to cloud migration. The paper has also endeavored to consolidate the research on Security issues, which is prime factor hindering the adoption of cloud through classifying the studies on secure cloud migration. SLR (Systematic Literature Review) of thirty selected papers, published from 2009 to 2014 was conducted to properly understand the nuances of the security framework. To categorize the selected studies, authors have proposed a conceptual model for cloud migration which has resulted in a resource base of existing solutions for cloud migration. This study concludes that cloud migration research is in seminal stage but simultaneously it is also evolving and maturing, with increasing participation from academics and industry alike. The paper also identifies the need for a secure migration model, which can fortify organization's trust into cloud migration and facilitate necessary tool support to automate the migration process.

Marine Cloud Brightening

Energy Technology Data Exchange (ETDEWEB)

Latham, John; Bower, Keith; Choularton, Tom; Coe, H.; Connolly, P.; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Philip J.; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Robert

2012-09-07

The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could - subject to satisfactory resolution of technical and scientific problems identified herein - have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seedparticle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

Marine cloud brightening.

Science.gov (United States)

Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Phillip; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Rob

2012-09-13

The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could-subject to satisfactory resolution of technical and scientific problems identified herein-have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

Cloud Infrastructure & Applications - CloudIA

Science.gov (United States)

Sulistio, Anthony; Reich, Christoph; Doelitzscher, Frank

The idea behind Cloud Computing is to deliver Infrastructure-as-a-Services and Software-as-a-Service over the Internet on an easy pay-per-use business model. To harness the potentials of Cloud Computing for e-Learning and research purposes, and to small- and medium-sized enterprises, the Hochschule Furtwangen University establishes a new project, called Cloud Infrastructure & Applications (CloudIA). The CloudIA project is a market-oriented cloud infrastructure that leverages different virtualization technologies, by supporting Service-Level Agreements for various service offerings. This paper describes the CloudIA project in details and mentions our early experiences in building a private cloud using an existing infrastructure.

Primordial Molecular Cloud Material in Metal-Rich Carbonaceous Chondrites

Science.gov (United States)

Taylor, G. J.

2016-03-01

The menagerie of objects that make up our Solar System reflects the composition of the huge molecular cloud in which the Sun formed, a late addition of short-lived isotopes from an exploding supernova or stellar winds from a neighboring massive star, heating and/or alteration by water in growing planetesimals that modified and segregated the primordial components, and mixing throughout the Solar System. Outer Solar System objects, such as comets, have always been cold, hence minimizing the changes experienced by more processed objects. They are thought to preserve information about the molecular cloud. Elishevah Van Kooten (Natural History Museum of Denmark and the University of Copenhagen) and co-authors in Denmark and at the University of Hawai'i, measured the isotopic compositions of magnesium and chromium in metal-rich carbonaceous chondrites. They found that the meteorites preserve an isotopic signature of primordial molecular cloud materials, providing a potentially detailed record of the molecular cloud's composition and of materials that formed in the outer Solar System.

SEMANTIC SEGMENTATION OF BUILDING ELEMENTS USING POINT CLOUD HASHING

Directory of Open Access Journals (Sweden)

M. Chizhova

2018-05-01

Full Text Available For the interpretation of point clouds, the semantic definition of extracted segments from point clouds or images is a common problem. Usually, the semantic of geometrical pre-segmented point cloud elements are determined using probabilistic networks and scene databases. The proposed semantic segmentation method is based on the psychological human interpretation of geometric objects, especially on fundamental rules of primary comprehension. Starting from these rules the buildings could be quite well and simply classified by a human operator (e.g. architect into different building types and structural elements (dome, nave, transept etc., including particular building parts which are visually detected. The key part of the procedure is a novel method based on hashing where point cloud projections are transformed into binary pixel representations. A segmentation approach released on the example of classical Orthodox churches is suitable for other buildings and objects characterized through a particular typology in its construction (e.g. industrial objects in standardized enviroments with strict component design allowing clear semantic modelling.

Cloud Detection by Fusing Multi-Scale Convolutional Features

Science.gov (United States)

Li, Zhiwei; Shen, Huanfeng; Wei, Yancong; Cheng, Qing; Yuan, Qiangqiang

2018-04-01

Clouds detection is an important pre-processing step for accurate application of optical satellite imagery. Recent studies indicate that deep learning achieves best performance in image segmentation tasks. Aiming at boosting the accuracy of cloud detection for multispectral imagery, especially for those that contain only visible and near infrared bands, in this paper, we proposed a deep learning based cloud detection method termed MSCN (multi-scale cloud net), which segments cloud by fusing multi-scale convolutional features. MSCN was trained on a global cloud cover validation collection, and was tested in more than ten types of optical images with different resolution. Experiment results show that MSCN has obvious advantages over the traditional multi-feature combined cloud detection method in accuracy, especially when in snow and other areas covered by bright non-cloud objects. Besides, MSCN produced more detailed cloud masks than the compared deep cloud detection convolution network. The effectiveness of MSCN make it promising for practical application in multiple kinds of optical imagery.

Application of cloud services in education

Directory of Open Access Journals (Sweden)

G. Kiryakova

2017-09-01

Full Text Available Educational institutions in information society rely heavily on information and communication technologies. They allow them to follow innovative pedagogical paradigms and approaches and implement modern forms of training that are tailored to the needs and characteristics of the new generation of learners. More and more educational institutions are turning to the use of cloud services, because they are extremely effective alternative for providing the high quality resources and services to all participants in the learning process at an affordable price. The main objective of this study is to present the most popular cloud services – cloud-based office suites and cloud storage services, focusing on their use in education.

The Role of Standards in Cloud-Computing Interoperability

Science.gov (United States)

2012-10-01

services are not shared outside the organization. CloudStack, Eucalyptus, HP, Microsoft, OpenStack , Ubuntu, and VMWare provide tools for building...center requirements • Developing usage models for cloud ven- dors • Independent IT consortium OpenStack http://www.openstack.org • Open-source...software for running private clouds • Currently consists of three core software projects: OpenStack Compute (Nova), OpenStack Object Storage (Swift

Treatment of cloud radiative effects in general circulation models

Energy Technology Data Exchange (ETDEWEB)

Wang, W.C.; Dudek, M.P.; Liang, X.Z.; Ding, M. [State Univ. of New York, Albany, NY (United States)] [and others

1996-04-01

We participate in the Atmospheric Radiation Measurement (ARM) program with two objectives: (1) to improve the general circulation model (GCM) cloud/radiation treatment with a focus on cloud verticle overlapping and layer cloud optical properties, and (2) to study the effects of cloud/radiation-climate interaction on GCM climate simulations. This report summarizes the project progress since the Fourth ARM Science Team meeting February 28-March 4, 1994, in Charleston, South Carolina.

Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision

OpenAIRE

Inoue, Tsuyoshi; Fukui, Yasuo

2013-01-01

Recent observations of molecular clouds around rich massive star clusters including NGC3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by the cloud-cloud collision. We find that the massive mol...

NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. II. MOLECULAR CLOUD ENVIRONMENTS

Energy Technology Data Exchange (ETDEWEB)

Chen Xi; Gan Conggui; Shen Zhiqiang [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Ellingsen, Simon P.; Titmarsh, Anita [School of Mathematics and Physics, University of Tasmania, Hobart, Tasmania (Australia); He Jinhua, E-mail: chenxi@shao.ac.cn [Key Laboratory for the Structure and Evolution of Celestial Objects, Yunnan Astronomical Observatory/National Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011, Yunnan Province (China)

2013-06-01

We have undertaken a survey of molecular lines in the 3 mm band toward 57 young stellar objects using the Australia Telescope National Facility Mopra 22 m radio telescope. The target sources were young stellar objects with active outflows (extended green objects (EGOs)) newly identified from the GLIMPSE II survey. We observe a high detection rate (50%) of broad line wing emission in the HNC and CS thermal lines, which combined with the high detection rate of class I methanol masers toward these sources (reported in Paper I) further demonstrates that the GLIMPSE II EGOs are associated with outflows. The physical and kinematic characteristics derived from the 3 mm molecular lines for these newly identified EGOs are consistent with these sources being massive young stellar objects with ongoing outflow activity and rapid accretion. These findings support our previous investigations of the mid-infrared properties of these sources and their association with other star formation tracers (e.g., infrared dark clouds, methanol masers and millimeter dust sources) presented in Paper I. The high detection rate (64%) of the hot core tracer CH{sub 3}CN reveals that the majority of these new EGOs have evolved to the hot molecular core stage. Comparison of the observed molecular column densities with predictions from hot core chemistry models reveals that the newly identified EGOs from the GLIMPSE II survey are members of the youngest hot core population, with an evolutionary time scale of the order of 10{sup 3} yr.

Cloud essentials CompTIA authorized courseware for exam CLO-001

CERN Document Server

Hausman, Kirk; Sampaio, Telmo

2013-01-01

CompTIA-Authorized courseware for the Cloud Essentials Exam (CLO-001) What better way to get up to speed on cloud computing than with this new book in the popular Sybex Essentials series? Cloud Essentials covers the basics of cloud computing and its place in the modern enterprise. Explore public and private clouds; contrast the ""as a service"" models for PaaS, SaaS, IaaS, or XaaS platforms; plan security; and more. In addition, the book covers the exam objectives for the both the CompTIA Cloud Essentials (Exam CLO-001) exam and the EXIN Cloud Computing Foundation (EX0-1

Cloud Computing for Geosciences--GeoCloud for standardized geospatial service platforms (Invited)

Science.gov (United States)

Nebert, D. D.; Huang, Q.; Yang, C.

2013-12-01

The 21st century geoscience faces challenges of Big Data, spike computing requirements (e.g., when natural disaster happens), and sharing resources through cyberinfrastructure across different organizations (Yang et al., 2011). With flexibility and cost-efficiency of computing resources a primary concern, cloud computing emerges as a promising solution to provide core capabilities to address these challenges. Many governmental and federal agencies are adopting cloud technologies to cut costs and to make federal IT operations more efficient (Huang et al., 2010). However, it is still difficult for geoscientists to take advantage of the benefits of cloud computing to facilitate the scientific research and discoveries. This presentation reports using GeoCloud to illustrate the process and strategies used in building a common platform for geoscience communities to enable the sharing, integration of geospatial data, information and knowledge across different domains. GeoCloud is an annual incubator project coordinated by the Federal Geographic Data Committee (FGDC) in collaboration with the U.S. General Services Administration (GSA) and the Department of Health and Human Services. It is designed as a staging environment to test and document the deployment of a common GeoCloud community platform that can be implemented by multiple agencies. With these standardized virtual geospatial servers, a variety of government geospatial applications can be quickly migrated to the cloud. In order to achieve this objective, multiple projects are nominated each year by federal agencies as existing public-facing geospatial data services. From the initial candidate projects, a set of common operating system and software requirements was identified as the baseline for platform as a service (PaaS) packages. Based on these developed common platform packages, each project deploys and monitors its web application, develops best practices, and documents cost and performance information. This

Point Cloud Management Through the Realization of the Intelligent Cloud Viewer Software

Science.gov (United States)

Costantino, D.; Angelini, M. G.; Settembrini, F.

2017-05-01

The paper presents a software dedicated to the elaboration of point clouds, called Intelligent Cloud Viewer (ICV), made in-house by AESEI software (Spin-Off of Politecnico di Bari), allowing to view point cloud of several tens of millions of points, also on of "no" very high performance systems. The elaborations are carried out on the whole point cloud and managed by means of the display only part of it in order to speed up rendering. It is designed for 64-bit Windows and is fully written in C ++ and integrates different specialized modules for computer graphics (Open Inventor by SGI, Silicon Graphics Inc), maths (BLAS, EIGEN), computational geometry (CGAL, Computational Geometry Algorithms Library), registration and advanced algorithms for point clouds (PCL, Point Cloud Library), advanced data structures (BOOST, Basic Object Oriented Supporting Tools), etc. ICV incorporates a number of features such as, for example, cropping, transformation and georeferencing, matching, registration, decimation, sections, distances calculation between clouds, etc. It has been tested on photographic and TLS (Terrestrial Laser Scanner) data, obtaining satisfactory results. The potentialities of the software have been tested by carrying out the photogrammetric survey of the Castel del Monte which was already available in previous laser scanner survey made from the ground by the same authors. For the aerophotogrammetric survey has been adopted a flight height of approximately 1000ft AGL (Above Ground Level) and, overall, have been acquired over 800 photos in just over 15 minutes, with a covering not less than 80%, the planned speed of about 90 knots.

POINT CLOUD MANAGEMENT THROUGH THE REALIZATION OF THE INTELLIGENT CLOUD VIEWER SOFTWARE

Directory of Open Access Journals (Sweden)

D. Costantino

2017-05-01

Full Text Available The paper presents a software dedicated to the elaboration of point clouds, called Intelligent Cloud Viewer (ICV, made in-house by AESEI software (Spin-Off of Politecnico di Bari, allowing to view point cloud of several tens of millions of points, also on of “no” very high performance systems. The elaborations are carried out on the whole point cloud and managed by means of the display only part of it in order to speed up rendering. It is designed for 64-bit Windows and is fully written in C ++ and integrates different specialized modules for computer graphics (Open Inventor by SGI, Silicon Graphics Inc, maths (BLAS, EIGEN, computational geometry (CGAL, Computational Geometry Algorithms Library, registration and advanced algorithms for point clouds (PCL, Point Cloud Library, advanced data structures (BOOST, Basic Object Oriented Supporting Tools, etc. ICV incorporates a number of features such as, for example, cropping, transformation and georeferencing, matching, registration, decimation, sections, distances calculation between clouds, etc. It has been tested on photographic and TLS (Terrestrial Laser Scanner data, obtaining satisfactory results. The potentialities of the software have been tested by carrying out the photogrammetric survey of the Castel del Monte which was already available in previous laser scanner survey made from the ground by the same authors. For the aerophotogrammetric survey has been adopted a flight height of approximately 1000ft AGL (Above Ground Level and, overall, have been acquired over 800 photos in just over 15 minutes, with a covering not less than 80%, the planned speed of about 90 knots.

Relationship between cloud radiative forcing, cloud fraction and cloud albedo, and new surface-based approach for determining cloud albedo

OpenAIRE

Y. Liu; W. Wu; M. P. Jensen; T. Toto

2011-01-01

This paper focuses on three interconnected topics: (1) quantitative relationship between surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo; (2) surfaced-based approach for measuring cloud albedo; (3) multiscale (diurnal, annual and inter-annual) variations and covariations of surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo. An analytical expression is first derived to quantify the relationship between cloud radiative forcing, cloud fractio...

SUPERGIANT SHELLS AND MOLECULAR CLOUD FORMATION IN THE LARGE MAGELLANIC CLOUD

Energy Technology Data Exchange (ETDEWEB)

Dawson, J. R.; Dickey, John M. [School of Mathematics and Physics, University of Tasmania, Sandy Bay Campus, Churchill Avenue, Sandy Bay, TAS 7005 (Australia); McClure-Griffiths, N. M. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Marsfield NSW 2122 (Australia); Wong, T. [Astronomy Department, University of Illinois, Urbana, IL 61801 (United States); Hughes, A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany); Fukui, Y. [Department of Physics and Astrophysics, Nagoya University, Chikusa-ku, Nagoya (Japan); Kawamura, A., E-mail: joanne.dawson@utas.edu.au [National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan)

2013-01-20

We investigate the influence of large-scale stellar feedback on the formation of molecular clouds in the Large Magellanic Cloud (LMC). Examining the relationship between H I and {sup 12}CO(J = 1-0) in supergiant shells (SGSs), we find that the molecular fraction in the total volume occupied by SGSs is not enhanced with respect to the rest of the LMC disk. However, the majority of objects ({approx}70% by mass) are more molecular than their local surroundings, implying that the presence of a supergiant shell does on average have a positive effect on the molecular gas fraction. Averaged over the full SGS sample, our results suggest that {approx}12%-25% of the molecular mass in supergiant shell systems was formed as a direct result of the stellar feedback that created the shells. This corresponds to {approx}4%-11% of the total molecular mass of the galaxy. These figures are an approximate lower limit to the total contribution of stellar feedback to molecular cloud formation in the LMC, and constitute one of the first quantitative measurements of feedback-triggered molecular cloud formation in a galactic system.

Data provenance assurance in the cloud using blockchain

Science.gov (United States)

Shetty, Sachin; Red, Val; Kamhoua, Charles; Kwiat, Kevin; Njilla, Laurent

2017-05-01

Ever increasing adoption of cloud technology scales up the activities like creation, exchange, and alteration of cloud data objects, which create challenges to track malicious activities and security violations. Addressing this issue requires implementation of data provenance framework so that each data object in the federated cloud environment can be tracked and recorded but cannot be modified. The blockchain technology gives a promising decentralized platform to build tamper-proof systems. Its incorruptible distributed ledger/blockchain complements the need of maintaining cloud data provenance. In this paper, we present a cloud based data provenance framework using block chain which traces data record operations and generates provenance data. We anchor provenance data records into block chain transactions, which provide validation on provenance data and preserve user privacy at the same time. Once the provenance data is uploaded to the global block chain network, it is extremely challenging to tamper the provenance data. Besides, the provenance data uses hashed user identifiers prior to uploading so the blockchain nodes cannot link the operations to a particular user. The framework ensures that the privacy is preserved. We implemented the architecture on ownCloud, uploaded records to blockchain network, stored records in a provenance database and developed a prototype in form of a web service.

Marine cloud brightening

Science.gov (United States)

Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Phillip; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Rob

2012-01-01

The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could—subject to satisfactory resolution of technical and scientific problems identified herein—have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud–albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action

THE MAGELLANIC MOPRA ASSESSMENT (MAGMA). I. THE MOLECULAR CLOUD POPULATION OF THE LARGE MAGELLANIC CLOUD

International Nuclear Information System (INIS)

Wong, Tony; Chu, You-Hua; Gruendl, Robert A.; Looney, Leslie W.; Seale, Jonathan; Welty, Daniel E.; Hughes, Annie; Maddison, Sarah; Ott, Jürgen; Muller, Erik; Fukui, Yasuo; Kawamura, Akiko; Mizuno, Yoji; Pineda, Jorge L.; Bernard, Jean-Philippe; Paradis, Deborah; Henkel, Christian; Klein, Ulrich

2011-01-01

We present the properties of an extensive sample of molecular clouds in the Large Magellanic Cloud (LMC) mapped at 11 pc resolution in the CO(1-0) line. Targets were chosen based on a limiting CO flux and peak brightness as measured by the NANTEN survey. The observations were conducted with the ATNF Mopra Telescope as part of the Magellanic Mopra Assessment. We identify clouds as regions of connected CO emission and find that the distributions of cloud sizes, fluxes, and masses are sensitive to the choice of decomposition parameters. In all cases, however, the luminosity function of CO clouds is steeper than dN/dL∝L –2 , suggesting that a substantial fraction of mass is in low-mass clouds. A correlation between size and linewidth, while apparent for the largest emission structures, breaks down when those structures are decomposed into smaller structures. We argue that the correlation between virial mass and CO luminosity is the result of comparing two covariant quantities, with the correlation appearing tighter on larger scales where a size-linewidth relation holds. The virial parameter (the ratio of a cloud's kinetic to self-gravitational energy) shows a wide range of values and exhibits no clear trends with the CO luminosity or the likelihood of hosting young stellar object (YSO) candidates, casting further doubt on the assumption of virialization for molecular clouds in the LMC. Higher CO luminosity increases the likelihood of a cloud harboring a YSO candidate, and more luminous YSOs are more likely to be coincident with detectable CO emission, confirming the close link between giant molecular clouds and massive star formation.

OGLE Collection of Star Clusters. New Objects in the Outskirts of the Large Magellanic Cloud

OpenAIRE

Sitek, M.; Szymański, M. K.; Skowron, D. M.; Udalski, A.; Kostrzewa-Rutkowska, Z.; Skowron, J.; Karczmarek, P.; Cieślar, M.; Wyrzykowski, Ł.; Kozłowski, S.; Pietrukowicz, P.; Soszyński, I.; Mróz, P.; Pawlak, M.; Poleski, R.

2016-01-01

The Magellanic System (MS), consisting of the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) and the Magellanic Bridge (MBR), contains diverse sample of star clusters. Their spatial distribution, ages and chemical abundances may provide important information about the history of formation of the whole System. We use deep photometric maps derived from the images collected during the fourth phase of The Optical Gravitational Lensing Experiment (OGLE-IV) to construct the most com...

Meteors, meteorites and cosmic dust

International Nuclear Information System (INIS)

Lebedinets, V.N.

1987-01-01

The problem of meteorite origin and meteorite composition is discussed. Nowadays, most scientists suppose that the giant Oort cloud consisting of ice comet nuclei is the sourse of the meteor matter. A principle unity of the matter of meteorites falling to the Earth and cosmic dust is noted as well as that of meteorite bodies evaporating in the atmosphere and bearing meteors and bodies

IMAGE TO POINT CLOUD METHOD OF 3D-MODELING

Directory of Open Access Journals (Sweden)

A. G. Chibunichev

2012-07-01

Full Text Available This article describes the method of constructing 3D models of objects (buildings, monuments based on digital images and a point cloud obtained by terrestrial laser scanner. The first step is the automated determination of exterior orientation parameters of digital image. We have to find the corresponding points of the image and point cloud to provide this operation. Before the corresponding points searching quasi image of point cloud is generated. After that SIFT algorithm is applied to quasi image and real image. SIFT algorithm allows to find corresponding points. Exterior orientation parameters of image are calculated from corresponding points. The second step is construction of the vector object model. Vectorization is performed by operator of PC in an interactive mode using single image. Spatial coordinates of the model are calculated automatically by cloud points. In addition, there is automatic edge detection with interactive editing available. Edge detection is performed on point cloud and on image with subsequent identification of correct edges. Experimental studies of the method have demonstrated its efficiency in case of building facade modeling.

Scanning Cloud Radar Observations at Azores: Preliminary 3D Cloud Products

Energy Technology Data Exchange (ETDEWEB)

Kollias, P.; Johnson, K.; Jo, I.; Tatarevic, A.; Giangrande, S.; Widener, K.; Bharadwaj, N.; Mead, J.

2010-03-15

The deployment of the Scanning W-Band ARM Cloud Radar (SWACR) during the AMF campaign at Azores signals the first deployment of an ARM Facility-owned scanning cloud radar and offers a prelude for the type of 3D cloud observations that ARM will have the capability to provide at all the ARM Climate Research Facility sites by the end of 2010. The primary objective of the deployment of Scanning ARM Cloud Radars (SACRs) at the ARM Facility sites is to map continuously (operationally) the 3D structure of clouds and shallow precipitation and to provide 3D microphysical and dynamical retrievals for cloud life cycle and cloud-scale process studies. This is a challenging task, never attempted before, and requires significant research and development efforts in order to understand the radar's capabilities and limitations. At the same time, we need to look beyond the radar meteorology aspects of the challenge and ensure that the hardware and software capabilities of the new systems are utilized for the development of 3D data products that address the scientific needs of the new Atmospheric System Research (ASR) program. The SWACR observations at Azores provide a first look at such observations and the challenges associated with their analysis and interpretation. The set of scan strategies applied during the SWACR deployment and their merit is discussed. The scan strategies were adjusted for the detection of marine stratocumulus and shallow cumulus that were frequently observed at the Azores deployment. Quality control procedures for the radar reflectivity and Doppler products are presented. Finally, preliminary 3D-Active Remote Sensing of Cloud Locations (3D-ARSCL) products on a regular grid will be presented, and the challenges associated with their development discussed. In addition to data from the Azores deployment, limited data from the follow-up deployment of the SWACR at the ARM SGP site will be presented. This effort provides a blueprint for the effort required

Cloud-Top Entrainment in Stratocumulus Clouds

Science.gov (United States)

Mellado, Juan Pedro

2017-01-01

Cloud entrainment, the mixing between cloudy and clear air at the boundary of clouds, constitutes one paradigm for the relevance of small scales in the Earth system: By regulating cloud lifetimes, meter- and submeter-scale processes at cloud boundaries can influence planetary-scale properties. Understanding cloud entrainment is difficult given the complexity and diversity of the associated phenomena, which include turbulence entrainment within a stratified medium, convective instabilities driven by radiative and evaporative cooling, shear instabilities, and cloud microphysics. Obtaining accurate data at the required small scales is also challenging, for both simulations and measurements. During the past few decades, however, high-resolution simulations and measurements have greatly advanced our understanding of the main mechanisms controlling cloud entrainment. This article reviews some of these advances, focusing on stratocumulus clouds, and indicates remaining challenges.

Cloud type comparisons of AIRS, CloudSat, and CALIPSO cloud height and amount

Directory of Open Access Journals (Sweden)

B. H. Kahn

2008-03-01

Full Text Available The precision of the two-layer cloud height fields derived from the Atmospheric Infrared Sounder (AIRS is explored and quantified for a five-day set of observations. Coincident profiles of vertical cloud structure by CloudSat, a 94 GHz profiling radar, and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO, are compared to AIRS for a wide range of cloud types. Bias and variability in cloud height differences are shown to have dependence on cloud type, height, and amount, as well as whether CloudSat or CALIPSO is used as the comparison standard. The CloudSat-AIRS biases and variability range from −4.3 to 0.5±1.2–3.6 km for all cloud types. Likewise, the CALIPSO-AIRS biases range from 0.6–3.0±1.2–3.6 km (−5.8 to −0.2±0.5–2.7 km for clouds ≥7 km (<7 km. The upper layer of AIRS has the greatest sensitivity to Altocumulus, Altostratus, Cirrus, Cumulonimbus, and Nimbostratus, whereas the lower layer has the greatest sensitivity to Cumulus and Stratocumulus. Although the bias and variability generally decrease with increasing cloud amount, the ability of AIRS to constrain cloud occurrence, height, and amount is demonstrated across all cloud types for many geophysical conditions. In particular, skill is demonstrated for thin Cirrus, as well as some Cumulus and Stratocumulus, cloud types infrared sounders typically struggle to quantify. Furthermore, some improvements in the AIRS Version 5 operational retrieval algorithm are demonstrated. However, limitations in AIRS cloud retrievals are also revealed, including the existence of spurious Cirrus near the tropopause and low cloud layers within Cumulonimbus and Nimbostratus clouds. Likely causes of spurious clouds are identified and the potential for further improvement is discussed.

A comparison of shock-cloud and wind-cloud interactions: effect of increased cloud density contrast on cloud evolution

Science.gov (United States)

Goldsmith, K. J. A.; Pittard, J. M.

2018-05-01

The similarities, or otherwise, of a shock or wind interacting with a cloud of density contrast χ = 10 were explored in a previous paper. Here, we investigate such interactions with clouds of higher density contrast. We compare the adiabatic hydrodynamic interaction of a Mach 10 shock with a spherical cloud of χ = 103 with that of a cloud embedded in a wind with identical parameters to the post-shock flow. We find that initially there are only minor morphological differences between the shock-cloud and wind-cloud interactions, compared to when χ = 10. However, once the transmitted shock exits the cloud, the development of a turbulent wake and fragmentation of the cloud differs between the two simulations. On increasing the wind Mach number, we note the development of a thin, smooth tail of cloud material, which is then disrupted by the fragmentation of the cloud core and subsequent `mass-loading' of the flow. We find that the normalized cloud mixing time (tmix) is shorter at higher χ. However, a strong Mach number dependence on tmix and the normalized cloud drag time, t_{drag}^' }, is not observed. Mach-number-dependent values of tmix and t_{drag}^' } from comparable shock-cloud interactions converge towards the Mach-number-independent time-scales of the wind-cloud simulations. We find that high χ clouds can be accelerated up to 80-90 per cent of the wind velocity and travel large distances before being significantly mixed. However, complete mixing is not achieved in our simulations and at late times the flow remains perturbed.

OGLE Collection of Star Clusters. New Objects in the Outskirts of the Large Magellanic Cloud

Science.gov (United States)

Sitek, M.; Szymański, M. K.; Skowron, D. M.; Udalski, A.; Kostrzewa-Rutkowska, Z.; Skowron, J.; Karczmarek, P.; Cieślar, M.; Wyrzykowski, Ł.; Kozłowski, S.; Pietrukowicz, P.; Soszyński, I.; Mróz, P.; Pawlak, M.; Poleski, R.; Ulaczyk, K.

2016-09-01

The Magellanic System (MS), consisting of the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) and the Magellanic Bridge (MBR), contains diverse sample of star clusters. Their spatial distribution, ages and chemical abundances may provide important information about the history of formation of the whole System. We use deep photometric maps derived from the images collected during the fourth phase of the Optical Gravitational Lensing Experiment (OGLE-IV) to construct the most complete catalog of star clusters in the Large Magellanic Cloud using the homogeneous photometric data. In this paper we present the collection of star clusters found in the area of about 225 square degrees in the outer regions of the LMC. Our sample contains 679 visually identified star cluster candidates, 226 of which were not listed in any of the previously published catalogs. The new clusters are mainly young small open clusters or clusters similar to associations.

Cloud Computing, Tieto Cloud Server Model

OpenAIRE

Suikkanen, Saara

2013-01-01

The purpose of this study is to find out what is cloud computing. To be able to make wise decisions when moving to cloud or considering it, companies need to understand what cloud is consists of. Which model suits best to they company, what should be taken into account before moving to cloud, what is the cloud broker role and also SWOT analysis of cloud? To be able to answer customer requirements and business demands, IT companies should develop and produce new service models. IT house T...

Design and Implementation of a Cloud Computing Adoption Decision Tool: Generating a Cloud Road

Science.gov (United States)

Bildosola, Iñaki; Río-Belver, Rosa; Cilleruelo, Ernesto; Garechana, Gaizka

2015-01-01

Migrating to cloud computing is one of the current enterprise challenges. This technology provides a new paradigm based on “on-demand payment” for information and communication technologies. In this sense, the small and medium enterprise is supposed to be the most interested, since initial investments are avoided and the technology allows gradual implementation. However, even if the characteristics and capacities have been widely discussed, entry into the cloud is still lacking in terms of practical, real frameworks. This paper aims at filling this gap, presenting a real tool already implemented and tested, which can be used as a cloud computing adoption decision tool. This tool uses diagnosis based on specific questions to gather the required information and subsequently provide the user with valuable information to deploy the business within the cloud, specifically in the form of Software as a Service (SaaS) solutions. This information allows the decision makers to generate their particular Cloud Road. A pilot study has been carried out with enterprises at a local level with a two-fold objective: to ascertain the degree of knowledge on cloud computing and to identify the most interesting business areas and their related tools for this technology. As expected, the results show high interest and low knowledge on this subject and the tool presented aims to readdress this mismatch, insofar as possible. PMID:26230400

Design and Implementation of a Cloud Computing Adoption Decision Tool: Generating a Cloud Road.

Directory of Open Access Journals (Sweden)

Iñaki Bildosola

Full Text Available Migrating to cloud computing is one of the current enterprise challenges. This technology provides a new paradigm based on "on-demand payment" for information and communication technologies. In this sense, the small and medium enterprise is supposed to be the most interested, since initial investments are avoided and the technology allows gradual implementation. However, even if the characteristics and capacities have been widely discussed, entry into the cloud is still lacking in terms of practical, real frameworks. This paper aims at filling this gap, presenting a real tool already implemented and tested, which can be used as a cloud computing adoption decision tool. This tool uses diagnosis based on specific questions to gather the required information and subsequently provide the user with valuable information to deploy the business within the cloud, specifically in the form of Software as a Service (SaaS solutions. This information allows the decision makers to generate their particular Cloud Road. A pilot study has been carried out with enterprises at a local level with a two-fold objective: to ascertain the degree of knowledge on cloud computing and to identify the most interesting business areas and their related tools for this technology. As expected, the results show high interest and low knowledge on this subject and the tool presented aims to readdress this mismatch, insofar as possible.

Design and Implementation of a Cloud Computing Adoption Decision Tool: Generating a Cloud Road.

Science.gov (United States)

Bildosola, Iñaki; Río-Belver, Rosa; Cilleruelo, Ernesto; Garechana, Gaizka

2015-01-01

Migrating to cloud computing is one of the current enterprise challenges. This technology provides a new paradigm based on "on-demand payment" for information and communication technologies. In this sense, the small and medium enterprise is supposed to be the most interested, since initial investments are avoided and the technology allows gradual implementation. However, even if the characteristics and capacities have been widely discussed, entry into the cloud is still lacking in terms of practical, real frameworks. This paper aims at filling this gap, presenting a real tool already implemented and tested, which can be used as a cloud computing adoption decision tool. This tool uses diagnosis based on specific questions to gather the required information and subsequently provide the user with valuable information to deploy the business within the cloud, specifically in the form of Software as a Service (SaaS) solutions. This information allows the decision makers to generate their particular Cloud Road. A pilot study has been carried out with enterprises at a local level with a two-fold objective: to ascertain the degree of knowledge on cloud computing and to identify the most interesting business areas and their related tools for this technology. As expected, the results show high interest and low knowledge on this subject and the tool presented aims to readdress this mismatch, insofar as possible.

Sharing Planetary-Scale Data in the Cloud

Science.gov (United States)

Sundwall, J.; Flasher, J.

2016-12-01

On 19 March 2015, Amazon Web Services (AWS) announced Landsat on AWS, an initiative to make data from the U.S. Geological Survey's Landsat satellite program freely available in the cloud. Because of Landsat's global coverage and long history, it has become a reference point for all Earth observation work and is considered the gold standard of natural resource satellite imagery. Within the first year of Landsat on AWS, the service served over a billion requests for Landsat imagery and metadata, globally. Availability of the data in the cloud has led to new product development by companies and startups including Mapbox, Esri, CartoDB, MathWorks, Development Seed, Trimble, Astro Digital, Blue Raster and Timbr.io. The model of staging data for analysis in the cloud established by Landsat on AWS has since been applied to high resolution radar data, European Space Agency satellite imagery, global elevation data and EPA air quality models. This session will provide an overview of lessons learned throughout these projects. It will demonstrate how cloud-based object storage is democratizing access to massive publicly-funded data sets that have previously only been available to people with access to large amounts of storage, bandwidth, and computing power. Technical discussion points will include: The differences between staging data for analysis using object storage versus file storage Using object stores to design simple RESTful APIs through thoughtful file naming conventions, header fields, and HTTP Range Requests Managing costs through data architecture and Amazon S3's "requester pays" feature Building tools that allow users to take their algorithm to the data in the cloud Using serverless technologies to display dynamic frontends for massive data sets

Ifcwall Reconstruction from Unstructured Point Clouds

Science.gov (United States)

Bassier, M.; Klein, R.; Van Genechten, B.; Vergauwen, M.

2018-05-01

The automated reconstruction of Building Information Modeling (BIM) objects from point cloud data is still ongoing research. A key aspect is the creation of accurate wall geometry as it forms the basis for further reconstruction of objects in a BIM. After segmenting and classifying the initial point cloud, the labelled segments are processed and the wall topology is reconstructed. However, the preocedure is challenging due to noise, occlusions and the complexity of the input data.In this work, a method is presented to automatically reconstruct consistent wall geometry from point clouds. More specifically, the use of room information is proposed to aid the wall topology creation. First, a set of partial walls is constructed based on classified planar primitives. Next, the rooms are identified using the retrieved wall information along with the floors and ceilings. The wall topology is computed by the intersection of the partial walls conditioned on the room information. The final wall geometry is defined by creating IfcWallStandardCase objects conform the IFC4 standard. The result is a set of walls according to the as-built conditions of a building. The experiments prove that the used method is a reliable framework for wall reconstruction from unstructured point cloud data. Also, the implementation of room information reduces the rate of false positives for the wall topology. Given the walls, ceilings and floors, 94% of the rooms is correctly identified. A key advantage of the proposed method is that it deals with complex rooms and is not bound to single storeys.

QUASI-STELLAR OBJECT SELECTION ALGORITHM USING TIME VARIABILITY AND MACHINE LEARNING: SELECTION OF 1620 QUASI-STELLAR OBJECT CANDIDATES FROM MACHO LARGE MAGELLANIC CLOUD DATABASE

International Nuclear Information System (INIS)

Kim, Dae-Won; Protopapas, Pavlos; Alcock, Charles; Trichas, Markos; Byun, Yong-Ik; Khardon, Roni

2011-01-01

We present a new quasi-stellar object (QSO) selection algorithm using a Support Vector Machine, a supervised classification method, on a set of extracted time series features including period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars, and microlensing events using 58 known QSOs, 1629 variable stars, and 4288 non-variables in the MAssive Compact Halo Object (MACHO) database as a training set. To estimate the efficiency and the accuracy of the model, we perform a cross-validation test using the training set. The test shows that the model correctly identifies ∼80% of known QSOs with a 25% false-positive rate. The majority of the false positives are Be stars. We applied the trained model to the MACHO Large Magellanic Cloud (LMC) data set, which consists of 40 million light curves, and found 1620 QSO candidates. During the selection none of the 33,242 known MACHO variables were misclassified as QSO candidates. In order to estimate the true false-positive rate, we crossmatched the candidates with astronomical catalogs including the Spitzer Surveying the Agents of a Galaxy's Evolution LMC catalog and a few X-ray catalogs. The results further suggest that the majority of the candidates, more than 70%, are QSOs.

New Herbig-Haro objects in star-forming regions

Science.gov (United States)

Reipurth, BO; Graham, J. A.

1988-01-01

A list of 25 new Herbig-Haro objects, HH 58 to HH 82, in the Orion molecular clouds and in southern molecular cloud complexes has been compiled. CCD images in the S II 6717, 6731 forbidden lines are presented for the objects, together with a few spectra and some IR observations. The individual objects and, when identified, their energy sources are discussed. HH 65 is located in the red lobe of the bipolar outflow associated with the highly variable reflection nebula Re 50. HH 67 is a 22-arcsec long sinusoidal jet. HH 68/69 consists of a long, linear chain of four HH knots. HH 72 emerges from a 120-solar luminosity IRAS source embedded in a Bok globule. HH 79 is the first HH object discovered in the Ophiuchus clouds. HH 80/81 in Sagittarius are among the brightest HH objects known, have complex velocities, high excitation conditions and emerge from a 6000-solar luminosity young B-star. HH 82 is associated with the bright variable star S Coronae Australis.

Towards Successful Cloud Ordering Service

Directory of Open Access Journals (Sweden)

Chen Yan-Kwang

2015-03-01

Full Text Available Background: The rise of cloud services has led to a drastic growth of e-commerce and a greater investment in development of new cloud services systems by related industries. For SaaS developers, it is important to understand customer needs and make use of available resources at as early as the system design and development stage. Objectives: This study integrates E-commerce Systems (ECS Success model and Importance-Performance Analysis (IPA into empirical research of the critical factors for cloud ordering system success. Methods/Approach: A survey research is conducted to collect data on customer perceptions of the importance and performance of each attribute of the particular cloud ordering service. The sample is further divided according to the degree of use of online shopping into high-usage users and low-usage users in order to explore their views regarding the system and generate adequate coping strategies. Results: Developers of online ordering systems can refer to the important factors obtained in this study when planning strategies of product/service improvement. Conclusions: The approach proposed in this study can also be applied to evaluation of other kinds of cloud services systems.

Scheduling multimedia services in cloud computing environment

Science.gov (United States)

Liu, Yunchang; Li, Chunlin; Luo, Youlong; Shao, Yanling; Zhang, Jing

2018-02-01

Currently, security is a critical factor for multimedia services running in the cloud computing environment. As an effective mechanism, trust can improve security level and mitigate attacks within cloud computing environments. Unfortunately, existing scheduling strategy for multimedia service in the cloud computing environment do not integrate trust mechanism when making scheduling decisions. In this paper, we propose a scheduling scheme for multimedia services in multi clouds. At first, a novel scheduling architecture is presented. Then, We build a trust model including both subjective trust and objective trust to evaluate the trust degree of multimedia service providers. By employing Bayesian theory, the subjective trust degree between multimedia service providers and users is obtained. According to the attributes of QoS, the objective trust degree of multimedia service providers is calculated. Finally, a scheduling algorithm integrating trust of entities is proposed by considering the deadline, cost and trust requirements of multimedia services. The scheduling algorithm heuristically hunts for reasonable resource allocations and satisfies the requirement of trust and meets deadlines for the multimedia services. Detailed simulated experiments demonstrate the effectiveness and feasibility of the proposed trust scheduling scheme.

+Cloud: An Agent-Based Cloud Computing Platform

OpenAIRE

González, Roberto; Hernández de la Iglesia, Daniel; de la Prieta Pintado, Fernando; Gil González, Ana Belén

2017-01-01

Cloud computing is revolutionizing the services provided through the Internet, and is continually adapting itself in order to maintain the quality of its services. This study presents the platform +Cloud, which proposes a cloud environment for storing information and files by following the cloud paradigm. This study also presents Warehouse 3.0, a cloud-based application that has been developed to validate the services provided by +Cloud.

Radiation-hydrodynamics of HII regions and molecular clouds

International Nuclear Information System (INIS)

Sandford, M.T. II; Whitaker, R.W.; Klein, R.I.

1981-01-01

Two-dimensional calculations of ionization-shock fronts surrounding neutral cloud clumps reveal that a radiation-driven implosion of the clump can occur. The implosion of a cloud clump results in the formation of density enhancements that may eventually form low mass stars. The smaller globules produced may become Herbig-Haro objects, or maser sources

Virtual Replication of IoT Hubs in the Cloud: A Flexible Approach to Smart Object Management

Directory of Open Access Journals (Sweden)

Simone Cirani

2018-03-01

Full Text Available In future years, the Internet of Things is expected to interconnect billions of highly heterogeneous devices, denoted as “smart objects”, enabling the development of innovative distributed applications. Smart objects are constrained sensor/actuator-equipped devices, in terms of computational power and available memory. In order to cope with the diverse physical connectivity technologies of smart objects, the Internet Protocol is foreseen as the common “language” for full interoperability and as a unifying factor for integration with the Internet. Large-scale platforms for interconnected devices are required to effectively manage resources provided by smart objects. In this work, we present a novel architecture for the management of large numbers of resources in a scalable, seamless, and secure way. The proposed architecture is based on a network element, denoted as IoT Hub, placed at the border of the constrained network, which implements the following functions: service discovery; border router; HTTP/Constrained Application Protocol (CoAP and CoAP/CoAP proxy; cache; and resource directory. In order to protect smart objects (which cannot, because of their constrained nature, serve a large number of concurrent requests and the IoT Hub (which serves as a gateway to the constrained network, we introduce the concept of virtual IoT Hub replica: a Cloud-based “entity” replicating all the functions of a physical IoT Hub, which external clients will query to access resources. IoT Hub replicas are constantly synchronized with the physical IoT Hub through a low-overhead protocol based on Message Queue Telemetry Transport (MQTT. An experimental evaluation, proving the feasibility and advantages of the proposed architecture, is presented.

Guidelines for Building a Private Cloud Infrastructure

DEFF Research Database (Denmark)

Ali Babar, Muhammad; Pantić, Zoran

on open source software. One of the key objectives of this project was to create relevant material for providing a reference guide on the use of open source software for designing and implementing a private cloud. The primary focus on this document is to provide a brief background on different theoretical......, and a view on the different aspects of cloud computing in this document. Defining the cloud computing; analysis of the economical, security, legality, privacy, confidentiality aspects. There is also a short discussion about the potential impact on the employee’s future roles, and the challenges of migrating...... to a private cloud. The management of the instances and the related subjects are out of the scope of this document. This document is accompanied by three supplemental books that contain material from our experiences of scaling out in the virtual environment and cloud implementation in a physical environment...

Utilizing HDF4 File Content Maps for the Cloud

Science.gov (United States)

Lee, Hyokyung Joe

2016-01-01

We demonstrate a prototype study that HDF4 file content map can be used for efficiently organizing data in cloud object storage system to facilitate cloud computing. This approach can be extended to any binary data formats and to any existing big data analytics solution powered by cloud computing because HDF4 file content map project started as long term preservation of NASA data that doesn't require HDF4 APIs to access data.

Security Techniques for protecting data in Cloud Computing

OpenAIRE

Maddineni, Venkata Sravan Kumar; Ragi, Shivashanker

2012-01-01

Context: From the past few years, there has been a rapid progress in Cloud Computing. With the increasing number of companies resorting to use resources in the Cloud, there is a necessity for protecting the data of various users using centralized resources. Some major challenges that are being faced by Cloud Computing are to secure, protect and process the data which is the property of the user. Aims and Objectives: The main aim of this research is to understand the security threats and ident...

THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. II. THE SPATIAL DISTRIBUTION AND DEMOGRAPHICS OF DUSTY YOUNG STELLAR OBJECTS

International Nuclear Information System (INIS)

Megeath, S. T.; Kryukova, E.; Gutermuth, R.; Muzerolle, J.; Hora, J. L.; Myers, P. C.; Fazio, G. G.; Allen, L. E.; Flaherty, K.; Hartmann, L.; Pipher, J. L.; Stauffer, J.; Young, E. T.

2016-01-01

We analyze the spatial distribution of dusty young stellar objects (YSOs) identified in the Spitzer Survey of the Orion Molecular clouds, augmenting these data with Chandra X-ray observations to correct for incompleteness in dense clustered regions. We also devise a scheme to correct for spatially varying incompleteness when X-ray data are not available. The local surface densities of the YSOs range from 1 pc −2 to over 10,000 pc −2 , with protostars tending to be in higher density regions. This range of densities is similar to other surveyed molecular clouds with clusters, but broader than clouds without clusters. By identifying clusters and groups as continuous regions with surface densities ≥10 pc −2 , we find that 59% of the YSOs are in the largest cluster, the Orion Nebula Cluster (ONC), while 13% of the YSOs are found in a distributed population. A lower fraction of protostars in the distributed population is evidence that it is somewhat older than the groups and clusters. An examination of the structural properties of the clusters and groups shows that the peak surface densities of the clusters increase approximately linearly with the number of members. Furthermore, all clusters with more than 70 members exhibit asymmetric and/or highly elongated structures. The ONC becomes azimuthally symmetric in the inner 0.1 pc, suggesting that the cluster is only ∼2 Myr in age. We find that the star formation efficiency (SFE) of the Orion B cloud is unusually low, and that the SFEs of individual groups and clusters are an order of magnitude higher than those of the clouds. Finally, we discuss the relationship between the young low mass stars in the Orion clouds and the Orion OB 1 association, and we determine upper limits to the fraction of disks that may be affected by UV radiation from OB stars or dynamical interactions in dense, clustered regions

Determining Best Estimates and Uncertainties in Cloud Microphysical Parameters from ARM Field Data: Implications for Models, Retrieval Schemes and Aerosol-Cloud-Radiation Interactions

Energy Technology Data Exchange (ETDEWEB)

McFarquhar, Greg [Univ. of Illinois, Urbana, IL (United States)

2015-12-28

We proposed to analyze in-situ cloud data collected during ARM/ASR field campaigns to create databases of cloud microphysical properties and their uncertainties as needed for the development of improved cloud parameterizations for models and remote sensing retrievals, and for evaluation of model simulations and retrievals. In particular, we proposed to analyze data collected over the Southern Great Plains (SGP) during the Mid-latitude Continental Convective Clouds Experiment (MC3E), the Storm Peak Laboratory Cloud Property Validation Experiment (STORMVEX), the Small Particles in Cirrus (SPARTICUS) Experiment and the Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign, over the North Slope of Alaska during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) and the Mixed-Phase Arctic Cloud Experiment (M-PACE), and over the Tropical Western Pacific (TWP) during The Tropical Warm Pool International Cloud Experiment (TWP-ICE), to meet the following 3 objectives; derive statistical databases of single ice particle properties (aspect ratio AR, dominant habit, mass, projected area) and distributions of ice crystals (size distributions SDs, mass-dimension m-D, area-dimension A-D relations, mass-weighted fall speeds, single-scattering properties, total concentrations N, ice mass contents IWC), complete with uncertainty estimates; assess processes by which aerosols modulate cloud properties in arctic stratus and mid-latitude cumuli, and quantify aerosol’s influence in context of varying meteorological and surface conditions; and determine how ice cloud microphysical, single-scattering and fall-out properties and contributions of small ice crystals to such properties vary according to location, environment, surface, meteorological and aerosol conditions, and develop parameterizations of such effects.In this report we describe the accomplishments that we made on all 3 research objectives.

Silicon Photonics Cloud (SiCloud)

DEFF Research Database (Denmark)

DeVore, P. T. S.; Jiang, Y.; Lynch, M.

2015-01-01

Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

Cloud Processed CCN Suppress Stratus Cloud Drizzle

Science.gov (United States)

Hudson, J. G.; Noble, S. R., Jr.

2017-12-01

Conversion of sulfur dioxide to sulfate within cloud droplets increases the sizes and decreases the critical supersaturation, Sc, of cloud residual particles that had nucleated the droplets. Since other particles remain at the same sizes and Sc a size and Sc gap is often observed. Hudson et al. (2015) showed higher cloud droplet concentrations (Nc) in stratus clouds associated with bimodal high-resolution CCN spectra from the DRI CCN spectrometer compared to clouds associated with unimodal CCN spectra (not cloud processed). Here we show that CCN spectral shape (bimodal or unimodal) affects all aspects of stratus cloud microphysics and drizzle. Panel A shows mean differential cloud droplet spectra that have been divided according to traditional slopes, k, of the 131 measured CCN spectra in the Marine Stratus/Stratocumulus Experiment (MASE) off the Central California coast. K is generally high within the supersaturation, S, range of stratus clouds (< 0.5%). Because cloud processing decreases Sc of some particles, it reduces k. Panel A shows higher concentrations of small cloud droplets apparently grown on lower k CCN than clouds grown on higher k CCN. At small droplet sizes the concentrations follow the k order of the legend, black, red, green, blue (lowest to highest k). Above 13 µm diameter the lines cross and the hierarchy reverses so that blue (highest k) has the highest concentrations followed by green, red and black (lowest k). This reversed hierarchy continues into the drizzle size range (panel B) where the most drizzle drops, Nd, are in clouds grown on the least cloud-processed CCN (blue), while clouds grown on the most processed CCN (black) have the lowest Nd. Suppression of stratus cloud drizzle by cloud processing is an additional 2nd indirect aerosol effect (IAE) that along with the enhancement of 1st IAE by higher Nc (panel A) are above and beyond original IAE. However, further similar analysis is needed in other cloud regimes to determine if MASE was

A PATCHY CLOUD MODEL FOR THE L TO T DWARF TRANSITION

International Nuclear Information System (INIS)

Marley, Mark S.; Saumon, Didier; Goldblatt, Colin

2010-01-01

One mechanism suggested for the L to T dwarf spectral type transition is the appearance of relatively cloud-free regions across the disk of brown dwarfs as they cool. The existence of partly cloudy regions has been supported by evidence for variability in dwarfs in the late L to early T spectral range, but no self-consistent atmosphere models of such partly cloudy objects have yet been constructed. Here, we present a new approach for consistently modeling partly cloudy brown dwarfs and giant planets. We find that even a small fraction of cloud holes dramatically alter the atmospheric thermal profile, spectra, and photometric colors of a given object. With decreasing cloudiness objects briskly become bluer in J - K and brighten in J band, as is observed at the L/T transition. Model spectra of partly cloudy objects are similar to our models with globally homogenous, but thinner, clouds. Hence, spectra alone may not be sufficient to distinguish partial cloudiness although variability and polarization measurements are potential observational signatures. Finally, we note that partial cloud cover may be an alternative explanation for the blue L dwarfs.

Herbig-Haro objects

International Nuclear Information System (INIS)

Schwartz, R.D.

1983-01-01

Progress in the understanding of Herbig-Haro (HH) objects is reviewed. The results of optical studies of the proper motions and alignments, variability, and polarization of HH objects and the results of spectroscopic studies are discussed. Ground-based infrared studies and far-infrared observations are reviewed. Findings on the properties of molecular clouds associated with HH objects, on gas flows associated with HH IR stars, on maser emission, and on radio continuum observations are considered. A history of proposed excitation mechanisms for HH objects is briefly presented, and the salient shock-wave calculations aimed at synthesizing the spectra of HH objects are summarized along with hypotheses that have been advanced about the origin of the objects. 141 references

Cloud vertical profiles derived from CALIPSO and CloudSat and a comparison with MODIS derived clouds

Science.gov (United States)

Kato, S.; Sun-Mack, S.; Miller, W. F.; Rose, F. G.; Minnis, P.; Wielicki, B. A.; Winker, D. M.; Stephens, G. L.; Charlock, T. P.; Collins, W. D.; Loeb, N. G.; Stackhouse, P. W.; Xu, K.

2008-05-01

CALIPSO and CloudSat from the a-train provide detailed information of vertical distribution of clouds and aerosols. The vertical distribution of cloud occurrence is derived from one month of CALIPSO and CloudSat data as a part of the effort of merging CALIPSO, CloudSat and MODIS with CERES data. This newly derived cloud profile is compared with the distribution of cloud top height derived from MODIS on Aqua from cloud algorithms used in the CERES project. The cloud base from MODIS is also estimated using an empirical formula based on the cloud top height and optical thickness, which is used in CERES processes. While MODIS detects mid and low level clouds over the Arctic in April fairly well when they are the topmost cloud layer, it underestimates high- level clouds. In addition, because the CERES-MODIS cloud algorithm is not able to detect multi-layer clouds and the empirical formula significantly underestimates the depth of high clouds, the occurrence of mid and low-level clouds is underestimated. This comparison does not consider sensitivity difference to thin clouds but we will impose an optical thickness threshold to CALIPSO derived clouds for a further comparison. The effect of such differences in the cloud profile to flux computations will also be discussed. In addition, the effect of cloud cover to the top-of-atmosphere flux over the Arctic using CERES SSF and FLASHFLUX products will be discussed.

Overview of the CERES Edition-4 Multilayer Cloud Property Datasets

Science.gov (United States)

Chang, F. L.; Minnis, P.; Sun-Mack, S.; Chen, Y.; Smith, R. A.; Brown, R. R.

2014-12-01

Knowledge of the cloud vertical distribution is important for understanding the role of clouds on earth's radiation budget and climate change. Since high-level cirrus clouds with low emission temperatures and small optical depths can provide a positive feedback to a climate system and low-level stratus clouds with high emission temperatures and large optical depths can provide a negative feedback effect, the retrieval of multilayer cloud properties using satellite observations, like Terra and Aqua MODIS, is critically important for a variety of cloud and climate applications. For the objective of the Clouds and the Earth's Radiant Energy System (CERES), new algorithms have been developed using Terra and Aqua MODIS data to allow separate retrievals of cirrus and stratus cloud properties when the two dominant cloud types are simultaneously present in a multilayer system. In this paper, we will present an overview of the new CERES Edition-4 multilayer cloud property datasets derived from Terra as well as Aqua. Assessment of the new CERES multilayer cloud datasets will include high-level cirrus and low-level stratus cloud heights, pressures, and temperatures as well as their optical depths, emissivities, and microphysical properties.

COLOR SYSTEMATICS OF COMETS AND RELATED BODIES

Energy Technology Data Exchange (ETDEWEB)

Jewitt, David, E-mail: jewitt@ucla.edu [Department of Earth, Planetary and Space Sciences, UCLA, 595 Charles Young Drive East, Los Angeles, CA 90095-1567 (United States)

2015-12-15

Most comets are volatile-rich bodies that have recently entered the inner solar system following long-term storage in the Kuiper belt and the Oort cloud reservoirs. These reservoirs feed several distinct, short-lived “small body” populations. Here, we present new measurements of the optical colors of cometary and comet-related bodies including long-period (Oort cloud) comets, Damocloids (probable inactive nuclei of long-period comets) and Centaurs (recent escapees from the Kuiper belt and precursors to the Jupiter family comets). We combine the new measurements with published data on short-period comets, Jovian Trojans and Kuiper belt objects to examine the color systematics of the comet-related populations. We find that the mean optical colors of the dust in short-period and long-period comets are identical within the uncertainties of measurement, as are the colors of the dust and of the underlying nuclei. These populations show no evidence for scattering by optically small particles or for compositional gradients, even at the largest distances from the Sun, and no evidence for ultrared matter. Consistent with earlier work, ultrared surfaces are common in the Kuiper belt and on the Centaurs, but not in other small body populations, suggesting that this material is hidden or destroyed upon entry to the inner solar system. The onset of activity in the Centaurs and the disappearance of the ultrared matter in this population begin at about the same perihelion distance (∼10 AU), suggesting that the two are related. Blanketing of primordial surface materials by the fallback of sub-orbital ejecta, for which we calculate a very short timescale, is the likely mechanism. The same process should operate on any mass-losing body, explaining the absence of ultrared surface material in the entire comet population.

Molecular clouds and galactic spiral structure

International Nuclear Information System (INIS)

Dame, T.M.

1984-02-01

Galactic CO line emission at 115 GHz was surveyed in order to study the distribution of molecular clouds in the inner galaxy. Comparison of this survey with similar H1 data reveals a detailed correlation with the most intense 21 cm features. To each of the classical 21 cm H1 spiral arms of the inner galaxy there corresponds a CO molecular arm which is generally more clearly defined and of higher contrast. A simple model is devised for the galactic distribution of molecular clouds. The modeling results suggest that molecular clouds are essentially transient objects, existing for 15 to 40 million years after their formation in a spiral arm, and are largely confined to spiral features about 300 pc wide

Evaluation results of the optimal estimation based, multi-sensor cloud property data sets derived from AVHRR heritage measurements in the Cloud_cci project.

Science.gov (United States)

Stapelberg, S.; Jerg, M.; Stengel, M.; Hollmann, R.

2014-12-01

In 2010 the ESA Climate Change Initiative (CCI) Cloud project was started with the objectives of generating a long-term coherent data set of cloud properties. The cloud properties considered are cloud mask, cloud top estimates, cloud optical thickness, cloud effective radius and post processed parameters such as cloud liquid and ice water path. During the first phase of the project 3 years of data spanning 2007 to 2009 have been produced on a global gridded daily and monthly mean basis. Next to the processing an extended evaluation study was started in order to gain a first understanding of the quality of the retrieved data. The critical discussion of the results of the evaluation holds a key role for the further development and improvement of the dataset's quality. The presentation will give a short overview of the evaluation study undertaken in the Cloud_cci project. The focus will be on the evaluation of gridded, monthly mean cloud fraction and cloud top data from the Cloud_cci AVHRR-heritage dataset with CLARA-A1, MODIS-Coll5, PATMOS-X and ISCCP data. Exemplary results will be shown. Strengths and shortcomings of the retrieval scheme as well as possible impacts of averaging approaches on the evaluation will be discussed. An Overview of Cloud_cci Phase 2 will be given.

A peculiar Herbig-Haro object located far outside Lynds 1641

International Nuclear Information System (INIS)

Ogura, Katsuo

1991-01-01

A peculiar Herbig-Haro object, named HH 131, has been discovered by low-dispersion slit spectroscopy and narrowband CCD imaging. It lies well outside the dark cloud Lynds (L) 1641 toward the southwest. Accordingly, it has no associated molecular cloud, but it may be related to a cloud of atomic hydrogen. Its morphology is also unique, showing a fairly high degree of axisymmetric structure as well as a sort of double helix. No likely candidates for its energy source have been found in the IRAS Point Source Catalog, or by slit spectroscopy and an objective-prism Schmidt survey of nearby stars. 24 refs

Electrical discharge occurring between a negatively charged particle cloud and a grounded sphere electrode

International Nuclear Information System (INIS)

Higashiyama, Y; Migita, S; Toki, K; Sugimoto, T

2008-01-01

Electrostatic discharge occurring between a space-charge cloud and a grounded object was investigated using a large-scale charged particle cloud formed by using three set of cloud generators consisting of a blower and corona charger. The ejecting velocity of the particles affects the formation of the charged cloud. At the lower velocity, the charged cloud spread due to electrostatic repulsion force, while at the higher velocity cloud forms an elongated conical shape. To cause electrostatic discharge between the cloud and a grounded object, a grounded sphere electrode with 100 mm in diameter was set at the inside or outside of the cloud. The brush-like discharge channels reached the maximum length of 0.55 m. The discharge current has a waveform with single or multi-peak, a current peak of several amperes, the maximum charge quantity of 2 μC, and the duration of several microseconds. The relationship between the charge quantity and the current peak or the duration in each discharge was examined. The discharge between the cloud and the electrode placed at the outside of the cloud has relatively longer channels and multi-peak current with the longer duration, while that at the inside of the cloud has the lower charge quantity with single peak.

Cloud Computing and Its Applications in GIS

Science.gov (United States)

Kang, Cao

2011-12-01

Cloud computing is a novel computing paradigm that offers highly scalable and highly available distributed computing services. The objectives of this research are to: 1. analyze and understand cloud computing and its potential for GIS; 2. discover the feasibilities of migrating truly spatial GIS algorithms to distributed computing infrastructures; 3. explore a solution to host and serve large volumes of raster GIS data efficiently and speedily. These objectives thus form the basis for three professional articles. The first article is entitled "Cloud Computing and Its Applications in GIS". This paper introduces the concept, structure, and features of cloud computing. Features of cloud computing such as scalability, parallelization, and high availability make it a very capable computing paradigm. Unlike High Performance Computing (HPC), cloud computing uses inexpensive commodity computers. The uniform administration systems in cloud computing make it easier to use than GRID computing. Potential advantages of cloud-based GIS systems such as lower barrier to entry are consequently presented. Three cloud-based GIS system architectures are proposed: public cloud- based GIS systems, private cloud-based GIS systems and hybrid cloud-based GIS systems. Public cloud-based GIS systems provide the lowest entry barriers for users among these three architectures, but their advantages are offset by data security and privacy related issues. Private cloud-based GIS systems provide the best data protection, though they have the highest entry barriers. Hybrid cloud-based GIS systems provide a compromise between these extremes. The second article is entitled "A cloud computing algorithm for the calculation of Euclidian distance for raster GIS". Euclidean distance is a truly spatial GIS algorithm. Classical algorithms such as the pushbroom and growth ring techniques require computational propagation through the entire raster image, which makes it incompatible with the distributed nature

A study on strategic provisioning of cloud computing services.

Science.gov (United States)

Whaiduzzaman, Md; Haque, Mohammad Nazmul; Rejaul Karim Chowdhury, Md; Gani, Abdullah

2014-01-01

Cloud computing is currently emerging as an ever-changing, growing paradigm that models "everything-as-a-service." Virtualised physical resources, infrastructure, and applications are supplied by service provisioning in the cloud. The evolution in the adoption of cloud computing is driven by clear and distinct promising features for both cloud users and cloud providers. However, the increasing number of cloud providers and the variety of service offerings have made it difficult for the customers to choose the best services. By employing successful service provisioning, the essential services required by customers, such as agility and availability, pricing, security and trust, and user metrics can be guaranteed by service provisioning. Hence, continuous service provisioning that satisfies the user requirements is a mandatory feature for the cloud user and vitally important in cloud computing service offerings. Therefore, we aim to review the state-of-the-art service provisioning objectives, essential services, topologies, user requirements, necessary metrics, and pricing mechanisms. We synthesize and summarize different provision techniques, approaches, and models through a comprehensive literature review. A thematic taxonomy of cloud service provisioning is presented after the systematic review. Finally, future research directions and open research issues are identified.

A Study on Strategic Provisioning of Cloud Computing Services

Directory of Open Access Journals (Sweden)

Md Whaiduzzaman

2014-01-01

Full Text Available Cloud computing is currently emerging as an ever-changing, growing paradigm that models “everything-as-a-service.” Virtualised physical resources, infrastructure, and applications are supplied by service provisioning in the cloud. The evolution in the adoption of cloud computing is driven by clear and distinct promising features for both cloud users and cloud providers. However, the increasing number of cloud providers and the variety of service offerings have made it difficult for the customers to choose the best services. By employing successful service provisioning, the essential services required by customers, such as agility and availability, pricing, security and trust, and user metrics can be guaranteed by service provisioning. Hence, continuous service provisioning that satisfies the user requirements is a mandatory feature for the cloud user and vitally important in cloud computing service offerings. Therefore, we aim to review the state-of-the-art service provisioning objectives, essential services, topologies, user requirements, necessary metrics, and pricing mechanisms. We synthesize and summarize different provision techniques, approaches, and models through a comprehensive literature review. A thematic taxonomy of cloud service provisioning is presented after the systematic review. Finally, future research directions and open research issues are identified.

FPFH-based graph matching for 3D point cloud registration

Science.gov (United States)

Zhao, Jiapeng; Li, Chen; Tian, Lihua; Zhu, Jihua

2018-04-01

Correspondence detection is a vital step in point cloud registration and it can help getting a reliable initial alignment. In this paper, we put forward an advanced point feature-based graph matching algorithm to solve the initial alignment problem of rigid 3D point cloud registration with partial overlap. Specifically, Fast Point Feature Histograms are used to determine the initial possible correspondences firstly. Next, a new objective function is provided to make the graph matching more suitable for partially overlapping point cloud. The objective function is optimized by the simulated annealing algorithm for final group of correct correspondences. Finally, we present a novel set partitioning method which can transform the NP-hard optimization problem into a O(n3)-solvable one. Experiments on the Stanford and UWA public data sets indicates that our method can obtain better result in terms of both accuracy and time cost compared with other point cloud registration methods.

A survey of IoT cloud platforms

Directory of Open Access Journals (Sweden)

Partha Pratim Ray

2016-12-01

Full Text Available Internet of Things (IoT envisages overall merging of several “things” while utilizing internet as the backbone of the communication system to establish a smart interaction between people and surrounding objects. Cloud, being the crucial component of IoT, provides valuable application specific services in many application domains. A number of IoT cloud providers are currently emerging into the market to leverage suitable and specific IoT based services. In spite of huge possible involvement of these IoT clouds, no standard cum comparative analytical study has been found across the literature databases. This article surveys popular IoT cloud platforms in light of solving several service domains such as application development, device management, system management, heterogeneity management, data management, tools for analysis, deployment, monitoring, visualization, and research. A comparison is presented for overall dissemination of IoT clouds according to their applicability. Further, few challenges are also described that the researchers should take on in near future. Ultimately, the goal of this article is to provide detailed knowledge about the existing IoT cloud service providers and their pros and cons in concrete form.

D1.1 Research communities identification and definition report : Europeana Cloud: Unlocking Europe’s Research via The Cloud; WP1

NARCIS (Netherlands)

Waterman, MA Kees-Jan; Links, P.; Ekman, Stefan; Sjögren, Björn; Benardou, Agiatis

Europeana Cloud’s main objectives are to provide new content, new metadata, a new linked storage system, new tools and services for researchers and a new platform, Europeana Research. For Europeana Cloud to achieve these objectives, it is essential that researchers’ needs are thoroughly understood.

The Impact of Cloud Computing Technologies in E-learning

Directory of Open Access Journals (Sweden)

Hosam Farouk El-Sofany

2013-01-01

Full Text Available Cloud computing is a new computing model which is based on the grid computing, distributed computing, parallel computing and virtualization technologies define the shape of a new technology. It is the core technology of the next generation of network computing platform, especially in the field of education, cloud computing is the basic environment and platform of the future E-learning. It provides secure data storage, convenient internet services and strong computing power. This article mainly focuses on the research of the application of cloud computing in E-learning environment. The research study shows that the cloud platform is valued for both students and instructors to achieve the course objective. The paper presents the nature, benefits and cloud computing services, as a platform for e-learning environment.

Colliding clouds and star formation in NGC 1333

International Nuclear Information System (INIS)

Loren, R.B.

1976-01-01

Ongoing star formation in the NGC 1333 molecular cloud is found to be the result of a cloud-cloud collision. Two velocity components at 6.3 and 8.3 km s -1 are observable in the CO and 13 CO spectra, with strong self-abosorption occurring only in the 8.3 km s -1 component. The cloud-cloud collision provides compression and heating of the back side of the 8.3 km s -1 cloud, while cool, unshocked gas on the front side of this cloud results in the observed self-absorption. With the 6.3 km s -1 cloud on the far side of the collision interface, no self-absorption occurs at this velocity. One result of the collision is the coalescence of the two velocity components into a single, intermediate velocity component observed at 7.5 km s -1 . Associated with this postcollision gas is a chain of newly formed stars which illuminates and heats the nebulosity of NGC 1333.At one end of this chain of stars is a region of enhanced CO line broadening, indicating a nonhomologous gravitational collapse of this portion of the cloud. The infrared stars closest to the part of the cloud which is collapsing are completely obscured at visual wavelengths, and several are associated with Herbig-Haro (HH) objects. With increasing displacement from the region of collapse, the stars become more visible, are probably older, and the CO self-absorption decreases at these positions in the cloud.The observed region in which the cloud-cloud collision is occurring is located at the intersection of an expanding neutral hydrogen shell and lower-velocity background H I

Stratocumulus Cloud Top Radiative Cooling and Cloud Base Updraft Speeds

Science.gov (United States)

Kazil, J.; Feingold, G.; Balsells, J.; Klinger, C.

2017-12-01

Cloud top radiative cooling is a primary driver of turbulence in the stratocumulus-topped marine boundary. A functional relationship between cloud top cooling and cloud base updraft speeds may therefore exist. A correlation of cloud top radiative cooling and cloud base updraft speeds has been recently identified empirically, providing a basis for satellite retrieval of cloud base updraft speeds. Such retrievals may enable analysis of aerosol-cloud interactions using satellite observations: Updraft speeds at cloud base co-determine supersaturation and therefore the activation of cloud condensation nuclei, which in turn co-determine cloud properties and precipitation formation. We use large eddy simulation and an off-line radiative transfer model to explore the relationship between cloud-top radiative cooling and cloud base updraft speeds in a marine stratocumulus cloud over the course of the diurnal cycle. We find that during daytime, at low cloud water path (CWP correlated, in agreement with the reported empirical relationship. During the night, in the absence of short-wave heating, CWP builds up (CWP > 50 g m-2) and long-wave emissions from cloud top saturate, while cloud base heating increases. In combination, cloud top cooling and cloud base updrafts become weakly anti-correlated. A functional relationship between cloud top cooling and cloud base updraft speed can hence be expected for stratocumulus clouds with a sufficiently low CWP and sub-saturated long-wave emissions, in particular during daytime. At higher CWPs, in particular at night, the relationship breaks down due to saturation of long-wave emissions from cloud top.

THE EVOLUTION OF GAS CLOUDS FALLING IN THE MAGNETIZED GALACTIC HALO: HIGH-VELOCITY CLOUDS (HVCs) ORIGINATED IN THE GALACTIC FOUNTAIN

International Nuclear Information System (INIS)

Kwak, Kyujin; Shelton, Robin L.; Raley, Elizabeth A.

2009-01-01

In the Galactic fountain scenario, supernovae and/or stellar winds propel material into the Galactic halo. As the material cools, it condenses into clouds. By using FLASH three-dimensional magnetohydrodynamic simulations, we model and study the dynamical evolution of these gas clouds after they form and begin to fall toward the Galactic plane. In our simulations, we assume that the gas clouds form at a height of z = 5 kpc above the Galactic midplane, then begin to fall from rest. We investigate how the cloud's evolution, dynamics, and interaction with the interstellar medium (ISM) are affected by the initial mass of the cloud. We find that clouds with sufficiently large initial densities (n ≥ 0.1 H atoms cm -3 ) accelerate sufficiently and maintain sufficiently large column densities as to be observed and identified as high-velocity clouds (HVCs) even if the ISM is weakly magnetized (1.3 μG). However, the ISM can provide noticeable resistance to the motion of a low-density cloud (n ≤ 0.01 H atoms cm -3 ) thus making it more probable that a low-density cloud will attain the speed of an intermediate-velocity cloud rather than the speed of an HVC. We also investigate the effects of various possible magnetic field configurations. As expected, the ISM's resistance is greatest when the magnetic field is strong and perpendicular to the motion of the cloud. The trajectory of the cloud is guided by the magnetic field lines in cases where the magnetic field is oriented diagonal to the Galactic plane. The model cloud simulations show that the interactions between the cloud and the ISM can be understood via analogy to the shock tube problem which involves shock and rarefaction waves. We also discuss accelerated ambient gas, streamers of material ablated from the clouds, and the cloud's evolution from a sphere-shaped to a disk- or cigar-shaped object.

Secure public cloud platform for medical images sharing.

Science.gov (United States)

Pan, Wei; Coatrieux, Gouenou; Bouslimi, Dalel; Prigent, Nicolas

2015-01-01

Cloud computing promises medical imaging services offering large storage and computing capabilities for limited costs. In this data outsourcing framework, one of the greatest issues to deal with is data security. To do so, we propose to secure a public cloud platform devoted to medical image sharing by defining and deploying a security policy so as to control various security mechanisms. This policy stands on a risk assessment we conducted so as to identify security objectives with a special interest for digital content protection. These objectives are addressed by means of different security mechanisms like access and usage control policy, partial-encryption and watermarking.

Cloud networking understanding cloud-based data center networks

CERN Document Server

Lee, Gary

2014-01-01

Cloud Networking: Understanding Cloud-Based Data Center Networks explains the evolution of established networking technologies into distributed, cloud-based networks. Starting with an overview of cloud technologies, the book explains how cloud data center networks leverage distributed systems for network virtualization, storage networking, and software-defined networking. The author offers insider perspective to key components that make a cloud network possible such as switch fabric technology and data center networking standards. The final chapters look ahead to developments in architectures

Star formation in evolving molecular clouds

Science.gov (United States)

Völschow, M.; Banerjee, R.; Körtgen, B.

2017-09-01

Molecular clouds are the principle stellar nurseries of our universe; they thus remain a focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many questions regarding their evolution and star formation activity remain open. While numerical simulations feature a large number and complexity of involved physical processes, this plethora of effects may hide the fundamentals that determine the evolution of molecular clouds and enable the formation of stars. Purely analytical models, on the other hand, tend to suffer from rough approximations or a lack of completeness, limiting their predictive power. In this paper, we present a model that incorporates central concepts of astrophysics as well as reliable results from recent simulations of molecular clouds and their evolutionary paths. Based on that, we construct a self-consistent semi-analytical framework that describes the formation, evolution, and star formation activity of molecular clouds, including a number of feedback effects to account for the complex processes inside those objects. The final equation system is solved numerically but at much lower computational expense than, for example, hydrodynamical descriptions of comparable systems. The model presented in this paper agrees well with a broad range of observational results, showing that molecular cloud evolution can be understood as an interplay between accretion, global collapse, star formation, and stellar feedback.

Digital Invasions: from Point Clouds to Historical Building Object Modeling H-Bom of a Unesco Whl Site

Science.gov (United States)

Chiabrando, F.; Lo Turco, M.; Santagati, C.

2017-02-01

The paper here presented shows the outcomes of a research/didactic activity carried out within a workshop titled "Digital Invasions. From point cloud to Heritage Building Information Modeling" held at Politecnico di Torino (29th September-5th October 2016). The term digital invasions refers to an Italian bottom up project born in the 2013 with the aim of promoting innovative digital ways for the enhancement of Cultural Heritage by the co-creation of cultural contents and its sharing through social media platforms. At this regard, we have worked with students of Architectural Master of Science degree, training them with a multidisciplinary teaching team (Architectural Representation, History of Architecture, Restoration, Digital Communication and Geomatics). The aim was also to test if our students could be involved in a sort of niche crowdsourcing for the creation of a library of H-BOMS (Historical-Building Object Modeling) of architectural elements.

DIGITAL INVASIONS: FROM POINT CLOUDS TO HISTORICAL BUILDING OBJECT MODELING (H-BOM OF A UNESCO WHL SITE

Directory of Open Access Journals (Sweden)

F. Chiabrando

2017-02-01

Full Text Available The paper here presented shows the outcomes of a research/didactic activity carried out within a workshop titled "Digital Invasions. From point cloud to Heritage Building Information Modeling" held at Politecnico di Torino (29th September–5th October 2016. The term digital invasions refers to an Italian bottom up project born in the 2013 with the aim of promoting innovative digital ways for the enhancement of Cultural Heritage by the co-creation of cultural contents and its sharing through social media platforms. At this regard, we have worked with students of Architectural Master of Science degree, training them with a multidisciplinary teaching team (Architectural Representation, History of Architecture, Restoration, Digital Communication and Geomatics. The aim was also to test if our students could be involved in a sort of niche crowdsourcing for the creation of a library of H-BOMS (Historical-Building Object Modeling of architectural elements.

Considerations about Cloud Services: Learning

Directory of Open Access Journals (Sweden)

Riccardo Cognini

2013-05-01

Full Text Available Cloud services are ubiquitous: for small to large companies the phenomenon of cloud service is nowadays a standard business practice. This paper would compile an analysis over a possible implementation of a cloud system, treating especially the legal aspect of this theme. In the Italian market has a large number of issues arise form cloud computing. First of all, this paper investigates the legal issues associated to cloud computing, specific contractual scheme that is able to define rights a duties both of user (private and/or public body and cloud provider. On one side there is all the EU legislative production related to privacy over electronic communication and, furthermore, the Privacy Directive is under a revision process to be more adaptable to new challenges of decentralized data treatment, but concretely there are no any structured and well defined legal instruments. Objectives: we present a possible solution to address the uncertainty of this area, starting from the EU legislative production with the help of the specific Italian scenario that could offer an operative solution. Indeed the Italian legal system is particularly adaptable to changing technologies and it could use as better as possible to adapt the already existing legal tools to this new technological era. Prior work: after an introduction to the state of the art, we show the main issues and their critical points that must be solved. Approach: observation of the state of the art to propose a new approach to find the suitable disciple

Multi-wavelength study of two possible cloud-cloud collision regions: IRAS 02459+6029 and IRAS 22528+5936

International Nuclear Information System (INIS)

Li Nan; Wang Junjie

2012-01-01

Based on observations of 12 CO (J=2–1), we select targets from archived Infrared Astronomical Satellite (IRAS) data of IRAS 02459+6029 and IRAS 22528+5936 as samples of cloud-cloud collision, according to the criteria given by Vallee. Then we use the Midcourse Space Experiment (MSX) A band (8.28 μm) images and the NRAO VLA Sky Survey (NVSS) (1.4 GHz) continuum images to investigate the association between molecular clouds traced by the CO contour maps. The distribution of dust and ionized hydrogen shows an obvious association with the CO contour maps toward IRAS 02459+6029. However, in the possible collision region of IRAS 22528+5936, NVSS continuum radiation is not detected and the MSX sources are merely associated with the central star. The velocity fields of the two regions indicate the direction of the pressure and interaction. In addition, we have identified candidates of young stellar objects (YSOs) by using data from the Two Micron All Sky Survey (2MASS) in JHK bands expressed in a color-color diagram. The distribution of YSOs shows that the possible collision region is denser than other regions. All the evidence suggests that IRAS 02459+6029 could be an example of cloud-cloud collision, and that IRAS 22528+5936 could be two separate non-colliding clouds. (research papers)

A Classification-oriented Method of Feature Image Generation for Vehicle-borne Laser Scanning Point Clouds

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YANG Bisheng

2016-02-01

Full Text Available An efficient method of feature image generation of point clouds to automatically classify dense point clouds into different categories is proposed, such as terrain points, building points. The method first uses planar projection to sort points into different grids, then calculates the weights and feature values of grids according to the distribution of laser scanning points, and finally generates the feature image of point clouds. Thus, the proposed method adopts contour extraction and tracing means to extract the boundaries and point clouds of man-made objects (e.g. buildings and trees in 3D based on the image generated. Experiments show that the proposed method provides a promising solution for classifying and extracting man-made objects from vehicle-borne laser scanning point clouds.

Formation of giant molecular clouds in global spiral structures: the role of orbital dynamics and cloud-cloud collisions

International Nuclear Information System (INIS)

Roberts, W.W. Jr.; Stewart, G.R.

1987-01-01

The different roles played by orbital dynamics and dissipative cloud-cloud collisions in the formation of giant molecular clouds (GMCs) in a global spiral structure are investigated. The interstellar medium (ISM) is simulated by a system of particles, representing clouds, which orbit in a spiral-perturbed, galactic gravitational field. The overall magnitude and width of the global cloud density distribution in spiral arms is very similar in the collisional and collisionless simulations. The results suggest that the assumed number density and size distribution of clouds and the details of individual cloud-cloud collisions have relatively little effect on these features. Dissipative cloud-cloud collisions play an important steadying role for the cloud system's global spiral structure. Dissipative cloud-cloud collisions also damp the relative velocity dispersion of clouds in massive associations and thereby aid in the effective assembling of GMC-like complexes

Evaluation of Passive Multilayer Cloud Detection Using Preliminary CloudSat and CALIPSO Cloud Profiles

Science.gov (United States)

Minnis, P.; Sun-Mack, S.; Chang, F.; Huang, J.; Nguyen, L.; Ayers, J. K.; Spangenberg, D. A.; Yi, Y.; Trepte, C. R.

2006-12-01

During the last few years, several algorithms have been developed to detect and retrieve multilayered clouds using passive satellite data. Assessing these techniques has been difficult due to the need for active sensors such as cloud radars and lidars that can "see" through different layers of clouds. Such sensors have been available only at a few surface sites and on aircraft during field programs. With the launch of the CALIPSO and CloudSat satellites on April 28, 2006, it is now possible to observe multilayered systems all over the globe using collocated cloud radar and lidar data. As part of the A- Train, these new active sensors are also matched in time ad space with passive measurements from the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer - EOS (AMSR-E). The Clouds and the Earth's Radiant Energy System (CERES) has been developing and testing algorithms to detect ice-over-water overlapping cloud systems and to retrieve the cloud liquid path (LWP) and ice water path (IWP) for those systems. One technique uses a combination of the CERES cloud retrieval algorithm applied to MODIS data and a microwave retrieval method applied to AMSR-E data. The combination of a CO2-slicing cloud retireval technique with the CERES algorithms applied to MODIS data (Chang et al., 2005) is used to detect and analyze such overlapped systems that contain thin ice clouds. A third technique uses brightness temperature differences and the CERES algorithms to detect similar overlapped methods. This paper uses preliminary CloudSat and CALIPSO data to begin a global scale assessment of these different methods. The long-term goals are to assess and refine the algorithms to aid the development of an optimal combination of the techniques to better monitor ice 9and liquid water clouds in overlapped conditions.

Protostellar formation in rotation interstellar clouds. III. Nonaxisymmetric collapse

International Nuclear Information System (INIS)

Boss, A.P.

1980-01-01

A full three spatial-dimension gravitational hydrodynamics code has been used to follow the collapse of isothermal rotating clouds subjected to various nonaxialy symmetric perturbations (NAP). An initially axially symmetric cloud collapsed to form a ring which then fragmented into a binary protostellar system. A low thermal energy cloud with a large bar-shaped NAP collapsed and fragmented directly into a binary; higher thermal energy clouds damp out such NAPs while higher rotational rotational energy clouds produce binaries with wider separations. Fragmentation into single and binary systems has been seen. The tidal effects of other nearby protostellar clouds are shown to have an important effect upon the collapse and should not be neglected. The three-dimensional calculations indicate that isothermal interstellar clouds may fragment (with or without passing through a transitory ring phase) into protostellar objects while still in the isothermal regime. The fragments obtained have masses and specific spin angular momenta roughly a 10th that of the original cloud. Interstellar clouds and their fragments may pass through successive collapse phases with fragmentation and reduction of spin angular momentum (by conversion to orbital angular momentum and preferential accretion of low angular momentum matter) terminating in the formation of pre--main-sequence stars with the observed pre--main-sequence rotation rates

Cloud Computing Fundamentals

Science.gov (United States)

Furht, Borko

In the introductory chapter we define the concept of cloud computing and cloud services, and we introduce layers and types of cloud computing. We discuss the differences between cloud computing and cloud services. New technologies that enabled cloud computing are presented next. We also discuss cloud computing features, standards, and security issues. We introduce the key cloud computing platforms, their vendors, and their offerings. We discuss cloud computing challenges and the future of cloud computing.

Chemical equilibrium models of interstellar gas clouds

International Nuclear Information System (INIS)

Freeman, A.

1982-10-01

This thesis contains work which helps towards our understanding of the chemical processes and astrophysical conditions in interstellar clouds, across the whole range of cloud types. The object of the exercise is to construct a mathematical model representing a large system of two-body chemical reactions in order to deduce astrophysical parameters and predict molecular abundances and chemical pathways. Comparison with observations shows that this type of model is valid but also indicates that our knowledge of some chemical reactions is incomplete. (author)

Multiview 3D sensing and analysis for high quality point cloud reconstruction

Science.gov (United States)

Satnik, Andrej; Izquierdo, Ebroul; Orjesek, Richard

2018-04-01

Multiview 3D reconstruction techniques enable digital reconstruction of 3D objects from the real world by fusing different viewpoints of the same object into a single 3D representation. This process is by no means trivial and the acquisition of high quality point cloud representations of dynamic 3D objects is still an open problem. In this paper, an approach for high fidelity 3D point cloud generation using low cost 3D sensing hardware is presented. The proposed approach runs in an efficient low-cost hardware setting based on several Kinect v2 scanners connected to a single PC. It performs autocalibration and runs in real-time exploiting an efficient composition of several filtering methods including Radius Outlier Removal (ROR), Weighted Median filter (WM) and Weighted Inter-Frame Average filtering (WIFA). The performance of the proposed method has been demonstrated through efficient acquisition of dense 3D point clouds of moving objects.

THE 1.1 mm CONTINUUM SURVEY OF THE SMALL MAGELLANIC CLOUD: PHYSICAL PROPERTIES AND EVOLUTION OF THE DUST-SELECTED CLOUDS

Energy Technology Data Exchange (ETDEWEB)

Takekoshi, Tatsuya; Minamidani, Tetsuhiro; Sorai, Kazuo [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Komugi, Shinya; Muller, Erik; Mizuno, Norikazu; Kawamura, Akiko; Ezawa, Hajime [Chile Observatory, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan); Kohno, Kotaro [Institute of Astronomy, The University of Tokyo, 2-21-1, Osawa, Mitaka, Tokyo 181-0015 (Japan); Tosaki, Tomoka [Joetsu University of Education, Joetsu, Niigata 943-8512 (Japan); Onishi, Toshikazu [Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, Osaka 599-8531 (Japan); Fukui, Yasuo [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Oshima, Tai; Kawabe, Ryohei [Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), 462-2, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Scott, Kimberly S.; Austermann, Jason E.; Wilson, Grant W. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Matsuo, Hiroshi [Department of Astronomical Science, School of Physical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan); Aretxaga, Itziar; Hughes, David H. [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), 72000 Puebla (Mexico); and others

2017-01-20

The first 1.1 mm continuum survey toward the Small Magellanic Cloud (SMC) was performed using the AzTEC instrument installed on the ASTE 10 m telescope. This survey covered 4.5 deg{sup 2} of the SMC with 1 σ noise levels of 5–12 mJy beam{sup −1}, and 44 extended objects were identified. The 1.1 mm extended emission has good spatial correlation with Herschel 160 μ m, indicating that the origin of the 1.1 mm extended emission is thermal emission from a cold dust component. We estimated physical properties using the 1.1 mm and filtered Herschel data (100, 160, 250, 350, and 500 μ m). The 1.1 mm objects show dust temperatures of 17–45 K and gas masses of 4 × 10{sup 3}–3 × 10{sup 5} M {sub ⊙}, assuming single-temperature thermal emission from the cold dust with an emissivity index, β , of 1.2 and a gas-to-dust ratio of 1000. These physical properties are very similar to those of giant molecular clouds (GMCs) in our galaxy and the Large Magellanic Cloud. The 1.1 mm objects also displayed good spatial correlation with the Spitzer 24 μ m and CO emission, suggesting that the 1.1 mm objects trace the dense gas regions as sites of massive star formation. The dust temperature of the 1.1 mm objects also demonstrated good correlation with the 24 μ m flux connected to massive star formation. This supports the hypothesis that the heating source of the cold dust is mainly local star-formation activity in the 1.1 mm objects. The classification of the 1.1 mm objects based on the existence of star-formation activity reveals the differences in the dust temperature, gas mass, and radius, which reflects the evolution sequence of GMCs.

Relationships among cloud occurrence frequency, overlap, and effective thickness derived from CALIPSO and CloudSat merged cloud vertical profiles

Science.gov (United States)

Kato, Seiji; Sun-Mack, Sunny; Miller, Walter F.; Rose, Fred G.; Chen, Yan; Minnis, Patrick; Wielicki, Bruce A.

2010-01-01

A cloud frequency of occurrence matrix is generated using merged cloud vertical profiles derived from the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and cloud profiling radar. The matrix contains vertical profiles of cloud occurrence frequency as a function of the uppermost cloud top. It is shown that the cloud fraction and uppermost cloud top vertical profiles can be related by a cloud overlap matrix when the correlation length of cloud occurrence, which is interpreted as an effective cloud thickness, is introduced. The underlying assumption in establishing the above relation is that cloud overlap approaches random overlap with increasing distance separating cloud layers and that the probability of deviating from random overlap decreases exponentially with distance. One month of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat data (July 2006) support these assumptions, although the correlation length sometimes increases with separation distance when the cloud top height is large. The data also show that the correlation length depends on cloud top hight and the maximum occurs when the cloud top height is 8 to 10 km. The cloud correlation length is equivalent to the decorrelation distance introduced by Hogan and Illingworth (2000) when cloud fractions of both layers in a two-cloud layer system are the same. The simple relationships derived in this study can be used to estimate the top-of-atmosphere irradiance difference caused by cloud fraction, uppermost cloud top, and cloud thickness vertical profile differences.

Research on cloud-based remote measurement and analysis system

Science.gov (United States)

Gao, Zhiqiang; He, Lingsong; Su, Wei; Wang, Can; Zhang, Changfan

2015-02-01

The promising potential of cloud computing and its convergence with technologies such as cloud storage, cloud push, mobile computing allows for creation and delivery of newer type of cloud service. Combined with the thought of cloud computing, this paper presents a cloud-based remote measurement and analysis system. This system mainly consists of three parts: signal acquisition client, web server deployed on the cloud service, and remote client. This system is a special website developed using asp.net and Flex RIA technology, which solves the selective contradiction between two monitoring modes, B/S and C/S. This platform supplies customer condition monitoring and data analysis service by Internet, which was deployed on the cloud server. Signal acquisition device is responsible for data (sensor data, audio, video, etc.) collection and pushes the monitoring data to the cloud storage database regularly. Data acquisition equipment in this system is only conditioned with the function of data collection and network function such as smartphone and smart sensor. This system's scale can adjust dynamically according to the amount of applications and users, so it won't cause waste of resources. As a representative case study, we developed a prototype system based on Ali cloud service using the rotor test rig as the research object. Experimental results demonstrate that the proposed system architecture is feasible.

Analysis and Verification of a Key Agreement Protocol over Cloud Computing Using Scyther Tool

OpenAIRE

Hazem A Elbaz

2015-01-01

The mostly cloud computing authentication mechanisms use public key infrastructure (PKI). Hierarchical Identity Based Cryptography (HIBC) has several advantages that sound well align with the demands of cloud computing. The main objectives of cloud computing authentication protocols are security and efficiency. In this paper, we clarify Hierarchical Identity Based Authentication Key Agreement (HIB-AKA) protocol, providing lightweight key management approach for cloud computing users. Then, we...

Making and Breaking Clouds

Science.gov (United States)

Kohler, Susanna

2017-10-01

they create. But to match with observations, this wouldsuggest that molecular clouds are short-lived objects that are built (and therefore replenished) just as quickly as they are destroyed. Is this possible?Speedy Building?In a recent study, a team of scientists led by Mordecai-Mark Mac Low (American Museum of Natural History and Heidelberg University, Germany) explore whether there is a way to create molecular clouds rapidly enough to match the necessary rate of destruction.Mac Low and collaborators find that some common mechanisms used to explain the formation of molecular clouds like gas being swept up by supernovae cant quite operate quickly enough to combat the rate of cloud destruction. On the other hand, the Toomre gravitational instability,which is a large-scale gravitational instability that occurs in gas disks,can very rapidly assemble gas into clumps dense enough to form molecules.A composite of visible and near-infrared images from the VLT ANTU telescope of the Barnard 68 molecular cloud, roughly half a light-year in diameter. [ESO]A Rapid CycleBased on their findings, the authors argue that dense, star-forming molecular clouds persist only for a short time before collapsing into stars and then being blown apart by stellar feedback but these very clouds are built equally quickly via gravitational instabilities.Conveniently, this model has a very testable prediction: the Toomre instability is expected to become even stronger at higher redshift, which suggests that the fraction of gas in the form of molecules should increase at high redshifts. This appears to agree with observations, supporting the authors picture of a rapid cycle of cloud assembly and destruction.CitationMordecai-Mark Mac Low et al 2017 ApJL 847 L10. doi:10.3847/2041-8213/aa8a61

Clustering, randomness, and regularity in cloud fields: 2. Cumulus cloud fields

Science.gov (United States)

Zhu, T.; Lee, J.; Weger, R. C.; Welch, R. M.

1992-12-01

During the last decade a major controversy has been brewing concerning the proper characterization of cumulus convection. The prevailing view has been that cumulus clouds form in clusters, in which cloud spacing is closer than that found for the overall cloud field and which maintains its identity over many cloud lifetimes. This "mutual protection hypothesis" of Randall and Huffman (1980) has been challenged by the "inhibition hypothesis" of Ramirez et al. (1990) which strongly suggests that the spatial distribution of cumuli must tend toward a regular distribution. A dilemma has resulted because observations have been reported to support both hypotheses. The present work reports a detailed analysis of cumulus cloud field spatial distributions based upon Landsat, Advanced Very High Resolution Radiometer, and Skylab data. Both nearest-neighbor and point-to-cloud cumulative distribution function statistics are investigated. The results show unequivocally that when both large and small clouds are included in the cloud field distribution, the cloud field always has a strong clustering signal. The strength of clustering is largest at cloud diameters of about 200-300 m, diminishing with increasing cloud diameter. In many cases, clusters of small clouds are found which are not closely associated with large clouds. As the small clouds are eliminated from consideration, the cloud field typically tends towards regularity. Thus it would appear that the "inhibition hypothesis" of Ramirez and Bras (1990) has been verified for the large clouds. However, these results are based upon the analysis of point processes. A more exact analysis also is made which takes into account the cloud size distributions. Since distinct clouds are by definition nonoverlapping, cloud size effects place a restriction upon the possible locations of clouds in the cloud field. The net effect of this analysis is that the large clouds appear to be randomly distributed, with only weak tendencies towards

ICES IN THE QUIESCENT IC 5146 DENSE CLOUD

International Nuclear Information System (INIS)

Chiar, J. E.; Pendleton, Y. J.; Allamandola, L. J.; Ennico, K.; Greene, T. P.; Roellig, T. L.; Sandford, S. A.; Boogert, A. C. A.; Geballe, T. R.; Mason, R. E.; Keane, J. V.; Lada, C. J.; Tielens, A. G. G. M.; Werner, M. W.; Whittet, D. C. B.; Decin, L.; Eriksson, K.

2011-01-01

This paper presents spectra in the 2 to 20 μm range of quiescent cloud material located in the IC 5146 cloud complex. The spectra were obtained with NASA's Infrared Telescope Facility SpeX instrument and the Spitzer Space Telescope's Infrared Spectrometer. We use these spectra to investigate dust and ice absorption features in pristine regions of the cloud that are unaltered by embedded stars. We find that the H 2 O-ice threshold extinction is 4.03 ± 0.05 mag. Once foreground extinction is taken into account, however, the threshold drops to 3.2 mag, equivalent to that found for the Taurus dark cloud, generally assumed to be the touchstone quiescent cloud against which all other dense cloud and embedded young stellar object observations are compared. Substructure in the trough of the silicate band for two sources is attributed to CH 3 OH and NH 3 in the ices, present at the ∼2% and ∼5% levels, respectively, relative to H 2 O-ice. The correlation of the silicate feature with the E(J - K) color excess is found to follow a much shallower slope relative to lines of sight that probe diffuse clouds, supporting the previous results by Chiar et al.

Featured Image: A Molecular Cloud Outside Our Galaxy

Science.gov (United States)

Kohler, Susanna

2018-06-01

What do molecular clouds look like outside of our own galaxy? See for yourself in the images above and below of N55, a molecular cloud located in the Large Magellanic Cloud (LMC). In a recent study led by Naslim Neelamkodan (Academia Sinica Institute of Astronomy and Astrophysics, Taiwan), a team of scientists explore N55 to determine how its cloud properties differ from clouds within the Milky Way. The image above reveals the distribution of infrared-emitting gas and dust observed in three bands by the Spitzer Space Telescope. Overplotted in cyan are observations from the Atacama Submillimeter Telescope Experiment tracing the clumpy, warm molecular gas. Below, new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the sub-parsec-scale molecular clumps in greater detail, showing the correlation of massive clumps with Spitzer-identified young stellar objects (crosses). The study presented here indicates that this cloud in the LMC is the site of massive star formation, with properties similar to equivalent clouds in the Milky Way. To learn more about the authors findings, check out the article linked below.CitationNaslim N. et al 2018 ApJ 853 175. doi:10.3847/1538-4357/aaa5b0

Inverse modeling of cloud-aerosol interactions -- Part 1: Detailed response surface analysis

NARCIS (Netherlands)

Partridge, D.G.; Vrugt, J.A.; Tunved, P.; Ekman, A.M.L.; Gorea, D.; Sooroshian, A.

2011-01-01

New methodologies are required to probe the sensitivity of parameters describing cloud droplet activation. This paper presents an inverse modeling-based method for exploring cloud-aerosol interactions via response surfaces. The objective function, containing the difference between the measured and

Making the most of cloud storage - a toolkit for exploitation by WLCG experiments

Science.gov (United States)

Alvarez Ayllon, Alejandro; Arsuaga Rios, Maria; Bitzes, Georgios; Furano, Fabrizio; Keeble, Oliver; Manzi, Andrea

2017-10-01

Understanding how cloud storage can be effectively used, either standalone or in support of its associated compute, is now an important consideration for WLCG. We report on a suite of extensions to familiar tools targeted at enabling the integration of cloud object stores into traditional grid infrastructures and workflows. Notable updates include support for a number of object store flavours in FTS3, Davix and gfal2, including mitigations for lack of vector reads; the extension of Dynafed to operate as a bridge between grid and cloud domains; protocol translation in FTS3; the implementation of extensions to DPM (also implemented by the dCache project) to allow 3rd party transfers over HTTP. The result is a toolkit which facilitates data movement and access between grid and cloud infrastructures, broadening the range of workflows suitable for cloud. We report on deployment scenarios and prototype experience, explaining how, for example, an Amazon S3 or Azure allocation can be exploited by grid workflows.

Use of the ARM Measurements of Spectral Zenith Radiance for Better Understanding of 3D Cloud-Radiation Processes & Aerosol-Cloud Interaction

Energy Technology Data Exchange (ETDEWEB)

Alexander Marshak; Warren Wiscombe; Yuri Knyazikhin; Christine Chiu

2011-05-24

We proposed a variety of tasks centered on the following question: what can we learn about 3D cloud-radiation processes and aerosol-cloud interaction from rapid-sampling ARM measurements of spectral zenith radiance? These ARM measurements offer spectacular new and largely unexploited capabilities in both the temporal and spectral domains. Unlike most other ARM instruments, which average over many seconds or take samples many seconds apart, the new spectral zenith radiance measurements are fast enough to resolve natural time scales of cloud change and cloud boundaries as well as the transition zone between cloudy and clear areas. In the case of the shortwave spectrometer, the measurements offer high time resolution and high spectral resolution, allowing new discovery-oriented science which we intend to pursue vigorously. Research objectives are, for convenience, grouped under three themes: • Understand radiative signature of the transition zone between cloud-free and cloudy areas using data from ARM shortwave radiometers, which has major climatic consequences in both aerosol direct and indirect effect studies. • Provide cloud property retrievals from the ARM sites and the ARM Mobile Facility for studies of aerosol-cloud interactions. • Assess impact of 3D cloud structures on aerosol properties using passive and active remote sensing techniques from both ARM and satellite measurements.

A Spectroscopic Study of Young Stellar Objects in the Serpens Cloud Core and NGC 1333

Science.gov (United States)

Winston, E.; Megeath, S. T.; Wolk, S. J.; Hernandez, J.; Gutermuth, R.; Muzerolle, J.; Hora, J. L.; Covey, K.; Allen, L. E.; Spitzbart, B.; Peterson, D.; Myers, P.; Fazio, G. G.

2009-06-01

We present spectral observations of 130 young stellar objects (YSOs) in the Serpens Cloud Core and NGC 1333 embedded clusters. The observations consist of near-IR spectra in the H and K bands from SpeX on the IRTF and far-red spectra (6000-9000 Å) from Hectospec on the Multi-Mirror Telescope. These YSOs were identified in previous Spitzer and Chandra observations, and the evolutionary classes of the YSOs were determined from the Spitzer mid-IR photometry. With these spectra we search for corroborating evidence for the pre-main-sequence nature of the objects, study the properties of the detected emission lines as a function of evolutionary class, and obtain spectral types for the observed YSOs. The temperatures implied by the spectral types are combined with luminosities determined from the near-IR photometry to construct Hertzsprung-Russell (H-R) diagrams for the clusters. By comparing the positions of the YSOs in the H-R diagrams with the pre-main-sequence tracks of Baraffe (1998), we determine the ages of the embedded sources and study the relative ages of the YSOs with and without optically thick circumstellar disks. The apparent isochronal ages of the YSOs in both clusters range from less than 1 Myr to 10 Myr, with most objects below 3 Myr. The observed distributions of ages for the Class II and Class III objects are statistically indistinguishable. We examine the spatial distribution and extinction of the YSOs as a function of their isochronal ages. We find the sources dispersed and are not deeply embedded. Nonetheless, the sources with isochronal ages >3 Myr show all the characteristics of YSOs in their spectra, their IR spectral energy distributions, and their X-ray emission; we find no evidence that they are contaminating background giants or foreground dwarfs. However, we find no corresponding decrease in the fraction of sources with infrared excess with isochronal age; this suggests that the older isochronal ages may not measure the true age of the >3

CLOUD EDUCATIONAL RESOURCES FOR PHYSICS LEARNING RESEARCHES SUPPORT

Directory of Open Access Journals (Sweden)

Oleksandr V. Merzlykin

2015-10-01

Full Text Available The definition of cloud educational resource is given in paper. Its program and information components are characterized. The virtualization as the technological ground of transforming from traditional electronic educational resources to cloud ones is reviewed. Such levels of virtualization are described: data storage device virtualization (Data as Service, hardware virtualization (Hardware as Service, computer virtualization (Infrastructure as Service, software system virtualization (Platform as Service, «desktop» virtualization (Desktop as Service, software user interface virtualization (Software as Service. Possibilities of designing the cloud educational resources system for physics learning researches support taking into account standards of learning objects metadata (accessing via OAI-PMH protocol and standards of learning tools interoperability (LTI are shown. The example of integration cloud educational resources into Moodle learning management system with use of OAI-PMH and LTI is given.

Laboratory Studies of Ethane Ice Relevant to Outer Solar System Surfaces

Science.gov (United States)

Moore, Marla H.; Hudson, Reggie; Raines, Lily

2009-01-01

Oort Cloud comets, as well as TNOs Makemake (2045 FYg), Quaoar, and Pluto, are known to contain ethane. However, even though this molecule is found on several outer Solar System objects relatively little information is available about its amorphous and crystalline phases. In new experiments, we have prepared ethane ices at temperatures applicable to the outer Solar System, and have heated and ion-irradiated these ices to study phase changes and ethane's radiation chemistry using mid-IR spectroscopy (2.2 - 16.6 microns). Included in our work is the meta-stable phase that exists at 35 - 55 K. These results, including newly obtained optical constants, are relevant to ground-based observational campaigns, the New Horizons mission, and supporting laboratory work. An improved understanding of solid-phase ethane may contribute to future searches for this and other hydrocarbons in the outer Solar System.

Hierarchical extraction of urban objects from mobile laser scanning data

Science.gov (United States)

Yang, Bisheng; Dong, Zhen; Zhao, Gang; Dai, Wenxia

2015-01-01

Point clouds collected in urban scenes contain a huge number of points (e.g., billions), numerous objects with significant size variability, complex and incomplete structures, and variable point densities, raising great challenges for the automated extraction of urban objects in the field of photogrammetry, computer vision, and robotics. This paper addresses these challenges by proposing an automated method to extract urban objects robustly and efficiently. The proposed method generates multi-scale supervoxels from 3D point clouds using the point attributes (e.g., colors, intensities) and spatial distances between points, and then segments the supervoxels rather than individual points by combining graph based segmentation with multiple cues (e.g., principal direction, colors) of the supervoxels. The proposed method defines a set of rules for merging segments into meaningful units according to types of urban objects and forms the semantic knowledge of urban objects for the classification of objects. Finally, the proposed method extracts and classifies urban objects in a hierarchical order ranked by the saliency of the segments. Experiments show that the proposed method is efficient and robust for extracting buildings, streetlamps, trees, telegraph poles, traffic signs, cars, and enclosures from mobile laser scanning (MLS) point clouds, with an overall accuracy of 92.3%.

Mobile web browsing using the cloud

CERN Document Server

Zhao, Bo; Cao, Guohong

2013-01-01

This brief surveys existing techniques to address the problem of long delays and high power consumption for web browsing on smartphones, which can be due to the local computational limitation at the smartphone (e.g., running java scripts or flash objects) level. To address this issue, an architecture called Virtual-Machine based Proxy (VMP) is introduced, shifting the computing from smartphones to the VMP which may reside in the cloud. Mobile Web Browsing Using the Cloud illustrates the feasibility of deploying the proposed VMP system in 3G networks through a prototype using Xen virtual machin

Cloud occurrences and cloud radiative effects (CREs) from CERES-CALIPSO-CloudSat-MODIS (CCCM) and CloudSat radar-lidar (RL) products

Science.gov (United States)

Ham, Seung-Hee; Kato, Seiji; Rose, Fred G.; Winker, David; L'Ecuyer, Tristan; Mace, Gerald G.; Painemal, David; Sun-Mack, Sunny; Chen, Yan; Miller, Walter F.

2017-08-01

Two kinds of cloud products obtained from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), CloudSat, and Moderate Resolution Imaging Spectroradiometer (MODIS) are compared and analyzed in this study: Clouds and the Earth's Radiant Energy System (CERES)-CALIPSO-CloudSat-MODIS (CCCM) product and CloudSat radar-lidar products such as GEOPROF-LIDAR and FLXHR-LIDAR. Compared to GEOPROF-LIDAR, low-level (40°). The difference occurs when hydrometeors are detected by CALIPSO lidar but are undetected by CloudSat radar. In the comparison of cloud radiative effects (CREs), global mean differences between CCCM and FLXHR-LIDAR are mostly smaller than 5 W m-2, while noticeable regional differences are found. For example, CCCM shortwave (SW) and longwave (LW) CREs are larger than FXLHR-LIDAR along the west coasts of Africa and America because the GEOPROF-LIDAR algorithm misses shallow marine boundary layer clouds. In addition, FLXHR-LIDAR SW CREs are larger than the CCCM counterpart over tropical oceans away from the west coasts of America. Over midlatitude storm-track regions, CCCM SW and LW CREs are larger than the FLXHR-LIDAR counterpart.

Challenges for Cloud Modeling in the Context of Aerosol–Cloud–Precipitation Interactions

Energy Technology Data Exchange (ETDEWEB)

Lebo, Zachary J. [Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming; Shipway, Ben J. [Met Office, Exeter, United Kingdom; Fan, Jiwen [Pacific Northwest National Laboratory, Richland, Washington; Geresdi, Istvan [Faculty of Science, University of Pécs, Pécs, Hungary; Hill, Adrian [Met Office, Exeter, United Kingdom; Miltenberger, Annette [School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Morrison, Hugh [Mesoscale and Microscale Meteorology Laboratory, National Center for Atmospheric Research, Boulder, Colorado; Rosenberg, Phil [School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Varble, Adam [Department of Atmospheric Sciences, University of Utah, Salt Lake City, Utah; Xue, Lulin [Research Applications Laboratory, National Center for Atmospheric Research, Boulder, Colorado

2017-08-01

The International Cloud Modeling Workshop (CMW) has been a longstanding tradition in the cloud microphysics modeling community and is typically held the week prior to the International Conference on Clouds and Precipitation (ICCP). For the Ninth CMW, more than 40 participants from 10 countries convened at the Met Office in Exeter, United Kingdom. The workshop included 4 detailed case studies (described in more detail below) rooted in recent field campaigns. The overarching objective of these cases was to utilize new observations to better understand inter-model differences and model deficiencies, explore new modeling techniques, and gain physical insight into the behavior of clouds. As was the case at the Eighth CMW, there was a general theme of understanding the role of aerosol impacts in the context of cloud-precipitation interactions. However, an additional objective was the focal point of several cases at the most recent workshop: microphysical-dynamical interactions. Many of the cases focused less on idealized small-domain simulations (as was the general focus of previous workshops) and more on large-scale nested configurations examining effects at various scales.

Towards 4d Virtual City Reconstruction from LIDAR Point Cloud Sequences

Science.gov (United States)

Józsa, O.; Börcs, A.; Benedek, C.

2013-05-01

In this paper we propose a joint approach on virtual city reconstruction and dynamic scene analysis based on point cloud sequences of a single car-mounted Rotating Multi-Beam (RMB) Lidar sensor. The aim of the addressed work is to create 4D spatio-temporal models of large dynamic urban scenes containing various moving and static objects. Standalone RMB Lidar devices have been frequently applied in robot navigation tasks and proved to be efficient in moving object detection and recognition. However, they have not been widely exploited yet for geometric approximation of ground surfaces and building facades due to the sparseness and inhomogeneous density of the individual point cloud scans. In our approach we propose an automatic registration method of the consecutive scans without any additional sensor information such as IMU, and introduce a process for simultaneously extracting reconstructed surfaces, motion information and objects from the registered dense point cloud completed with point time stamp information.

Relation of Cloud Occurrence Frequency, Overlap, and Effective Thickness Derived from CALIPSO and CloudSat Merged Cloud Vertical Profiles

Science.gov (United States)

Kato, Seiji; Sun-Mack, Sunny; Miller, Walter F.; Rose, Fred G.; Chen, Yan; Minnis, Patrick; Wielicki, Bruce A.

2009-01-01

A cloud frequency of occurrence matrix is generated using merged cloud vertical profile derived from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR). The matrix contains vertical profiles of cloud occurrence frequency as a function of the uppermost cloud top. It is shown that the cloud fraction and uppermost cloud top vertical pro les can be related by a set of equations when the correlation distance of cloud occurrence, which is interpreted as an effective cloud thickness, is introduced. The underlying assumption in establishing the above relation is that cloud overlap approaches the random overlap with increasing distance separating cloud layers and that the probability of deviating from the random overlap decreases exponentially with distance. One month of CALIPSO and CloudSat data support these assumptions. However, the correlation distance sometimes becomes large, which might be an indication of precipitation. The cloud correlation distance is equivalent to the de-correlation distance introduced by Hogan and Illingworth [2000] when cloud fractions of both layers in a two-cloud layer system are the same.

Intuitive modeling of vaporish objects

International Nuclear Information System (INIS)

Sokolov, Dmitry; Gentil, Christian

2015-01-01

Attempts to model gases in computer graphics started in the late 1970s. Since that time, there have been many approaches developed. In this paper we present a non-physical method allowing to create vaporish objects like clouds or smoky characters. The idea is to create a few sketches describing the rough shape of the final vaporish object. These sketches will be used as condensation sets of Iterated Function Systems, providing intuitive control over the object. The advantages of the new method are: simplicity, good control of resulting shapes and ease of eventual object animation.

Influence of Meteorological Regimes on Cloud Microphysics Over Ross Island, Antarctica

Science.gov (United States)

Glennon, C.; Wang, S. H.; Scott, R. C.; Bromwich, D. H.; Lubin, D.

2017-12-01

The Antarctic provides a sharp contrast in cloud microphysics from the high Arctic, due to orographic lifting and resulting strong vertical motions induced by mountain ranges and other varying terrain on several spatial scales. The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment (AWARE) deployed advanced cloud remote sensing equipment to Ross Island, Antarctica, from December 2015 until January 2016. This equipment included scanning and zenith radars operating in the Ka and X bands, a high spectral resolution lidar (HSRL), and a polarized micropulse lidar (MPL). A major AWARE objective is to provide state-of-the-art data for improving cloud microphysical parameterizations in climate models. To further this objective we have organized and classified the local Ross Island meteorology into distinct regimes using k-means clustering on ERA-Interim reanalysis data. We identify synoptic categories producing unique regimes of cloud cover and cloud microphysical properties over Ross Island. Each day of observations can then be associated with a specific meteorological regime, thus assisting modelers with identifying case studies. High-resolution (1 km) weather forecasts from the Antarctic Mesoscale Prediction System (AMPS) are sorted into these categories. AMPS-simulated anomalies of cloud fraction, near-surface air temperature, and vertical velocity at 500-mb are composited and compared with ground-based radar and lidar-derived cloud properties to identify mesoscale meteorological processes driving Antarctic cloud formation. Synoptic lows over the Ross and Amundsen Seas drive anomalously warm conditions at Ross Island by injecting marine air masses inland over the West Antarctic Ice Sheet (WAIS). This results in ice and mixed-phase orographic cloud systems arriving at Ross Island from the south to southeast along the Transantarctic Mountains. In contrast, blocking over the Amundsen Sea region brings classical liquid-dominated mixed-phase and

Contrasting Cloud Composition Between Coupled and Decoupled Marine Boundary Layer Clouds

Science.gov (United States)

WANG, Z.; Mora, M.; Dadashazar, H.; MacDonald, A.; Crosbie, E.; Bates, K. H.; Coggon, M. M.; Craven, J. S.; Xian, P.; Campbell, J. R.; AzadiAghdam, M.; Woods, R. K.; Jonsson, H.; Flagan, R. C.; Seinfeld, J.; Sorooshian, A.

2016-12-01

Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the ocean surface. This study contrasts cloud chemical composition between coupled and decoupled marine stratocumulus clouds. Cloud water and droplet residual particle composition were measured in clouds off the California coast during three airborne experiments in July-August of separate years (E-PEACE 2011, NiCE 2013, BOAS 2015). Decoupled clouds exhibited significantly lower overall mass concentrations in both cloud water and droplet residual particles, consistent with reduced cloud droplet number concentration and sub-cloud aerosol (Dp > 100 nm) number concentration, owing to detachment from surface sources. Non-refractory sub-micrometer aerosol measurements show that coupled clouds exhibit higher sulfate mass fractions in droplet residual particles, owing to more abundant precursor emissions from the ocean and ships. Consequently, decoupled clouds exhibited higher mass fractions of organics, nitrate, and ammonium in droplet residual particles, owing to effects of long-range transport from more distant sources. Total cloud water mass concentration in coupled clouds was dominated by sodium and chloride, and their mass fractions and concentrations exceeded those in decoupled clouds. Conversely, with the exception of sea salt constituents (e.g., Cl, Na, Mg, K), cloud water mass fractions of all species examined were higher in decoupled clouds relative to coupled clouds. These results suggest that an important variable is the extent to which clouds are coupled to the surface layer when interpreting microphysical data relevant to clouds and aerosol particles.

Large-scale urban point cloud labeling and reconstruction

Science.gov (United States)

Zhang, Liqiang; Li, Zhuqiang; Li, Anjian; Liu, Fangyu

2018-04-01

The large number of object categories and many overlapping or closely neighboring objects in large-scale urban scenes pose great challenges in point cloud classification. In this paper, a novel framework is proposed for classification and reconstruction of airborne laser scanning point cloud data. To label point clouds, we present a rectified linear units neural network named ReLu-NN where the rectified linear units (ReLu) instead of the traditional sigmoid are taken as the activation function in order to speed up the convergence. Since the features of the point cloud are sparse, we reduce the number of neurons by the dropout to avoid over-fitting of the training process. The set of feature descriptors for each 3D point is encoded through self-taught learning, and forms a discriminative feature representation which is taken as the input of the ReLu-NN. The segmented building points are consolidated through an edge-aware point set resampling algorithm, and then they are reconstructed into 3D lightweight models using the 2.5D contouring method (Zhou and Neumann, 2010). Compared with deep learning approaches, the ReLu-NN introduced can easily classify unorganized point clouds without rasterizing the data, and it does not need a large number of training samples. Most of the parameters in the network are learned, and thus the intensive parameter tuning cost is significantly reduced. Experimental results on various datasets demonstrate that the proposed framework achieves better performance than other related algorithms in terms of classification accuracy and reconstruction quality.

Deep convective clouds at the tropopause

Directory of Open Access Journals (Sweden)

H. H. Aumann

2011-02-01

Full Text Available Data from the Atmospheric Infrared Sounder (AIRS on the EOS Aqua spacecraft each day show tens of thousands of Cold Clouds (CC in the tropical oceans with 10 μm window channel brightness temperatures colder than 225 K. These clouds represent a mix of cold anvil clouds and Deep Convective Clouds (DCC. This mix can be separated by computing the difference between two channels, a window channel and a channel with strong CO₂ absorption: for some cold clouds this difference is negative, i.e. the spectra for some cold clouds are inverted. We refer to cold clouds with spectra which are more than 2 K inverted as DCCi2. Associated with DCCi2 is a very high rain rate and a local upward displacement of the tropopause, a cold "bulge", which can be seen directly in the brightness temperatures of AIRS and Advanced Microwave Sounding Unit (AMSU temperature sounding channels in the lower stratosphere. The very high rain rate and the local distortion of the tropopause indicate that DCCi2 objects are associated with severe storms. Significant long-term trends in the statistical properties of DCCi2 could be interesting indicators of climate change. While the analysis of the nature and physical conditions related to DCCi2 requires hyperspectral infrared and microwave data, the identification of DCCi2 requires only one good window channel and one strong CO₂ sounding channel. This suggests that improved identification of severe storms with future advanced geostationary satellites could be accomplished with the addition of one or two narrow band channels.

OpenID Connect as a security service in cloud-based medical imaging systems.

Science.gov (United States)

Ma, Weina; Sartipi, Kamran; Sharghigoorabi, Hassan; Koff, David; Bak, Peter

2016-04-01

The evolution of cloud computing is driving the next generation of medical imaging systems. However, privacy and security concerns have been consistently regarded as the major obstacles for adoption of cloud computing by healthcare domains. OpenID Connect, combining OpenID and OAuth together, is an emerging representational state transfer-based federated identity solution. It is one of the most adopted open standards to potentially become the de facto standard for securing cloud computing and mobile applications, which is also regarded as "Kerberos of cloud." We introduce OpenID Connect as an authentication and authorization service in cloud-based diagnostic imaging (DI) systems, and propose enhancements that allow for incorporating this technology within distributed enterprise environments. The objective of this study is to offer solutions for secure sharing of medical images among diagnostic imaging repository (DI-r) and heterogeneous picture archiving and communication systems (PACS) as well as Web-based and mobile clients in the cloud ecosystem. The main objective is to use OpenID Connect open-source single sign-on and authorization service and in a user-centric manner, while deploying DI-r and PACS to private or community clouds should provide equivalent security levels to traditional computing model.

A scoping review of cloud computing in healthcare

OpenAIRE

Griebel, Lena; Prokosch, Hans-Ulrich; Köpcke, Felix; Toddenroth, Dennis; Christoph, Jan; Leb, Ines; Engel, Igor; Sedlmayr, Martin

2015-01-01

Background Cloud computing is a recent and fast growing area of development in healthcare. Ubiquitous, on-demand access to virtually endless resources in combination with a pay-per-use model allow for new ways of developing, delivering and using services. Cloud computing is often used in an ?OMICS-context?, e.g. for computing in genomics, proteomics and molecular medicine, while other field of application still seem to be underrepresented. Thus, the objective of this scoping review was to ide...

Fast cloud parameter retrievals of MIPAS/Envisat

Directory of Open Access Journals (Sweden)

R. Spang

2012-08-01

Full Text Available The infrared limb spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS on board the Envisat satellite include detailed information on tropospheric clouds and polar stratospheric clouds (PSC. However, no consolidated cloud product is available for the scientific community. Here we describe a fast prototype processor for cloud parameter retrieval from MIPAS (MIPclouds. Retrieval of parameters such as cloud top height, temperature, and extinction are implemented, as well as retrieval of microphysical parameters, e.g. effective radius and the integrated quantities over the limb path (surface area density and volume density. MIPclouds classifies clouds as either liquid or ice cloud in the upper troposphere and polar stratospheric clouds types in the stratosphere based on statistical combinations of colour ratios and brightness temperature differences.

Comparison of limb measurements of clouds with model results or cloud parameters from nadir looking instruments is often difficult due to different observation geometries. We therefore introduce a new concept, the limb-integrated surface area density path (ADP. By means of validation and radiative transfer calculations of realistic 2-D cloud fields as input for a blind test retrieval (BTR, we demonstrate that ADP is an extremely valuable parameter for future comparison with model data of ice water content, when applying limb integration (ray tracing through the model fields. In addition, ADP is used for a more objective definition of detection thresholds of the applied detection methods. Based on BTR, a detection threshold of ADP = 10⁷ μm² cm⁻² and an ice water content of 10⁻⁵ g m⁻³ is estimated, depending on the horizontal and vertical extent of the cloud.

Intensive validation of the cloud detection methods shows that the limb-sounding MIPAS instrument has a sensitivity in detecting stratospheric

Context-aware distributed cloud computing using CloudScheduler

Science.gov (United States)

Seuster, R.; Leavett-Brown, CR; Casteels, K.; Driemel, C.; Paterson, M.; Ring, D.; Sobie, RJ; Taylor, RP; Weldon, J.

2017-10-01

The distributed cloud using the CloudScheduler VM provisioning service is one of the longest running systems for HEP workloads. It has run millions of jobs for ATLAS and Belle II over the past few years using private and commercial clouds around the world. Our goal is to scale the distributed cloud to the 10,000-core level, with the ability to run any type of application (low I/O, high I/O and high memory) on any cloud. To achieve this goal, we have been implementing changes that utilize context-aware computing designs that are currently employed in the mobile communication industry. Context-awareness makes use of real-time and archived data to respond to user or system requirements. In our distributed cloud, we have many opportunistic clouds with no local HEP services, software or storage repositories. A context-aware design significantly improves the reliability and performance of our system by locating the nearest location of the required services. We describe how we are collecting and managing contextual information from our workload management systems, the clouds, the virtual machines and our services. This information is used not only to monitor the system but also to carry out automated corrective actions. We are incrementally adding new alerting and response services to our distributed cloud. This will enable us to scale the number of clouds and virtual machines. Further, a context-aware design will enable us to run analysis or high I/O application on opportunistic clouds. We envisage an open-source HTTP data federation (for example, the DynaFed system at CERN) as a service that would provide us access to existing storage elements used by the HEP experiments.

AceCloud: Molecular Dynamics Simulations in the Cloud.

Science.gov (United States)

Harvey, M J; De Fabritiis, G

2015-05-26

We present AceCloud, an on-demand service for molecular dynamics simulations. AceCloud is designed to facilitate the secure execution of large ensembles of simulations on an external cloud computing service (currently Amazon Web Services). The AceCloud client, integrated into the ACEMD molecular dynamics package, provides an easy-to-use interface that abstracts all aspects of interaction with the cloud services. This gives the user the experience that all simulations are running on their local machine, minimizing the learning curve typically associated with the transition to using high performance computing services.

VMware private cloud computing with vCloud director

CERN Document Server

Gallagher, Simon

2013-01-01

It's All About Delivering Service with vCloud Director Empowered by virtualization, companies are not just moving into the cloud, they're moving into private clouds for greater security, flexibility, and cost savings. However, this move involves more than just infrastructure. It also represents a different business model and a new way to provide services. In this detailed book, VMware vExpert Simon Gallagher makes sense of private cloud computing for IT administrators. From basic cloud theory and strategies for adoption to practical implementation, he covers all the issues. You'll lea

On the influence of cloud fraction diurnal cycle and sub-grid cloud optical thickness variability on all-sky direct aerosol radiative forcing

International Nuclear Information System (INIS)

Min, Min; Zhang, Zhibo

2014-01-01

The objective of this study is to understand how cloud fraction diurnal cycle and sub-grid cloud optical thickness variability influence the all-sky direct aerosol radiative forcing (DARF). We focus on the southeast Atlantic region where transported smoke is often observed above low-level water clouds during burning seasons. We use the CALIOP observations to derive the optical properties of aerosols. We developed two diurnal cloud fraction variation models. One is based on sinusoidal fitting of MODIS observations from Terra and Aqua satellites. The other is based on high-temporal frequency diurnal cloud fraction observations from SEVIRI on board of geostationary satellite. Both models indicate a strong cloud fraction diurnal cycle over the southeast Atlantic region. Sensitivity studies indicate that using a constant cloud fraction corresponding to Aqua local equatorial crossing time (1:30 PM) generally leads to an underestimated (less positive) diurnal mean DARF even if solar diurnal variation is considered. Using cloud fraction corresponding to Terra local equatorial crossing time (10:30 AM) generally leads overestimation. The biases are a typically around 10–20%, but up to more than 50%. The influence of sub-grid cloud optical thickness variability on DARF is studied utilizing the cloud optical thickness histogram available in MODIS Level-3 daily data. Similar to previous studies, we found the above-cloud smoke in the southeast Atlantic region has a strong warming effect at the top of the atmosphere. However, because of the plane-parallel albedo bias the warming effect of above-cloud smoke could be significantly overestimated if the grid-mean, instead of the full histogram, of cloud optical thickness is used in the computation. This bias generally increases with increasing above-cloud aerosol optical thickness and sub-grid cloud optical thickness inhomogeneity. Our results suggest that the cloud diurnal cycle and sub-grid cloud variability are important factors

EVIDENCE FOR CLOUD-CLOUD COLLISION AND PARSEC-SCALE STELLAR FEEDBACK WITHIN THE L1641-N REGION

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Fumitaka [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Miura, Tomoya; Nishi, Ryoichi [Department of Physics, Niigata University, 8050 Ikarashi-2, Niigata 950-2181 (Japan); Kitamura, Yoshimi; Akashi, Toshiya; Ikeda, Norio [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Shimajiri, Yoshito; Kawabe, Ryohei [Nobeyama Radio Observatory, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Tsukagoshi, Takashi [Department of Astronomy, School of Science, University of Tokyo, Bunkyo, Tokyo 113-0033 (Japan); Momose, Munetake [Institute of Astrophysics and Planetary Sciences, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Li Zhiyun, E-mail: fumitaka.nakamura@nao.ac.jp [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)

2012-02-10

We present high spatial resolution {sup 12}CO (J = 1-0) images taken by the Nobeyama 45 m telescope toward a 48' Multiplication-Sign 48' area, including the L1641-N cluster. The effective spatial resolution of the maps is 21'', corresponding to 0.04 pc at a distance of 400 pc. A recent 1.1 mm dust continuum map reveals that the dense gas is concentrated in several thin filaments. We find that a few dust filaments are located at the parts where {sup 12}CO (J = 1-0) emission drops sharply. Furthermore, the filaments have two components with different velocities. The velocity difference between the two components is about 3 km s{sup -1}, corresponding to a Mach number of 10, significantly larger than the local turbulent velocity in the cloud. These facts imply that the collision of the two components (hereafter, the cloud-cloud collision) possibly contributed to the formation of these filaments. Since the two components appear to overlap toward the filaments on the plane of the sky, the collision may have occurred almost along the line of sight. Star formation in the L1641-N cluster was probably triggered by such a collision. We also find several parsec-scale CO shells whose centers are close to either the L1641-N cluster or the V 380 Ori cluster. We propose that these shells were created by multiple winds and/or outflows from cluster young stellar objects, i.e., 'protocluster winds'. One exceptional dust filament located at the western cloud edge lies along a shell; it is presumably part of the expanding shell. Both the cloud-cloud collision and protocluster winds are likely to influence the cloud structure and kinematics in this region.

ON THE STAR FORMATION RATES IN MOLECULAR CLOUDS

International Nuclear Information System (INIS)

Lada, Charles J.; Lombardi, Marco; Alves, Joao F.

2010-01-01

In this paper, we investigate the level of star formation activity within nearby molecular clouds. We employ a uniform set of infrared extinction maps to provide accurate assessments of cloud mass and structure and compare these with inventories of young stellar objects within the clouds. We present evidence indicating that both the yield and rate of star formation can vary considerably in local clouds, independent of their mass and size. We find that the surface density structure of such clouds appears to be important in controlling both these factors. In particular, we find that the star formation rate (SFR) in molecular clouds is linearly proportional to the cloud mass (M 0.8 ) above an extinction threshold of A K ∼ 0.8 mag, corresponding to a gas surface density threshold of Σ gas ∼ 116 M sun pc 2 . We argue that this surface density threshold corresponds to a gas volume density threshold which we estimate to be n(H 2 ) ∼ 10 4 cm -3 . Specifically, we find SFR (M sun yr -1 ) = 4.6 ± 2.6 x 10 -8 M 0.8 (M sun ) for the clouds in our sample. This relation between the rate of star formation and the amount of dense gas in molecular clouds appears to be in excellent agreement with previous observations of both galactic and extragalactic star-forming activity. It is likely the underlying physical relationship or empirical law that most directly connects star formation activity with interstellar gas over many spatial scales within and between individual galaxies. These results suggest that the key to obtaining a predictive understanding of the SFRs in molecular clouds and galaxies is to understand those physical factors which give rise to the dense components of these clouds.

Synergetic cloud fraction determination for SCIAMACHY using MERIS

Directory of Open Access Journals (Sweden)

C. Schlundt

2011-02-01

Full Text Available Since clouds play an essential role in the Earth's climate system, it is important to understand the cloud characteristics as well as their distribution on a global scale using satellite observations. The main scientific objective of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY onboard the ENVISAT satellite is the retrieval of vertical columns of trace gases.

On the one hand, SCIAMACHY has to be sensitive to low variations in trace gas concentrations which means the ground pixel size has to be large enough. On the other hand, such a large pixel size leads to the problem that SCIAMACHY spectra are often contaminated by clouds. SCIAMACHY spectral measurements are not well suitable to derive a reliable sub-pixel cloud fraction that can be used as input parameter for subsequent retrievals of cloud properties or vertical trace gas columns. Therefore, we use MERIS/ENVISAT spectral measurements with its high spatial resolution as sub-pixel information for the determination of MerIs Cloud fRation fOr Sciamachy (MICROS. Since MERIS covers an even broader swath width than SCIAMACHY, no problems in spatial and temporal collocation of measurements occur. This enables the derivation of a SCIAMACHY cloud fraction with an accuracy much higher as compared with other current cloud fractions that are based on SCIAMACHY's PMD (Polarization Measurement Device data.

We present our new developed MICROS algorithm, based on the threshold approach, as well as a qualitative validation of our results with MERIS satellite images for different locations, especially with respect to bright surfaces such as snow/ice and sands. In addition, the SCIAMACHY cloud fractions derived from MICROS are intercompared with other current SCIAMACHY cloud fractions based on different approaches demonstrating a considerable improvement regarding geometric cloud fraction determination using the MICROS algorithm.

An A-Train Climatology of Extratropical Cyclone Clouds

Science.gov (United States)

Posselt, Derek J.; van den Heever, Susan C.; Booth, James F.; Del Genio, Anthony D.; Kahn, Brian; Bauer, Mike

2016-01-01

Extratropical cyclones (ETCs) are the main purveyors of precipitation in the mid-latitudes, especially in winter, and have a significant radiative impact through the clouds they generate. However, general circulation models (GCMs) have trouble representing precipitation and clouds in ETCs, and this might partly explain why current GCMs disagree on to the evolution of these systems in a warming climate. Collectively, the A-train observations of MODIS, CloudSat, CALIPSO, AIRS and AMSR-E have given us a unique perspective on ETCs: over the past 10 years these observations have allowed us to construct a climatology of clouds and precipitation associated with these storms. This has proved very useful for model evaluation as well in studies aimed at improving understanding of moist processes in these dynamically active conditions. Using the A-train observational suite and an objective cyclone and front identification algorithm we have constructed cyclone centric datasets that consist of an observation-based characterization of clouds and precipitation in ETCs and their sensitivity to large scale environments. In this presentation, we will summarize the advances in our knowledge of the climatological properties of cloud and precipitation in ETCs acquired with this unique dataset. In particular, we will present what we have learned about southern ocean ETCs, for which the A-train observations have filled a gap in this data sparse region. In addition, CloudSat and CALIPSO have for the first time provided information on the vertical distribution of clouds in ETCs and across warm and cold fronts. We will also discuss how these observations have helped identify key areas for improvement in moist processes in recent GCMs. Recently, we have begun to explore the interaction between aerosol and cloud cover in ETCs using MODIS, CloudSat and CALIPSO. We will show how aerosols are climatologically distributed within northern hemisphere ETCs, and how this relates to cloud cover.

Exploitation of cloud computing in management of construction projects in Slovakia

Directory of Open Access Journals (Sweden)

Mandičák Tomáš

2016-12-01

Full Text Available The issue of cloud computing is a highly topical issue. Cloud computing represents a new model for information technology (IT services based on the exploitation of Web (it represents a cloud and other application platforms, as well as software as a service. In general, the exploitation of cloud computing in construction project management has several advantages, as demonstrated by several research reports. Currently, research quantifying the exploitation of cloud computing in the Slovak construction industry has not yet been carried out. The article discusses the issue of exploitation of cloud computing in construction project management in Slovakia. The main objective of the research is to confirm whether factors such as size of construction enterprise, owner of construction enterprise and participant of construction project have any impact on the exploitation level of cloud computing in construction project management. It includes confirmation of differences in use between different participants of the construction project or between construction enterprises broken down by size and shareholders.

DETECTION AND CLASSIFICATION OF POLE-LIKE OBJECTS FROM MOBILE MAPPING DATA

Directory of Open Access Journals (Sweden)

K. Fukano

2015-08-01

Full Text Available Laser scanners on a vehicle-based mobile mapping system can capture 3D point-clouds of roads and roadside objects. Since roadside objects have to be maintained periodically, their 3D models are useful for planning maintenance tasks. In our previous work, we proposed a method for detecting cylindrical poles and planar plates in a point-cloud. However, it is often required to further classify pole-like objects into utility poles, streetlights, traffic signals and signs, which are managed by different organizations. In addition, our previous method may fail to extract low pole-like objects, which are often observed in urban residential areas. In this paper, we propose new methods for extracting and classifying pole-like objects. In our method, we robustly extract a wide variety of poles by converting point-clouds into wireframe models and calculating cross-sections between wireframe models and horizontal cutting planes. For classifying pole-like objects, we subdivide a pole-like object into five subsets by extracting poles and planes, and calculate feature values of each subset. Then we apply a supervised machine learning method using feature variables of subsets. In our experiments, our method could achieve excellent results for detection and classification of pole-like objects.

Object Classification Using Airborne Multispectral LiDAR Data

Directory of Open Access Journals (Sweden)

PAN Suoyan

2018-02-01

Full Text Available Airborne multispectral LiDAR system,which obtains surface geometry and spectral data of objects,simultaneously,has become a fast effective,large-scale spatial data acquisition method.Multispectral LiDAR data are characteristics of completeness and consistency of spectrum and spatial geometric information.Support vector machine (SVM,a machine learning method,is capable of classifying objects based on small samples.Therefore,by means of SVM,this paper performs land cover classification using multispectral LiDAR data. First,all independent point cloud with different wavelengths are merged into a single point cloud,where each pixel contains the three-wavelength spectral information.Next,the merged point cloud is converted into range and intensity images.Finally,land-cover classification is performed by means of SVM.All experiments were conducted on the Optech Titan multispectral LiDAR data,containing three individual point cloud collected by 532 nm,1024 nm,and 1550 nm laser beams.Experimental results demonstrate that ①compared to traditional single-wavelength LiDAR data,multispectral LiDAR data provide a promising solution to land use and land cover applications;②SVM is a feasible method for land cover classification of multispectral LiDAR data.

[Treatment of cloud radiative effects in general circulation models

International Nuclear Information System (INIS)

Wang, W.C.

1993-01-01

This is a renewal proposal for an on-going project of the Department of Energy (DOE)/Atmospheric Radiation Measurement (ARM) Program. The objective of the ARM Program is to improve the treatment of radiation-cloud in GCMs so that reliable predictions of the timing and magnitude of greenhouse gas-induced global warming and regional responses can be made. The ARM Program supports two research areas: (I) The modeling and analysis of data related to the parameterization of clouds and radiation in general circulation models (GCMs); and (II) the development of advanced instrumentation for both mapping the three-dimensional structure of the atmosphere and high accuracy/precision radiometric observations. The present project conducts research in area (I) and focuses on GCM treatment of cloud life cycle, optical properties, and vertical overlapping. The project has two tasks: (1) Development and Refinement of GCM Radiation-Cloud Treatment Using ARM Data; and (2) Validation of GCM Radiation-Cloud Treatment

NASA/Max Planck Institute Barium Ion Cloud Project.

Science.gov (United States)

Brence, W. A.; Carr, R. E.; Gerlach, J. C.; Neuss, H.

1973-01-01

NASA and the Max Planck Institute for Extraterrestrial Physics (MPE), Munich, Germany, conducted a cooperative experiment involving the release and study of a barium cloud at 31,500 km altitude near the equatorial plane. The release was made near local magnetic midnight on Sept. 21, 1971. The MPE-built spacecraft contained a canister of 16 kg of Ba CuO mixture, a two-axis magnetometer, and other payload instrumentation. The objectives of the experiment were to investigate the interaction of the ionized barium cloud with the ambient medium and to deduce the properties of electric fields in the proximity of the release. An overview of the project is given to briefly summarize the organization, responsibilities, objectives, instrumentation, and operational aspects of the project.

The Cloud Feedback Model Intercomparison Project (CFMIP) contribution to CMIP6.

Science.gov (United States)

Webb, Mark J.; Andrews, Timothy; Bodas-Salcedo, Alejandro; Bony, Sandrine; Bretherton, Christopher S.; Chadwick, Robin; Chepfer, Helene; Douville, Herve; Good, Peter; Kay, Jennifer E.;

Creating cloud-free Landsat ETM+ data sets in tropical landscapes: cloud and cloud-shadow removal

Science.gov (United States)

Sebastián Martinuzzi; William A. Gould; Olga M. Ramos Gonzalez

2007-01-01

Clouds and cloud shadows are common features of visible and infrared remotelysensed images collected from many parts of the world, particularly in humid and tropical regions. We have developed a simple and semiautomated method to mask clouds and shadows in Landsat ETM+ imagery, and have developed a recent cloud-free composite of multitemporal images for Puerto Rico and...

Non-linear Q-clouds around Kerr black holes

International Nuclear Information System (INIS)

Herdeiro, Carlos; Radu, Eugen; Rúnarsson, Helgi

2014-01-01

Q-balls are regular extended ‘objects’ that exist for some non-gravitating, self-interacting, scalar field theories with a global, continuous, internal symmetry, on Minkowski spacetime. Here, analogous objects are also shown to exist around rotating (Kerr) black holes, as non-linear bound states of a test scalar field. We dub such configurations Q-clouds. We focus on a complex massive scalar field with quartic plus hexic self-interactions. Without the self-interactions, linear clouds have been shown to exist, in synchronous rotation with the black hole horizon, along 1-dimensional subspaces – existence lines – of the Kerr 2-dimensional parameter space. They are zero modes of the superradiant instability. Non-linear Q-clouds, on the other hand, are also in synchronous rotation with the black hole horizon; but they exist on a 2-dimensional subspace, delimited by a minimal horizon angular velocity and by an appropriate existence line, wherein the non-linear terms become irrelevant and the Q-cloud reduces to a linear cloud. Thus, Q-clouds provide an example of scalar bound states around Kerr black holes which, generically, are not zero modes of the superradiant instability. We describe some physical properties of Q-clouds, whose backreaction leads to a new family of hairy black holes, continuously connected to the Kerr family

On the performance of metrics to predict quality in point cloud representations

Science.gov (United States)

Alexiou, Evangelos; Ebrahimi, Touradj

2017-09-01

Point clouds are a promising alternative for immersive representation of visual contents. Recently, an increased interest has been observed in the acquisition, processing and rendering of this modality. Although subjective and objective evaluations are critical in order to assess the visual quality of media content, they still remain open problems for point cloud representation. In this paper we focus our efforts on subjective quality assessment of point cloud geometry, subject to typical types of impairments such as noise corruption and compression-like distortions. In particular, we propose a subjective methodology that is closer to real-life scenarios of point cloud visualization. The performance of the state-of-the-art objective metrics is assessed by considering the subjective scores as the ground truth. Moreover, we investigate the impact of adopting different test methodologies by comparing them. Advantages and drawbacks of every approach are reported, based on statistical analysis. The results and conclusions of this work provide useful insights that could be considered in future experimentation.

A scoping review of cloud computing in healthcare.

Science.gov (United States)

Griebel, Lena; Prokosch, Hans-Ulrich; Köpcke, Felix; Toddenroth, Dennis; Christoph, Jan; Leb, Ines; Engel, Igor; Sedlmayr, Martin

2015-03-19

Cloud computing is a recent and fast growing area of development in healthcare. Ubiquitous, on-demand access to virtually endless resources in combination with a pay-per-use model allow for new ways of developing, delivering and using services. Cloud computing is often used in an "OMICS-context", e.g. for computing in genomics, proteomics and molecular medicine, while other field of application still seem to be underrepresented. Thus, the objective of this scoping review was to identify the current state and hot topics in research on cloud computing in healthcare beyond this traditional domain. MEDLINE was searched in July 2013 and in December 2014 for publications containing the terms "cloud computing" and "cloud-based". Each journal and conference article was categorized and summarized independently by two researchers who consolidated their findings. 102 publications have been analyzed and 6 main topics have been found: telemedicine/teleconsultation, medical imaging, public health and patient self-management, hospital management and information systems, therapy, and secondary use of data. Commonly used features are broad network access for sharing and accessing data and rapid elasticity to dynamically adapt to computing demands. Eight articles favor the pay-for-use characteristics of cloud-based services avoiding upfront investments. Nevertheless, while 22 articles present very general potentials of cloud computing in the medical domain and 66 articles describe conceptual or prototypic projects, only 14 articles report from successful implementations. Further, in many articles cloud computing is seen as an analogy to internet-/web-based data sharing and the characteristics of the particular cloud computing approach are unfortunately not really illustrated. Even though cloud computing in healthcare is of growing interest only few successful implementations yet exist and many papers just use the term "cloud" synonymously for "using virtual machines" or "web

NASA Cloud-Based Climate Data Services

Science.gov (United States)

McInerney, M. A.; Schnase, J. L.; Duffy, D. Q.; Tamkin, G. S.; Strong, S.; Ripley, W. D., III; Thompson, J. H.; Gill, R.; Jasen, J. E.; Samowich, B.; Pobre, Z.; Salmon, E. M.; Rumney, G.; Schardt, T. D.

2012-12-01

Cloud-based scientific data services are becoming an important part of NASA's mission. Our technological response is built around the concept of specialized virtual climate data servers, repetitive cloud provisioning, image-based deployment and distribution, and virtualization-as-a-service (VaaS). A virtual climate data server (vCDS) is an Open Archive Information System (OAIS) compliant, iRODS-based data server designed to support a particular type of scientific data collection. iRODS is data grid middleware that provides policy-based control over collection-building, managing, querying, accessing, and preserving large scientific data sets. We have deployed vCDS Version 1.0 in the Amazon EC2 cloud using S3 object storage and are using the system to deliver a subset of NASA's Intergovernmental Panel on Climate Change (IPCC) data products to the latest CentOS federated version of Earth System Grid Federation (ESGF), which is also running in the Amazon cloud. vCDS-managed objects are exposed to ESGF through FUSE (Filesystem in User Space), which presents a POSIX-compliant filesystem abstraction to applications such as the ESGF server that require such an interface. A vCDS manages data as a distinguished collection for a person, project, lab, or other logical unit. A vCDS can manage a collection across multiple storage resources using rules and microservices to enforce collection policies. And a vCDS can federate with other vCDSs to manage multiple collections over multiple resources, thereby creating what can be thought of as an ecosystem of managed collections. With the vCDS approach, we are trying to enable the full information lifecycle management of scientific data collections and make tractable the task of providing diverse climate data services. In this presentation, we describe our approach, experiences, lessons learned, and plans for the future.; (A) vCDS/ESG system stack. (B) Conceptual architecture for NASA cloud-based data services.

Point Cloud Based Change Detection - an Automated Approach for Cloud-based Services

Science.gov (United States)

Collins, Patrick; Bahr, Thomas

2016-04-01

The fusion of stereo photogrammetric point clouds with LiDAR data or terrain information derived from SAR interferometry has a significant potential for 3D topographic change detection. In the present case study latest point cloud generation and analysis capabilities are used to examine a landslide that occurred in the village of Malin in Maharashtra, India, on 30 July 2014, and affected an area of ca. 44.000 m2. It focuses on Pléiades high resolution satellite imagery and the Airbus DS WorldDEMTM as a product of the TanDEM-X mission. This case study was performed using the COTS software package ENVI 5.3. Integration of custom processes and automation is supported by IDL (Interactive Data Language). Thus, ENVI analytics is running via the object-oriented and IDL-based ENVITask API. The pre-event topography is represented by the WorldDEMTM product, delivered with a raster of 12 m x 12 m and based on the EGM2008 geoid (called pre-DEM). For the post-event situation a Pléiades 1B stereo image pair of the AOI affected was obtained. The ENVITask "GeneratePointCloudsByDenseImageMatching" was implemented to extract passive point clouds in LAS format from the panchromatic stereo datasets: • A dense image-matching algorithm is used to identify corresponding points in the two images. • A block adjustment is applied to refine the 3D coordinates that describe the scene geometry. • Additionally, the WorldDEMTM was input to constrain the range of heights in the matching area, and subsequently the length of the epipolar line. The "PointCloudFeatureExtraction" task was executed to generate the post-event digital surface model from the photogrammetric point clouds (called post-DEM). Post-processing consisted of the following steps: • Adding the geoid component (EGM 2008) to the post-DEM. • Pre-DEM reprojection to the UTM Zone 43N (WGS-84) coordinate system and resizing. • Subtraction of the pre-DEM from the post-DEM. • Filtering and threshold based classification of

Discovery of a protostar in the Large Magellanic Cloud

International Nuclear Information System (INIS)

Gatley, I.; Becklin, E.E.; Hyland, A.R.; Jones, T.J.

1981-01-01

A near infrared search of the H II region/molecular cloud complex N 159 in the Large Magellanic Cloud has revealed a very red (H-K = 2.1, K-L' = 2.7) compact object. The location, brightness, colour and 2.1 to 2.4 μm spectrum of this source suggest that it is very young, and similar to the galactic infrared 'protostars'. This is the first identification of an infrared protostar in an external galaxy. Its discovery provides direct evidence of current star formation in the Large Magellanic Cloud, and suggests that regions of star formation in external galaxies will appear similar to those in the Milky Way. (author)

Zen of cloud learning cloud computing by examples on Microsoft Azure

CERN Document Server

Bai, Haishi

2014-01-01

Zen of Cloud: Learning Cloud Computing by Examples on Microsoft Azure provides comprehensive coverage of the essential theories behind cloud computing and the Windows Azure cloud platform. Sharing the author's insights gained while working at Microsoft's headquarters, it presents nearly 70 end-to-end examples with step-by-step guidance on implementing typical cloud-based scenarios.The book is organized into four sections: cloud service fundamentals, cloud solutions, devices and cloud, and system integration and project management. Each chapter contains detailed exercises that provide readers w

Technologies and Business Value of Cloud Computing: Strategy for the Department of Information Processing

OpenAIRE

Manyando, Obyster

2013-01-01

This research focuses on the area of cloud computing, an important research area in computer and service science. The general aim of this research is to emphasize the business value of cloud computing to businesses. The objective of this research is to explore the economic benefits of cloud computing in order to promote its use in business and the education sector. Consequently, the research recommends the adoption of cloud computing by the Kemi-Tornio University of Applied Sciences. The ...

TURBULENCE DECAY AND CLOUD CORE RELAXATION IN MOLECULAR CLOUDS

International Nuclear Information System (INIS)

Gao, Yang; Law, Chung K.; Xu, Haitao

2015-01-01

The turbulent motion within molecular clouds is a key factor controlling star formation. Turbulence supports molecular cloud cores from evolving to gravitational collapse and hence sets a lower bound on the size of molecular cloud cores in which star formation can occur. On the other hand, without a continuous external energy source maintaining the turbulence, such as in molecular clouds, the turbulence decays with an energy dissipation time comparable to the dynamic timescale of clouds, which could change the size limits obtained from Jean's criterion by assuming constant turbulence intensities. Here we adopt scaling relations of physical variables in decaying turbulence to analyze its specific effects on the formation of stars. We find that the decay of turbulence provides an additional approach for Jeans' criterion to be achieved, after which gravitational infall governs the motion of the cloud core. This epoch of turbulence decay is defined as cloud core relaxation. The existence of cloud core relaxation provides a more complete understanding of the effect of the competition between turbulence and gravity on the dynamics of molecular cloud cores and star formation

Review of Cloud Computing and existing Frameworks for Cloud adoption

OpenAIRE

Chang, Victor; Walters, Robert John; Wills, Gary

2014-01-01

This paper presents a selected review for Cloud Computing and explains the benefits and risks of adopting Cloud Computing in a business environment. Although all the risks identified may be associated with two major Cloud adoption challenges, a framework is required to support organisations as they begin to use Cloud and minimise risks of Cloud adoption. Eleven Cloud Computing frameworks are investigated and a comparison of their strengths and limitations is made; the result of the comparison...

Smashing a Jet into a Cloud to Form Stars

Science.gov (United States)

Kohler, Susanna

2017-12-01

What happens when the highly energetic jet from the center of an active galaxy rams into surrounding clouds of gas and dust? A new study explores whether this might be a way to form stars.The authors simulations at an intermediate (top) and final (bottom) stage show the compression in the gas cloud as a jet (red) enters from the left. Undisturbed cloud material is shown in blue, whereas green corresponds to cold, compressed gas actively forming stars. [Fragile et al. 2017]Impacts of FeedbackCorrelation between properties of supermassive black holes and their host galaxies suggest that there is some means of communication between them. For this reason, we suspect that feedback from an active galactic nucleus (AGN) in the form of jets, for instance controls the size of the galaxy by influencing star formation. But how does this process work?AGN feedback can be either negative or positive. In negative feedback, the gas necessary for forming stars is heated or dispersed by the jet, curbing or halting star formation. In positive feedback, jets propagate through the surrounding gas with energies high enough to create compression in the gas, but not so high that they heat it. The increased density can cause the gas to collapse, thereby triggering star formation.In a recent study, a team of scientists led by Chris Fragile (College of Charleston) modeled what happens when an enormous AGN jet slams into a dwarf-galaxy-sized, inactive cloud of gas. In particular, the team explored the possibility of star-forming positive feedback with the goal of reproducing recent observations of something called Minkowskis Object, a stellar nursery located at the endpoint of a radio jet emitted from the active galaxy NGC 541.The star formation rate in the simulated cloud increases dramatically as a result of the jets impact, reaching the rate currently observed for Minkowskis Objects within 20 million years. [Fragile et al. 2017]Triggering Stellar BirthFragile and collaborators used a

Point-Cloud Compression for Vehicle-Based Mobile Mapping Systems Using Portable Network Graphics

Science.gov (United States)

Kohira, K.; Masuda, H.

2017-09-01

A mobile mapping system is effective for capturing dense point-clouds of roads and roadside objects Point-clouds of urban areas, residential areas, and arterial roads are useful for maintenance of infrastructure, map creation, and automatic driving. However, the data size of point-clouds measured in large areas is enormously large. A large storage capacity is required to store such point-clouds, and heavy loads will be taken on network if point-clouds are transferred through the network. Therefore, it is desirable to reduce data sizes of point-clouds without deterioration of quality. In this research, we propose a novel point-cloud compression method for vehicle-based mobile mapping systems. In our compression method, point-clouds are mapped onto 2D pixels using GPS time and the parameters of the laser scanner. Then, the images are encoded in the Portable Networking Graphics (PNG) format and compressed using the PNG algorithm. In our experiments, our method could efficiently compress point-clouds without deteriorating the quality.

Cloud CCN feedback

International Nuclear Information System (INIS)

Hudson, J.G.

1992-01-01

Cloud microphysics affects cloud albedo precipitation efficiency and the extent of cloud feedback in response to global warming. Compared to other cloud parameters, microphysics is unique in its large range of variability and the fact that much of the variability is anthropogenic. Probably the most important determinant of cloud microphysics is the spectra of cloud condensation nuclei (CCN) which display considerable variability and have a large anthropogenic component. When analyzed in combination three field observation projects display the interrelationship between CCN and cloud microphysics. CCN were measured with the Desert Research Institute (DRI) instantaneous CCN spectrometer. Cloud microphysical measurements were obtained with the National Center for Atmospheric Research Lockheed Electra. Since CCN and cloud microphysics each affect the other a positive feedback mechanism can result

Identification of clouds and aurorae in optical data images

CERN Document Server

Seviour, R; Honary, F

2003-01-01

In this paper we present an automatic image recognition technique used to identify clouds and aurorae in digital images, taken with a CCD all-sky imager. The image recognition algorithm uses image segmentation to generate a binary block object image. Object analysis is then performed on the binary block image, the results of which are used to assess whether clouds, aurorae and stars are present in the original image. The need for such an algorithm arises because the optical study of particle precipitation into the Earth's atmosphere by the Ionosphere and Radio Propagation Group at Lancaster generates vast data-sets, over 25 000 images/year, making manual classification of all the images impractical.

A scalable and multi-purpose point cloud server (PCS) for easier and faster point cloud data management and processing

Science.gov (United States)

Cura, Rémi; Perret, Julien; Paparoditis, Nicolas

2017-05-01

In addition to more traditional geographical data such as images (rasters) and vectors, point cloud data are becoming increasingly available. Such data are appreciated for their precision and true three-Dimensional (3D) nature. However, managing point clouds can be difficult due to scaling problems and specificities of this data type. Several methods exist but are usually fairly specialised and solve only one aspect of the management problem. In this work, we propose a comprehensive and efficient point cloud management system based on a database server that works on groups of points (patches) rather than individual points. This system is specifically designed to cover the basic needs of point cloud users: fast loading, compressed storage, powerful patch and point filtering, easy data access and exporting, and integrated processing. Moreover, the proposed system fully integrates metadata (like sensor position) and can conjointly use point clouds with other geospatial data, such as images, vectors, topology and other point clouds. Point cloud (parallel) processing can be done in-base with fast prototyping capabilities. Lastly, the system is built on open source technologies; therefore it can be easily extended and customised. We test the proposed system with several billion points obtained from Lidar (aerial and terrestrial) and stereo-vision. We demonstrate loading speeds in the ˜50 million pts/h per process range, transparent-for-user and greater than 2 to 4:1 compression ratio, patch filtering in the 0.1 to 1 s range, and output in the 0.1 million pts/s per process range, along with classical processing methods, such as object detection.

Dense interstellar cloud chemistry: Basic issues and possible dynamical solution

International Nuclear Information System (INIS)

Prasad, S.S.; Heere, K.R.; Tarafdar, S.P.

1989-01-01

Standing at crossroad of enthusiasm and frustration, dense intertellar cloud chemistry has a squarely posed fundamental problem: Why do the grains appear to play at best a minor role in the chemistry? Grain surface chemistry creates considerable difficulties when the authors treat dense clouds as static objects and ignore the implications of the processes by which the clouds became dense in the first place. A new generation of models which treat chemical and dynamical evolutions concurrently are therefore presented as possible solution to the current frustrations. The proposed modeling philosophy and agenda could make the next decade quite exciting for interstellar chemistry

Cloud Governance

DEFF Research Database (Denmark)

Berthing, Hans Henrik

Denne præsentation beskriver fordele og værdier ved anvendelse af Cloud Computing. Endvidere inddrager resultater fra en række internationale analyser fra ISACA om Cloud Computing.......Denne præsentation beskriver fordele og værdier ved anvendelse af Cloud Computing. Endvidere inddrager resultater fra en række internationale analyser fra ISACA om Cloud Computing....

Comets - Mementos of creation

International Nuclear Information System (INIS)

Sagan, C.; Druyan, A.

1989-01-01

Consideration is given to the Kant-Laplace hypothesis that the sun once had a ring system from which the planets condensed. It is suggested that the theory is supported by the IRAS observation of an accretion disk around Vega, which implies that ordinary stars are surrounded by a disk during and immediately after formation. A model for planetary formation from a disk is presented. The possibility that cometary bodies may have been ejected into the Oort Cloud during planetary formation is examined

A Speculation into the Origin of Neutral Globules In Planetary Nebulae: Could the Helix's Comets Really Be Comets?

OpenAIRE

Gussie, Grant

1995-01-01

A novel explanation for the origin of the cometary globules within NGC 7293 (the "Helix" planetary nebula) is examined; that these globules originate as massive cometary bodies at large astrocentric radii. The mass of such hypothetical cometary bodies would have to be several orders of magnitude larger than any such bodies observed in our solar system in order to supply the observed mass of neutral gas. It is however shown that comets at "outer Oort cloud" like distances are likely to survive...

Comparisons of Satellite-Deduced Overlapping Cloud Properties and CALIPSO CloudSat Data

Science.gov (United States)

Chang, Fu-Lung; Minnis, Patrick; Lin, Bing; Sun-Mack, Sunny

2010-01-01

Introduction to the overlapped cloud properties derived from polar-orbiting (MODIS) and geostationary (GOES-12, -13, Meteosat-8, -9, etc.) meteorological satellites, which are produced at the NASA Langley Research Center (LaRC) cloud research & development team (NASA lead scientist: Dr. Patrick Minnis). Comparison of the LaRC CERES MODIS Edition-3 overlapped cloud properties to the CALIPSO and the CloudSat active sensing data. High clouds and overlapped clouds occur frequently as deduced by CALIPSO (44 & 25%), CloudSat (25 & 4%), and MODIS (37 & 6%). Large fractions of optically-thin cirrus and overlapped clouds are deduced from CALIPSO, but much smaller fractions are from CloudSat and MODIS. For overlapped clouds, the averaged upper-layer CTHs are about 12.8 (CALIPSO), 10.9 (CloudSat) and 10 km (MODIS), and the averaged lower-layer CTHs are about 3.6 (CALIPSO), 3.2 (CloudSat) and 3.9 km (MODIS). Based on comparisons of upper and lower-layer cloud properties as deduced from the MODIS, CALIPSO and CloudSat data, more enhanced passive satellite methods for retrieving thin cirrus and overlapped cloud properties are needed and are under development.

Securing the Cloud Cloud Computer Security Techniques and Tactics

CERN Document Server

Winkler, Vic (JR)

2011-01-01

As companies turn to cloud computing technology to streamline and save money, security is a fundamental concern. Loss of certain control and lack of trust make this transition difficult unless you know how to handle it. Securing the Cloud discusses making the move to the cloud while securing your peice of it! The cloud offers felxibility, adaptability, scalability, and in the case of security-resilience. This book details the strengths and weaknesses of securing your company's information with different cloud approaches. Attacks can focus on your infrastructure, communications network, data, o

Cloud Service Scheduling Algorithm Research and Optimization

Directory of Open Access Journals (Sweden)

Hongyan Cui

2017-01-01

Full Text Available We propose a cloud service scheduling model that is referred to as the Task Scheduling System (TSS. In the user module, the process time of each task is in accordance with a general distribution. In the task scheduling module, we take a weighted sum of makespan and flowtime as the objective function and use an Ant Colony Optimization (ACO and a Genetic Algorithm (GA to solve the problem of cloud task scheduling. Simulation results show that the convergence speed and output performance of our Genetic Algorithm-Chaos Ant Colony Optimization (GA-CACO are optimal.

Globules, dark clouds, and low mass pre-main sequence stars

International Nuclear Information System (INIS)

Hyland, A.R.

1981-01-01

The current observational and theoretical literature on Bok globules and their relationship to star formation is reviewed. Recent observations of globules at optical, infrared, and far infrared wavelengths are shown to provide important constraints on their structure and evolutionary status, and the suggestion that many globules are gravitationally unstable is seriously questioned. Dark clouds associated with T associations are well-known sites of recent and continuing star formation. In recent years molecular observations and far infrared surveys have provided maps of such regions from which possible sites of star formation may be identified. Optical (Hα) and near infrared surveys have enabled a clear identification of pre-main sequence (PMS) objects within the clouds. Methods of distinguishing these from background objects and the nature of their infrared excesses are examined in the light of recent observations in the near and far infrared. The perennial question as to the existence of anomalous reddening within dark clouds is also investigated. (Auth.)

Warm gas towards young stellar objects in Corona Australis

DEFF Research Database (Denmark)

Lindberg, Johan; Jørgensen, Jes Kristian; D. Green, Joel

2014-01-01

The effects of external irradiation on the chemistry and physics in the protostellar envelope around low-mass young stellar objects are poorly understood. The Corona Australis star-forming region contains the R CrA dark cloud, comprising several low-mass protostellar cores irradiated by an interm......The effects of external irradiation on the chemistry and physics in the protostellar envelope around low-mass young stellar objects are poorly understood. The Corona Australis star-forming region contains the R CrA dark cloud, comprising several low-mass protostellar cores irradiated...... by an intermediate-mass young star. We study the effects on the warm gas and dust in a group of low-mass young stellar objects from the irradiation by the young luminous Herbig Be star R CrA. Herschel/PACS far-infrared datacubes of two low-mass star-forming regions in the R CrA dark cloud are presented...... Be star R CrA. Our results show that a nearby luminous star does not increase the molecular excitation temperatures in the warm gas around a young stellar object (YSO). However, the emission from photodissociation products of H2O, such as OH and O, is enhanced in the warm gas associated...

Multilayer Cloud Detection with the MODIS Near-Infrared Water Vapor Absorption Band

Science.gov (United States)

Wind, Galina; Platnick, Steven; King, Michael D.; Hubanks, Paul A,; Pavolonis, Michael J.; Heidinger, Andrew K.; Yang, Ping; Baum, Bryan A.

2009-01-01

Data Collection 5 processing for the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the NASA Earth Observing System EOS Terra and Aqua spacecraft includes an algorithm for detecting multilayered clouds in daytime. The main objective of this algorithm is to detect multilayered cloud scenes, specifically optically thin ice cloud overlying a lower-level water cloud, that presents difficulties for retrieving cloud effective radius using single layer plane-parallel cloud models. The algorithm uses the MODIS 0.94 micron water vapor band along with CO2 bands to obtain two above-cloud precipitable water retrievals, the difference of which, in conjunction with additional tests, provides a map of where multilayered clouds might potentially exist. The presence of a multilayered cloud results in a large difference in retrievals of above-cloud properties between the CO2 and the 0.94 micron methods. In this paper the MODIS multilayered cloud algorithm is described, results of using the algorithm over example scenes are shown, and global statistics for multilayered clouds as observed by MODIS are discussed. A theoretical study of the algorithm behavior for simulated multilayered clouds is also given. Results are compared to two other comparable passive imager methods. A set of standard cloudy atmospheric profiles developed during the course of this investigation is also presented. The results lead to the conclusion that the MODIS multilayer cloud detection algorithm has some skill in identifying multilayered clouds with different thermodynamic phases

Cloud management and security

CERN Document Server

Abbadi, Imad M

2014-01-01

Written by an expert with over 15 years' experience in the field, this book establishes the foundations of Cloud computing, building an in-depth and diverse understanding of the technologies behind Cloud computing. In this book, the author begins with an introduction to Cloud computing, presenting fundamental concepts such as analyzing Cloud definitions, Cloud evolution, Cloud services, Cloud deployment types and highlighting the main challenges. Following on from the introduction, the book is divided into three parts: Cloud management, Cloud security, and practical examples. Part one presents the main components constituting the Cloud and federated Cloud infrastructure(e.g., interactions and deployment), discusses management platforms (resources and services), identifies and analyzes the main properties of the Cloud infrastructure, and presents Cloud automated management services: virtual and application resource management services. Part two analyzes the problem of establishing trustworthy Cloud, discuss...

Cloud computing patterns fundamentals to design, build, and manage cloud applications

CERN Document Server

Fehling, Christoph; Retter, Ralph; Schupeck, Walter; Arbitter, Peter

2014-01-01

The current work provides CIOs, software architects, project managers, developers, and cloud strategy initiatives with a set of architectural patterns that offer nuggets of advice on how to achieve common cloud computing-related goals. The cloud computing patterns capture knowledge and experience in an abstract format that is independent of concrete vendor products. Readers are provided with a toolbox to structure cloud computing strategies and design cloud application architectures. By using this book cloud-native applications can be implemented and best suited cloud vendors and tooling for i

The formation of a Spitzer bubble RCW 79 triggered by a cloud-cloud collision

Science.gov (United States)

Ohama, Akio; Kohno, Mikito; Hasegawa, Keisuke; Torii, Kazufumi; Nishimura, Atsushi; Hattori, Yusuke; Hayakawa, Takahiro; Inoue, Tsuyoshi; Sano, Hidetoshi; Yamamoto, Hiroaki; Tachihara, Kengo; Fukui, Yasuo

2018-05-01

Understanding the mechanism of O-star formation is one of the most important current issues in astrophysics. Also an issue of keen interest is how O stars affect their surroundings and trigger secondary star formation. An H II region RCW 79 is one of the typical Spitzer bubbles alongside RCW 120. New observations of CO J = 1-0 emission with Mopra and NANTEN2 revealed that molecular clouds are associated with RCW 79 in four velocity components over a velocity range of 20 km s-1. We hypothesize that two of the clouds collided with each other and the collision triggered the formation of 12 O stars inside the bubble and the formation of 54 low-mass young stellar objects along the bubble wall. The collision is supported by observational signatures of bridges connecting different velocity components in the colliding clouds. The whole collision process happened over a timescale of ˜3 Myr. RCW 79 has a larger size by a factor of 30 in the projected area than RCW 120 with a single O star, and the large size favored formation of the 12 O stars due to the greater accumulated gas in the collisional shock compression.

Military clouds: utilization of cloud computing systems at the battlefield

Science.gov (United States)

Süleyman, Sarıkürk; Volkan, Karaca; İbrahim, Kocaman; Ahmet, Şirzai

2012-05-01

Cloud computing is known as a novel information technology (IT) concept, which involves facilitated and rapid access to networks, servers, data saving media, applications and services via Internet with minimum hardware requirements. Use of information systems and technologies at the battlefield is not new. Information superiority is a force multiplier and is crucial to mission success. Recent advances in information systems and technologies provide new means to decision makers and users in order to gain information superiority. These developments in information technologies lead to a new term, which is known as network centric capability. Similar to network centric capable systems, cloud computing systems are operational today. In the near future extensive use of military clouds at the battlefield is predicted. Integrating cloud computing logic to network centric applications will increase the flexibility, cost-effectiveness, efficiency and accessibility of network-centric capabilities. In this paper, cloud computing and network centric capability concepts are defined. Some commercial cloud computing products and applications are mentioned. Network centric capable applications are covered. Cloud computing supported battlefield applications are analyzed. The effects of cloud computing systems on network centric capability and on the information domain in future warfare are discussed. Battlefield opportunities and novelties which might be introduced to network centric capability by cloud computing systems are researched. The role of military clouds in future warfare is proposed in this paper. It was concluded that military clouds will be indispensible components of the future battlefield. Military clouds have the potential of improving network centric capabilities, increasing situational awareness at the battlefield and facilitating the settlement of information superiority.

Clustering, randomness, and regularity in cloud fields. 4: Stratocumulus cloud fields

Science.gov (United States)

Lee, J.; Chou, J.; Weger, R. C.; Welch, R. M.

1994-01-01

To complete the analysis of the spatial distribution of boundary layer cloudiness, the present study focuses on nine stratocumulus Landsat scenes. The results indicate many similarities between stratocumulus and cumulus spatial distributions. Most notably, at full spatial resolution all scenes exhibit a decidedly clustered distribution. The strength of the clustering signal decreases with increasing cloud size; the clusters themselves consist of a few clouds (less than 10), occupy a small percentage of the cloud field area (less than 5%), contain between 20% and 60% of the cloud field population, and are randomly located within the scene. In contrast, stratocumulus in almost every respect are more strongly clustered than are cumulus cloud fields. For instance, stratocumulus clusters contain more clouds per cluster, occupy a larger percentage of the total area, and have a larger percentage of clouds participating in clusters than the corresponding cumulus examples. To investigate clustering at intermediate spatial scales, the local dimensionality statistic is introduced. Results obtained from this statistic provide the first direct evidence for regularity among large (more than 900 m in diameter) clouds in stratocumulus and cumulus cloud fields, in support of the inhibition hypothesis of Ramirez and Bras (1990). Also, the size compensated point-to-cloud cumulative distribution function statistic is found to be necessary to obtain a consistent description of stratocumulus cloud distributions. A hypothesis regarding the underlying physical mechanisms responsible for cloud clustering is presented. It is suggested that cloud clusters often arise from 4 to 10 triggering events localized within regions less than 2 km in diameter and randomly distributed within the cloud field. As the size of the cloud surpasses the scale of the triggering region, the clustering signal weakens and the larger cloud locations become more random.

Clustering, randomness, and regularity in cloud fields. 4. Stratocumulus cloud fields

Science.gov (United States)

Lee, J.; Chou, J.; Weger, R. C.; Welch, R. M.

1994-07-01

To complete the analysis of the spatial distribution of boundary layer cloudiness, the present study focuses on nine stratocumulus Landsat scenes. The results indicate many similarities between stratocumulus and cumulus spatial distributions. Most notably, at full spatial resolution all scenes exhibit a decidedly clustered distribution. The strength of the clustering signal decreases with increasing cloud size; the clusters themselves consist of a few clouds (less than 10), occupy a small percentage of the cloud field area (less than 5%), contain between 20% and 60% of the cloud field population, and are randomly located within the scene. In contrast, stratocumulus in almost every respect are more strongly clustered than are cumulus cloud fields. For instance, stratocumulus clusters contain more clouds per cluster, occupy a larger percentage of the total area, and have a larger percentage of clouds participating in clusters than the corresponding cumulus examples. To investigate clustering at intermediate spatial scales, the local dimensionality statistic is introduced. Results obtained from this statistic provide the first direct evidence for regularity among large (>900 m in diameter) clouds in stratocumulus and cumulus cloud fields, in support of the inhibition hypothesis of Ramirez and Bras (1990). Also, the size compensated point-to-cloud cumulative distribution function statistic is found to be necessary to obtain a consistent description of stratocumulus cloud distributions. A hypothesis regarding the underlying physical mechanisms responsible for cloud clustering is presented. It is suggested that cloud clusters often arise from 4 to 10 triggering events localized within regions less than 2 km in diameter and randomly distributed within the cloud field. As the size of the cloud surpasses the scale of the triggering region, the clustering signal weakens and the larger cloud locations become more random.

Cloud blueprints for integrating and managing cloud federations

NARCIS (Netherlands)

Papazoglou, M.; Heisel, M.

2012-01-01

Contemporary cloud technologies face insurmountable obstacles. They follow a pull-based, producer-centric trajectory to development where cloud consumers have to ‘squeeze and bolt’ applications onto cloud APIs. They also introduce a monolithic SaaS/PaaS/IaaS stack where a one-size-fits-all mentality

Galaxy CloudMan: delivering cloud compute clusters.

Science.gov (United States)

Afgan, Enis; Baker, Dannon; Coraor, Nate; Chapman, Brad; Nekrutenko, Anton; Taylor, James

2010-12-21

Widespread adoption of high-throughput sequencing has greatly increased the scale and sophistication of computational infrastructure needed to perform genomic research. An alternative to building and maintaining local infrastructure is "cloud computing", which, in principle, offers on demand access to flexible computational infrastructure. However, cloud computing resources are not yet suitable for immediate "as is" use by experimental biologists. We present a cloud resource management system that makes it possible for individual researchers to compose and control an arbitrarily sized compute cluster on Amazon's EC2 cloud infrastructure without any informatics requirements. Within this system, an entire suite of biological tools packaged by the NERC Bio-Linux team (http://nebc.nerc.ac.uk/tools/bio-linux) is available for immediate consumption. The provided solution makes it possible, using only a web browser, to create a completely configured compute cluster ready to perform analysis in less than five minutes. Moreover, we provide an automated method for building custom deployments of cloud resources. This approach promotes reproducibility of results and, if desired, allows individuals and labs to add or customize an otherwise available cloud system to better meet their needs. The expected knowledge and associated effort with deploying a compute cluster in the Amazon EC2 cloud is not trivial. The solution presented in this paper eliminates these barriers, making it possible for researchers to deploy exactly the amount of computing power they need, combined with a wealth of existing analysis software, to handle the ongoing data deluge.

Cloud blueprint : A model-driven approach to configuring federated clouds

NARCIS (Netherlands)

Papazoglou, M.; Abello, A.; Bellatreche, L.; Benatallah, B.

2012-01-01

Current cloud solutions are fraught with problems. They introduce a monolithic cloud stack that imposes vendor lock-in and donot permit developers to mix and match services freely from diverse cloud service tiers and configure them dynamically to address application needs. Cloud blueprinting is a

Building cross-platform apps using Titanium, Alloy, and Appcelerator cloud services

CERN Document Server

Saunders, Aaron

2014-01-01

Skip Objective-C and Java to get your app to market faster, using the skills you already have Building Cross-Platform Apps using Titanium, Alloy, and Appcelerator Cloud Services shows you how to build cross-platform iOS and Android apps without learning Objective-C or Java. With detailed guidance given toward using the Titanium Mobile Platform and Appcelerator Cloud Services, you will quickly develop the skills to build real, native apps- not web apps-using existing HTML, CSS, and JavaScript know-how. This guide takes you step-by-step through the creation of a photo-sharing app that leverages

Strategic Plan for a Scientific Cloud Computing infrastructure for Europe

CERN Document Server

Lengert, Maryline

2011-01-01

Here we present the vision, concept and direction for forming a European Industrial Strategy for a Scientific Cloud Computing Infrastructure to be implemented by 2020. This will be the framework for decisions and for securing support and approval in establishing, initially, an R&D European Cloud Computing Infrastructure that serves the need of European Research Area (ERA ) and Space Agencies. This Cloud Infrastructure will have the potential beyond this initial user base to evolve to provide similar services to a broad range of customers including government and SMEs. We explain how this plan aims to support the broader strategic goals of our organisations and identify the benefits to be realised by adopting an industrial Cloud Computing model. We also outline the prerequisites and commitment needed to achieve these objectives.

Thin Cloud Detection Method by Linear Combination Model of Cloud Image

Science.gov (United States)

Liu, L.; Li, J.; Wang, Y.; Xiao, Y.; Zhang, W.; Zhang, S.

2018-04-01

The existing cloud detection methods in photogrammetry often extract the image features from remote sensing images directly, and then use them to classify images into cloud or other things. But when the cloud is thin and small, these methods will be inaccurate. In this paper, a linear combination model of cloud images is proposed, by using this model, the underlying surface information of remote sensing images can be removed. So the cloud detection result can become more accurate. Firstly, the automatic cloud detection program in this paper uses the linear combination model to split the cloud information and surface information in the transparent cloud images, then uses different image features to recognize the cloud parts. In consideration of the computational efficiency, AdaBoost Classifier was introduced to combine the different features to establish a cloud classifier. AdaBoost Classifier can select the most effective features from many normal features, so the calculation time is largely reduced. Finally, we selected a cloud detection method based on tree structure and a multiple feature detection method using SVM classifier to compare with the proposed method, the experimental data shows that the proposed cloud detection program in this paper has high accuracy and fast calculation speed.

Size-density relations in dark clouds: Non-LTE effects

International Nuclear Information System (INIS)

Maloney, P.

1986-01-01

One of the major goals of molecular astronomy has been to understand the physics and dynamics of dense interstellar clouds. Because the interpretation of observations of giant molecular clouds is complicated by their very complex structure and the dynamical effects of star formation, a number of studies have concentrated on dark clouds. Leung, Kutner and Mead (1982) (hereafter LKM) and Myers (1983), in studies of CO and NH 3 emission, concluded that dark clouds exhibit significant correlations between linewidth and cloud radius of the form delta v varies as R(0.5) and between mean density and radius of the form n varies as R(-1), as originally suggested by Larson (1981). This result suggests that these objects are in virial equilibrium. However, the mean densities inferred from the CO data of LKM are based on an local thermodynamic equilibrium (LTE) analysis of their 13CO data. At the very low mean densities inferred by LKM for the larger clouds in their samples, the assumption of LTE becomes very questionable. As most of the range in R in the density-size correlation comes from the clouds observed in CO, it seems worthwhile to examine how non-LTE effects will influence the derived densities. Microturbulent models of inhomogeneous clouds of varying central concentration with the linewidth-size and mean density-size relations found by Myers show sub-thermal excitation of the 13CO line in the larger clouds, with the result that LTE analysis considerbly underestimates the actual column density. A more general approach which doesn't require detailed modeling of the clouds is to consider whether the observed T/sub R/*(13CO)/T/sub R/*(12CO) ratios in the clouds studied by LKM are in the range where the LTE-derived optical depths be seriously in error due to sub-thermal excitation of the 13CO molecule

Space Situational Awareness Data Processing Scalability Utilizing Google Cloud Services

Science.gov (United States)

Greenly, D.; Duncan, M.; Wysack, J.; Flores, F.

Space Situational Awareness (SSA) is a fundamental and critical component of current space operations. The term SSA encompasses the awareness, understanding and predictability of all objects in space. As the population of orbital space objects and debris increases, the number of collision avoidance maneuvers grows and prompts the need for accurate and timely process measures. The SSA mission continually evolves to near real-time assessment and analysis demanding the need for higher processing capabilities. By conventional methods, meeting these demands requires the integration of new hardware to keep pace with the growing complexity of maneuver planning algorithms. SpaceNav has implemented a highly scalable architecture that will track satellites and debris by utilizing powerful virtual machines on the Google Cloud Platform. SpaceNav algorithms for processing CDMs outpace conventional means. A robust processing environment for tracking data, collision avoidance maneuvers and various other aspects of SSA can be created and deleted on demand. Migrating SpaceNav tools and algorithms into the Google Cloud Platform will be discussed and the trials and tribulations involved. Information will be shared on how and why certain cloud products were used as well as integration techniques that were implemented. Key items to be presented are: 1.Scientific algorithms and SpaceNav tools integrated into a scalable architecture a) Maneuver Planning b) Parallel Processing c) Monte Carlo Simulations d) Optimization Algorithms e) SW Application Development/Integration into the Google Cloud Platform 2. Compute Engine Processing a) Application Engine Automated Processing b) Performance testing and Performance Scalability c) Cloud MySQL databases and Database Scalability d) Cloud Data Storage e) Redundancy and Availability

OPTICAL AND NEAR-INFRARED SHOCKS IN THE L988 CLOUD COMPLEX

International Nuclear Information System (INIS)

Walawender, J.; Reipurth, B.; Bally, J.

2013-01-01

We have searched the Lynds 988 dark cloud complex for optical (Hα and [S II]) and near-IR (H 2 2.12 μm) shocks from protostellar outflows. We find 20 new Herbig-Haro objects and 6 new H 2 shocks (MHO objects), 3 of which are cross detections. Using the morphology in the optical and near-IR, we connect several of these shocks into at least five distinct outflow systems and identify their source protostars from catalogs of infrared sources. Two outflows in the cloud, from IRAS 21014+5001 and IRAS 21007+4951, are in excess of 1 pc in length. The IRAS 21007+4951 outflow has carved a large cavity in the cloud through which background stars can be seen. Also, we have found an optical shock which is the counterflow to the previously discovered ''northwest outflow'' from LkHα 324SE

CLOUD PARAMETERIZATIONS, CLOUD PHYSICS, AND THEIR CONNECTIONS: AN OVERVIEW

International Nuclear Information System (INIS)

LIU, Y.; DAUM, P.H.; CHAI, S.K.; LIU, F.

2002-01-01

This paper consists of three parts. The first part is concerned with the parameterization of cloud microphysics in climate models. We demonstrate the crucial importance of spectral dispersion of the cloud droplet size distribution in determining radiative properties of clouds (e.g., effective radius), and underline the necessity of specifying spectral dispersion in the parameterization of cloud microphysics. It is argued that the inclusion of spectral dispersion makes the issue of cloud parameterization essentially equivalent to that of the droplet size distribution function, bringing cloud parameterization to the forefront of cloud physics. The second part is concerned with theoretical investigations into the spectral shape of droplet size distributions in cloud physics. After briefly reviewing the mainstream theories (including entrainment and mixing theories, and stochastic theories), we discuss their deficiencies and the need for a paradigm shift from reductionist approaches to systems approaches. A systems theory that has recently been formulated by utilizing ideas from statistical physics and information theory is discussed, along with the major results derived from it. It is shown that the systems formalism not only easily explains many puzzles that have been frustrating the mainstream theories, but also reveals such new phenomena as scale-dependence of cloud droplet size distributions. The third part is concerned with the potential applications of the systems theory to the specification of spectral dispersion in terms of predictable variables and scale-dependence under different fluctuating environments

A Highly Scalable Data Service (HSDS) using Cloud-based Storage Technologies for Earth Science Data

Science.gov (United States)

Michaelis, A.; Readey, J.; Votava, P.; Henderson, J.; Willmore, F.

2017-12-01

Cloud based infrastructure may offer several key benefits of scalability, built in redundancy, security mechanisms and reduced total cost of ownership as compared with a traditional data center approach. However, most of the tools and legacy software systems developed for online data repositories within the federal government were not developed with a cloud based infrastructure in mind and do not fully take advantage of commonly available cloud-based technologies. Moreover, services bases on object storage are well established and provided through all the leading cloud service providers (Amazon Web Service, Microsoft Azure, Google Cloud, etc…) of which can often provide unmatched "scale-out" capabilities and data availability to a large and growing consumer base at a price point unachievable from in-house solutions. We describe a system that utilizes object storage rather than traditional file system based storage to vend earth science data. The system described is not only cost effective, but shows a performance advantage for running many different analytics tasks in the cloud. To enable compatibility with existing tools and applications, we outline client libraries that are API compatible with existing libraries for HDF5 and NetCDF4. Performance of the system is demonstrated using clouds services running on Amazon Web Services.

Identification of the OGLE Blazars behind the Large and Small Magellanic Clouds

Directory of Open Access Journals (Sweden)

Natalia Żywucka

2017-11-01

Full Text Available We report the selection of blazar candidates behind the Large and Small Magellanic Clouds. Both flat spectrum radio quasar and BL Lacreate objects were selected based on the long-term, multi-colour Optical Gravitational Lensing Experiment photometric data. We cross-correlated the Magellanic Quasar Survey catalogue of spectroscopically confirmed quasars and quasar candidates located behind the Magellanic Clouds with the radio data at six frequencies from 0.8 to 20 GHz. Among the 1654 objects visible in optical range, we identified a sample of 44 newly selected blazar candidates, including 27 flat spectrum radio quasars and 17 BL Lacs. We examined selected objects with respect to their radio, optical, and mid-infrared properties.

Secure cloud computing

CERN Document Server

Jajodia, Sushil; Samarati, Pierangela; Singhal, Anoop; Swarup, Vipin; Wang, Cliff

2014-01-01

This book presents a range of cloud computing security challenges and promising solution paths. The first two chapters focus on practical considerations of cloud computing. In Chapter 1, Chandramouli, Iorga, and Chokani describe the evolution of cloud computing and the current state of practice, followed by the challenges of cryptographic key management in the cloud. In Chapter 2, Chen and Sion present a dollar cost model of cloud computing and explore the economic viability of cloud computing with and without security mechanisms involving cryptographic mechanisms. The next two chapters addres

Developing a Novel USB-PLC Controller for a Mechatronics Cloud Laboratory

Directory of Open Access Journals (Sweden)

Wen-Jye Shyr

2013-04-01

Full Text Available This study proposes the development and implementation of a novel Universal Serial Bus (USB-Programmable Logic Controller (PLC, called a USB-PLC controller, for a mechatronics cloud laboratory. The aim of a mechatronics cloud laboratory is to provide state of the art research quality equipment to students, allowing them to conduct hands-on experiments via the Internet. One objective of the cloud laboratory is to not only provide equipment for conducting set experiments, but also to provide a means for students to access research equipment in order to conduct individual research experiments. The proposed controller for these cloud laboratory experiments has been chosen in order to expose the students to as many different engineering and technology disciplines as possible.

Observation of the activity of selected Oort Cloud comets with perihelia at large distances from the Sun

Science.gov (United States)

Kulyk, Iryna; Rousselot, Philippe; Korsun, Pavlo

2016-10-01

Many comets exhibit considerable level of activity at large distances from the Sun, where sublimation of crystalline water ice cannot account for observable comae. Different patterns of physical activity already observed at large heliocentric distances may be related to the primordial differences in the composition of comet nuclei. Therefore, monitoring of physical activity in the wide range of heliocentric distances can potentially contribute to understanding of internal structure of comet-like bodies. We have observed ten long periodic comets with orbital perihelia lying beyond the "water ice sublimation zone" to quantify the level of physical activity in the wide range of heliocentric distances. Pre-perihelion observations were made when targets moved between 16.7 and 6.5 au from the Sun; post perihelion activity was monitored between 5.2 and 10.6 au. The bulk of the data were gathered with the 2-m Robotic Liverpool Telescope (Observatorio del Roque de Los Muchachos, La Palma, Spain). Some targets were observed with the 2-m RC Telescope located at Peak Terskol Observatory and the 6-m Telescope of the Special Astrophysical Observatory (Northern Caucasus, Russia). Since most of recently obtained spectra of distant active objects are continuum dominated, we use B, V, R images to estimate dust production rates, an upper limit on nucleus radii, and color indices of near nucleus region. The comets C/2005 L3 (McNaught) and C/2006 S3 (Boattini), which exhibit the considerable level of activity, have been repeatedly observed. This enables us to infer the heliocentric dependence of dust production rates, perihelion brightness asymmetries, and color variations over the comae caused possibly by small changes in dust particle properties.

Comparison of Cloud Properties from CALIPSO-CloudSat and Geostationary Satellite Data

Science.gov (United States)

Nguyen, L.; Minnis, P.; Chang, F.; Winker, D.; Sun-Mack, S.; Spangenberg, D.; Austin, R.

2007-01-01

Cloud properties are being derived in near-real time from geostationary satellite imager data for a variety of weather and climate applications and research. Assessment of the uncertainties in each of the derived cloud parameters is essential for confident use of the products. Determination of cloud amount, cloud top height, and cloud layering is especially important for using these real -time products for applications such as aircraft icing condition diagnosis and numerical weather prediction model assimilation. Furthermore, the distribution of clouds as a function of altitude has become a central component of efforts to evaluate climate model cloud simulations. Validation of those parameters has been difficult except over limited areas where ground-based active sensors, such as cloud radars or lidars, have been available on a regular basis. Retrievals of cloud properties are sensitive to the surface background, time of day, and the clouds themselves. Thus, it is essential to assess the geostationary satellite retrievals over a variety of locations. The availability of cloud radar data from CloudSat and lidar data from CALIPSO make it possible to perform those assessments over each geostationary domain at 0130 and 1330 LT. In this paper, CloudSat and CALIPSO data are matched with contemporaneous Geostationary Operational Environmental Satellite (GOES), Multi-functional Transport Satellite (MTSAT), and Meteosat-8 data. Unlike comparisons with cloud products derived from A-Train imagers, this study considers comparisons of nadir active sensor data with off-nadir retrievals. These matched data are used to determine the uncertainties in cloud-top heights and cloud amounts derived from the geostationary satellite data using the Clouds and the Earth s Radiant Energy System (CERES) cloud retrieval algorithms. The CERES multi-layer cloud detection method is also evaluated to determine its accuracy and limitations in the off-nadir mode. The results will be useful for

Role of orbital dynamics and cloud-cloud collisions in the formation of giant molecular clouds in global spiral structures

International Nuclear Information System (INIS)

Roberts, W.W. Jr.; Stewart, G.R.

1987-01-01

The role of orbit crowding and cloud-cloud collisions in the formation of GMCs and their organization in global spiral structure is investigated. Both N-body simulations of the cloud system and a detailed analysis of individual particle orbits are used to develop a conceptual understanding of how individual clouds participate in the collective density response. Detailed comparisons are made between a representative cloud-particle simulation in which the cloud particles collide inelastically with one another and give birth to and subsequently interact with young star associations and stripped down simulations in which the cloud particles are allowed to follow ballistic orbits in the absence of cloud-cloud collisions or any star formation processes. Orbit crowding is then related to the behavior of individual particle trajectories in the galactic potential field. The conceptual picture of how GMCs are formed in the clumpy ISMs of spiral galaxies is formulated, and the results are compared in detail with those published by other authors. 68 references

Dust and gas distribution in molecular clouds: an observational approach

International Nuclear Information System (INIS)

Campeggio, Loretta; Elia, Davide; Maiolo, Berlinda M T; Strafella, Francesco; Cecchi-Pestellini, Cesare

2005-01-01

The interstellar medium (ISM), gas and dust, appears to be arranged in clouds, whose dimensions, masses and densities span a large range of scales: from giant molecular clouds to small isolated globules. The structure of these objects show a high degree of complexity appearing, in the range of the observed scales, as a non-homogeneous ('clumpy') distribution of matter. The arrangement of the ISM is clearly relevant for the study of the fragmentation of the clouds and then of the star formation processes. To quantify observationally the ISM structure, many methods have been developed and our study is focused on some of them, exploiting multiwavelength observations of IS objects. The investigations presented here have been carried out by considering both the dust absorption (in optical and near IR wavelengths) and the gas emission (in the submm-radio spectral range). We present the maps obtained from the reduction of raw data and a first tentative analysis by means of methods as the structure function, the autocorrelation, and the Δ-variance. These are appropriate tools to highlight the complex structure of the ISM with reference to the paradigm given by the supersonic turbulence. Three observational cases are briefly discussed. In order to analyse the structure of objects characterized by different sizes, we applied the above-mentioned algorithms to the extinction map of the dark globule CB 107 and to the CO(J = 1-0) integrated intensity map of Vela Molecular Ridge, D Cloud. Finally we compare the results obtained with synthetic fractal maps known as 'fractional Brownian motion' fBm images

CLOUD COMPUTING SECURITY

Directory of Open Access Journals (Sweden)

Ştefan IOVAN

2016-05-01

Full Text Available Cloud computing reprentes the software applications offered as a service online, but also the software and hardware components from the data center.In the case of wide offerd services for any type of client, we are dealing with a public cloud. In the other case, in wich a cloud is exclusively available for an organization and is not available to the open public, this is consider a private cloud [1]. There is also a third type, called hibrid in which case an user or an organization might use both services available in the public and private cloud. One of the main challenges of cloud computing are to build the trust and ofer information privacy in every aspect of service offerd by cloud computingle. The variety of existing standards, just like the lack of clarity in sustenability certificationis not a real help in building trust. Also appear some questions marks regarding the efficiency of traditionsecurity means that are applied in the cloud domain. Beside the economic and technology advantages offered by cloud, also are some advantages in security area if the information is migrated to cloud. Shared resources available in cloud includes the survey, use of the "best practices" and technology for advance security level, above all the solutions offered by the majority of medium and small businesses, big companies and even some guvermental organizations [2].

Size-density relations in dark clouds: Non-LTE effects

Science.gov (United States)

Maloney, P.

1986-01-01

One of the major goals of molecular astronomy has been to understand the physics and dynamics of dense interstellar clouds. Because the interpretation of observations of giant molecular clouds is complicated by their very complex structure and the dynamical effects of star formation, a number of studies have concentrated on dark clouds. Leung, Kutner and Mead (1982) (hereafter LKM) and Myers (1983), in studies of CO and NH3 emission, concluded that dark clouds exhibit significant correlations between linewidth and cloud radius of the form delta v varies as R(0.5) and between mean density and radius of the form n varies as R(-1), as originally suggested by Larson (1981). This result suggests that these objects are in virial equilibrium. However, the mean densities inferred from the CO data of LKM are based on an local thermodynamic equilibrium (LTE) analysis of their 13CO data. At the very low mean densities inferred by LKM for the larger clouds in their samples, the assumption of LTE becomes very questionable. As most of the range in R in the density-size correlation comes from the clouds observed in CO, it seems worthwhile to examine how non-LTE effects will influence the derived densities. One way to assess the validity of LTE-derived densities is to construct cloud models and then to interpret them in the same way as the observed data. Microturbulent models of inhomogeneous clouds of varying central concentration with the linewidth-size and mean density-size relations found by Myers show sub-thermal excitation of the 13CO line in the larger clouds, with the result that LTE analysis considerbly underestimates the actual column density. A more general approach which doesn't require detailed modeling of the clouds is to consider whether the observed T sub R*(13CO)/T sub R*(12CO) ratios in the clouds studied by LKM are in the range where the LTE-derived optical depths (and hence column densities) can be seriously in error due to sub-thermal excitation of the 13CO

THE INFLUENCE OF NONUNIFORM CLOUD COVER ON TRANSIT TRANSMISSION SPECTRA

Energy Technology Data Exchange (ETDEWEB)

Line, Michael R. [NASA Ames Research Center, Moffet Field, CA 94035 (United States); Parmentier, Vivien, E-mail: mrline@ucsc.edu [Department of Astronomy and Astrophysics, University of California–Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)

2016-03-20

We model the impact of nonuniform cloud cover on transit transmission spectra. Patchy clouds exist in nearly every solar system atmosphere, brown dwarfs, and transiting exoplanets. Our major findings suggest that fractional cloud coverage can exactly mimic high mean molecular weight atmospheres and vice versa over certain wavelength regions, in particular, over the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) bandpass (1.1–1.7 μm). We also find that patchy cloud coverage exhibits a signature that is different from uniform global clouds. Furthermore, we explain analytically why the “patchy cloud-high mean molecular weight” degeneracy exists. We also explore the degeneracy of nonuniform cloud coverage in atmospheric retrievals on both synthetic and real planets. We find from retrievals on a synthetic solar composition hot Jupiter with patchy clouds and a cloud-free high mean molecular weight warm Neptune that both cloud-free high mean molecular weight atmospheres and partially cloudy atmospheres can explain the data equally well. Another key finding is that the HST WFC3 transit transmission spectra of two well-observed objects, the hot Jupiter HD 189733b and the warm Neptune HAT-P-11b, can be explained well by solar composition atmospheres with patchy clouds without the need to invoke high mean molecular weight or global clouds. The degeneracy between high molecular weight and solar composition partially cloudy atmospheres can be broken by observing the molecular Rayleigh scattering differences between the two. Furthermore, the signature of partially cloudy limbs also appears as a ∼100 ppm residual in the ingress and egress of the transit light curves, provided that the transit timing is known to seconds.

Evolutionary Multiobjective Query Workload Optimization of Cloud Data Warehouses

Science.gov (United States)

Dokeroglu, Tansel; Sert, Seyyit Alper; Cinar, Muhammet Serkan

2014-01-01

With the advent of Cloud databases, query optimizers need to find paretooptimal solutions in terms of response time and monetary cost. Our novel approach minimizes both objectives by deploying alternative virtual resources and query plans making use of the virtual resource elasticity of the Cloud. We propose an exact multiobjective branch-and-bound and a robust multiobjective genetic algorithm for the optimization of distributed data warehouse query workloads on the Cloud. In order to investigate the effectiveness of our approach, we incorporate the devised algorithms into a prototype system. Finally, through several experiments that we have conducted with different workloads and virtual resource configurations, we conclude remarkable findings of alternative deployments as well as the advantages and disadvantages of the multiobjective algorithms we propose. PMID:24892048

Cloud Collaboration: Cloud-Based Instruction for Business Writing Class

Science.gov (United States)

Lin, Charlie; Yu, Wei-Chieh Wayne; Wang, Jenny

2014-01-01

Cloud computing technologies, such as Google Docs, Adobe Creative Cloud, Dropbox, and Microsoft Windows Live, have become increasingly appreciated to the next generation digital learning tools. Cloud computing technologies encourage students' active engagement, collaboration, and participation in their learning, facilitate group work, and support…

The Role of Emissivity in the Detection of Arctic Night Clouds

Directory of Open Access Journals (Sweden)

Filomena Romano

2017-04-01

Full Text Available Detection of clouds over polar areas from satellite radiometric measurements in the visible and IR atmospheric window region is rather difficult because of the high albedo of snow, possible ice covered surfaces, very low humidity, and the usual presence of atmospheric temperature inversion. Cold and highly reflective polar surfaces provide little thermal and visible contrast between clouds and the background surface. Moreover, due to the presence of temperature inversion, clouds are not always identifiable as being colder than the background. In addition, low humidity often causes polar clouds to be optically thin. Finally, polar clouds are usually composed of a mixture of ice and water, which leads to an unclear spectral signature. Single and bi-spectral threshold methods are sometimes inappropriate due to a large variability of surface emissivity and cloud conditions. The objective of this study is to demonstrate the crucial role played by surface emissivity in the detection of polar winter clouds and the potential improvement offered by infrared hyperspectral observations, such as from the Infrared Atmospheric Sounding Interferometer (IASI. In this paper a new approach for cloud detection is proposed and validated exploiting active measurements from satellite sensors, i.e., the CloudSat cloud profiling radar (CPR and the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO. For a homogenous IASI field of view (FOVs, the proposed cloud detection scheme tallies with the combined CPR and CALIOP product in classifying 98.11% of the FOVs as cloudy and also classifies 97.54% of the FOVs as clear. The Hansen Kuipers discriminant reaches 0.95.

The Cloud-Aerosol Transport System (CATS): A New Lidar for Aerosol and Cloud Profiling from the International Space Station

Science.gov (United States)

Welton, Ellsworth J.; McGill, Mathew J.; Yorks. John E.; Hlavka, Dennis L.; Hart, William D.; Palm, Stephen P.; Colarco, Peter R.

2012-01-01

Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064,532,355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time (NRT) data capability ofthe ISS will enable CATS to support operational applications such as aerosol and air quality forecasting and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a

Fast grasping of unknown objects using principal component analysis

Science.gov (United States)

Lei, Qujiang; Chen, Guangming; Wisse, Martijn

2017-09-01

Fast grasping of unknown objects has crucial impact on the efficiency of robot manipulation especially subjected to unfamiliar environments. In order to accelerate grasping speed of unknown objects, principal component analysis is utilized to direct the grasping process. In particular, a single-view partial point cloud is constructed and grasp candidates are allocated along the principal axis. Force balance optimization is employed to analyze possible graspable areas. The obtained graspable area with the minimal resultant force is the best zone for the final grasping execution. It is shown that an unknown object can be more quickly grasped provided that the component analysis principle axis is determined using single-view partial point cloud. To cope with the grasp uncertainty, robot motion is assisted to obtain a new viewpoint. Virtual exploration and experimental tests are carried out to verify this fast gasping algorithm. Both simulation and experimental tests demonstrated excellent performances based on the results of grasping a series of unknown objects. To minimize the grasping uncertainty, the merits of the robot hardware with two 3D cameras can be utilized to suffice the partial point cloud. As a result of utilizing the robot hardware, the grasping reliance is highly enhanced. Therefore, this research demonstrates practical significance for increasing grasping speed and thus increasing robot efficiency under unpredictable environments.

Comparison Between CCCM and CloudSat Radar-Lidar (RL) Cloud and Radiation Products

Science.gov (United States)

Ham, Seung-Hee; Kato, Seiji; Rose, Fred G.; Sun-Mack, Sunny

2015-01-01

To enhance cloud properties, LaRC and CIRA developed each combination algorithm for obtained properties from passive, active and imager in A-satellite constellation. When comparing global cloud fraction each other, LaRC-produced CERES-CALIPSO-CloudSat-MODIS (CCCM) products larger low-level cloud fraction over tropic ocean, while CIRA-produced Radar-Lidar (RL) shows larger mid-level cloud fraction for high latitude region. The reason for different low-level cloud fraction is due to different filtering method of lidar-detected cloud layers. Meanwhile difference in mid-level clouds is occurred due to different priority of cloud boundaries from lidar and radar.

Continuous growth of cloud droplets in cumulus cloud

International Nuclear Information System (INIS)

Gotoh, Toshiyuki; Suehiro, Tamotsu; Saito, Izumi

2016-01-01

A new method to seamlessly simulate the continuous growth of droplets advected by turbulent flow inside a cumulus cloud was developed from first principle. A cubic box ascending with a mean updraft inside a cumulus cloud was introduced and the updraft velocity was self-consistently determined in such a way that the mean turbulent velocity within the box vanished. All the degrees of freedom of the cloud droplets and turbulence fields were numerically integrated. The box ascended quickly inside the cumulus cloud due to the updraft and the mean radius of the droplets grew from 10 to 24 μ m for about 10 min. The turbulent flow tended to slow down the time evolutions of the updraft velocity, the box altitude and the mean cloud droplet radius. The size distribution of the cloud droplets in the updraft case was narrower than in the absence of the updraft. It was also found that the wavenumeber spectra of the variances of the temperature and water vapor mixing ratio were nearly constant in the low wavenumber range. The future development of the new method was argued. (paper)

OPTICAL AND NEAR-INFRARED SHOCKS IN THE L988 CLOUD COMPLEX

Energy Technology Data Exchange (ETDEWEB)

Walawender, J. [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Reipurth, B. [Institute for Astronomy, University of Hawaii at Manoa, Hilo, HI 96720 (United States); Bally, J., E-mail: joshw@naoj.org [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States)

2013-09-15

We have searched the Lynds 988 dark cloud complex for optical (H{alpha} and [S II]) and near-IR (H{sub 2} 2.12 {mu}m) shocks from protostellar outflows. We find 20 new Herbig-Haro objects and 6 new H{sub 2} shocks (MHO objects), 3 of which are cross detections. Using the morphology in the optical and near-IR, we connect several of these shocks into at least five distinct outflow systems and identify their source protostars from catalogs of infrared sources. Two outflows in the cloud, from IRAS 21014+5001 and IRAS 21007+4951, are in excess of 1 pc in length. The IRAS 21007+4951 outflow has carved a large cavity in the cloud through which background stars can be seen. Also, we have found an optical shock which is the counterflow to the previously discovered ''northwest outflow'' from LkH{alpha} 324SE.

Hidden in the Clouds: New Ideas in Cloud Computing

CERN Multimedia

CERN. Geneva

2013-01-01

Abstract: Cloud computing has become a hot topic. But 'cloud' is no newer in 2013 than MapReduce was in 2005: We've been doing both for years. So why is cloud more relevant today than it ever has been? In this presentation, we will introduce the (current) central thesis of cloud computing, and explore how and why (or even whether) the concept has evolved. While we will cover a little light background, our primary focus will be on the consequences, corollaries and techniques introduced by some of the leading cloud developers and organizations. We each have a different deployment model, different applications and workloads, and many of us are still learning to efficiently exploit the platform services offered by a modern implementation. The discussion will offer the opportunity to share these experiences and help us all to realize the benefits of cloud computing to the fullest degree. Please bring questions and opinions, and be ready to share both!   Bio: S...

Cloud Computing

CERN Document Server

Antonopoulos, Nick

2010-01-01

Cloud computing has recently emerged as a subject of substantial industrial and academic interest, though its meaning and scope is hotly debated. For some researchers, clouds are a natural evolution towards the full commercialisation of grid systems, while others dismiss the term as a mere re-branding of existing pay-per-use technologies. From either perspective, 'cloud' is now the label of choice for accountable pay-per-use access to third party applications and computational resources on a massive scale. Clouds support patterns of less predictable resource use for applications and services a

Study into Point Cloud Geometric Rigidity and Accuracy of TLS-Based Identification of Geometric Bodies

Science.gov (United States)

Klapa, Przemyslaw; Mitka, Bartosz; Zygmunt, Mariusz

2017-12-01

Capability of obtaining a multimillion point cloud in a very short time has made the Terrestrial Laser Scanning (TLS) a widely used tool in many fields of science and technology. The TLS accuracy matches traditional devices used in land surveying (tacheometry, GNSS - RTK), but like any measurement it is burdened with error which affects the precise identification of objects based on their image in the form of a point cloud. The point’s coordinates are determined indirectly by means of measuring the angles and calculating the time of travel of the electromagnetic wave. Each such component has a measurement error which is translated into the final result. The XYZ coordinates of a measuring point are determined with some uncertainty and the very accuracy of determining these coordinates is reduced as the distance to the instrument increases. The paper presents the results of examination of geometrical stability of a point cloud obtained by means terrestrial laser scanner and accuracy evaluation of solids determined using the cloud. Leica P40 scanner and two different settings of measuring points were used in the tests. The first concept involved placing a few balls in the field and then scanning them from various sides at similar distances. The second part of measurement involved placing balls and scanning them a few times from one side but at varying distances from the instrument to the object. Each measurement encompassed a scan of the object with automatic determination of its position and geometry. The desk studies involved a semiautomatic fitting of solids and measurement of their geometrical elements, and comparison of parameters that determine their geometry and location in space. The differences of measures of geometrical elements of balls and translations vectors of the solids centres indicate the geometrical changes of the point cloud depending on the scanning distance and parameters. The results indicate the changes in the geometry of scanned objects

The CLOUD experiment

CERN Multimedia

Maximilien Brice

2006-01-01

The Cosmics Leaving Outdoor Droplets (CLOUD) experiment as shown by Jasper Kirkby (spokesperson). Kirkby shows a sketch to illustrate the possible link between galactic cosmic rays and cloud formations. The CLOUD experiment uses beams from the PS accelerator at CERN to simulate the effect of cosmic rays on cloud formations in the Earth's atmosphere. It is thought that cosmic ray intensity is linked to the amount of low cloud cover due to the formation of aerosols, which induce condensation.

Clouds of Venus

Energy Technology Data Exchange (ETDEWEB)

Knollenberg, R G [Particle Measuring Systems, Inc., 1855 South 57th Court, Boulder, Colorado 80301, U.S.A.; Hansen, J [National Aeronautics and Space Administration, New York (USA). Goddard Inst. for Space Studies; Ragent, B [National Aeronautics and Space Administration, Moffett Field, Calif. (USA). Ames Research Center; Martonchik, J [Jet Propulsion Lab., Pasadena, Calif. (USA); Tomasko, M [Arizona Univ., Tucson (USA)

1977-05-01

The current state of knowledge of the Venusian clouds is reviewed. The visible clouds of Venus are shown to be quite similar to low level terrestrial hazes of strong anthropogenic influence. Possible nucleation and particle growth mechanisms are presented. The Pioneer Venus experiments that emphasize cloud measurements are described and their expected findings are discussed in detail. The results of these experiments should define the cloud particle composition, microphysics, thermal and radiative heat budget, rough dynamical features and horizontal and vertical variations in these and other parameters. This information should be sufficient to initialize cloud models which can be used to explain the cloud formation, decay, and particle life cycle.

ASTER cloud coverage reassessment using MODIS cloud mask products

Science.gov (United States)

Tonooka, Hideyuki; Omagari, Kunjuro; Yamamoto, Hirokazu; Tachikawa, Tetsushi; Fujita, Masaru; Paitaer, Zaoreguli

2010-10-01

In the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) Project, two kinds of algorithms are used for cloud assessment in Level-1 processing. The first algorithm based on the LANDSAT-5 TM Automatic Cloud Cover Assessment (ACCA) algorithm is used for a part of daytime scenes observed with only VNIR bands and all nighttime scenes, and the second algorithm based on the LANDSAT-7 ETM+ ACCA algorithm is used for most of daytime scenes observed with all spectral bands. However, the first algorithm does not work well for lack of some spectral bands sensitive to cloud detection, and the two algorithms have been less accurate over snow/ice covered areas since April 2008 when the SWIR subsystem developed troubles. In addition, they perform less well for some combinations of surface type and sun elevation angle. We, therefore, have developed the ASTER cloud coverage reassessment system using MODIS cloud mask (MOD35) products, and have reassessed cloud coverage for all ASTER archived scenes (>1.7 million scenes). All of the new cloud coverage data are included in Image Management System (IMS) databases of the ASTER Ground Data System (GDS) and NASA's Land Process Data Active Archive Center (LP DAAC) and used for ASTER product search by users, and cloud mask images are distributed to users through Internet. Daily upcoming scenes (about 400 scenes per day) are reassessed and inserted into the IMS databases in 5 to 7 days after each scene observation date. Some validation studies for the new cloud coverage data and some mission-related analyses using those data are also demonstrated in the present paper.

Moving HammerCloud to CERN's private cloud

CERN Document Server

Barrand, Quentin

2013-01-01

HammerCloud is a testing framework for the Worldwide LHC Computing Grid. Currently deployed on about 20 hand-managed machines, it was desirable to move it to the Agile Infrastructure, CERN's OpenStack-based private cloud.

Galalctic Tides & the Sinusoidal Potential

Science.gov (United States)

Bartlett, David F.

2011-05-01

The sinusoidal potential is a nonNewtonian alternative to dark matter. Instead of φ = -GM/r we write φ = -(GM/r) cos kor, where ko= 2π/ λo and λo = Ro/20= 400 pc. Evidence for this choice for the "wavelength” λo has been given in one article and many previous meetings of the AAS & DDA. The solar system and nearby stars are trapped in a local groove of width Δr Quality (4 types) and semi-major axis aoriginal . For 10 of the 12 classes radial tides dominate Z-tides. The classic Oort cloud comets (1851-1996) have a particularly strong modulation with galactic longitude. This modulation is exactly in those directions where a radial tide would be important. The equally numerous recent Oort comets (1996-2008) show a different evidence for strong radial tides. The recent comets generally have much larger perihelion distances q than the classic ones. Here the evidence is that a radial tide is removing angular momentum from the orbit and thus bringing the perihelion closer to the earth and to observers.

Cloud Robotics Platforms

Directory of Open Access Journals (Sweden)

Busra Koken

2015-01-01

Full Text Available Cloud robotics is a rapidly evolving field that allows robots to offload computation-intensive and storage-intensive jobs into the cloud. Robots are limited in terms of computational capacity, memory and storage. Cloud provides unlimited computation power, memory, storage and especially collaboration opportunity. Cloud-enabled robots are divided into two categories as standalone and networked robots. This article surveys cloud robotic platforms, standalone and networked robotic works such as grasping, simultaneous localization and mapping (SLAM and monitoring.

Cloud ERP and Cloud Accounting Software in Romania

Directory of Open Access Journals (Sweden)

Gianina MIHAI

2015-05-01

Full Text Available Nowadays, Cloud Computing becomes a more and more fashionable concept in the IT environment. There is no unanimous opinion on the definition of this concept, as it covers several versions of the newly emerged stage in the IT. But in fact, Cloud Computing should not suggest anything else than simplicity. Thus, in short, simple terms, Cloud Computing can be defined as a solution to use external IT resources (servers, storage media, applications and services, via Internet. Cloud computing is nothing more than the promise of an easy accessible technology. If the promise will eventually turn into something certain yet remains to be seen. In our opinion it is too early to make an assertion. In this article, our purpose is to find out what is the Romanian offer of ERP and Accounting software applications in Cloud and / or as services in SaaS version. Thus, we conducted an extensive study whose results we’ll present in the following.

Security prospects through cloud computing by adopting multiple clouds

DEFF Research Database (Denmark)

Jensen, Meiko; Schwenk, Jörg; Bohli, Jens Matthias

2011-01-01

Clouds impose new security challenges, which are amongst the biggest obstacles when considering the usage of cloud services. This triggered a lot of research activities in this direction, resulting in a quantity of proposals targeting the various security threats. Besides the security issues coming...... with the cloud paradigm, it can also provide a new set of unique features which open the path towards novel security approaches, techniques and architectures. This paper initiates this discussion by contributing a concept which achieves security merits by making use of multiple distinct clouds at the same time....

Radiative properties of clouds

International Nuclear Information System (INIS)

Twomey, S.

1993-01-01

The climatic effects of condensation nuclei in the formation of cloud droplets and the subsequent role of the cloud droplets as contributors to the planetary short-wave albedo is emphasized. Microphysical properties of clouds, which can be greatly modified by the degree of mixing with cloud-free air from outside, are discussed. The effect of clouds on visible radiation is assessed through multiple scattering of the radiation. Cloudwater or ice absorbs more with increasing wavelength in the near-infrared region, with water vapor providing the stronger absorption over narrower wavelength bands. Cloud thermal infrared absorption can be solely related to liquid water content at least for shallow clouds and clouds in the early development state. Three-dimensional general circulation models have been used to study the climatic effect of clouds. It was found for such studies (which did not consider variations in cloud albedo) that the cooling effects due to the increase in planetary short-wave albedo from clouds were offset by heating effects due to thermal infrared absorption by the cloud. Two permanent direct effects of increased pollution are discussed in this chapter: (a) an increase of absorption in the visible and near infrared because of increased amounts of elemental carbon, which gives rise to a warming effect climatically, and (b) an increased optical thickness of clouds due to increasing cloud droplet number concentration caused by increasing cloud condensation nuclei number concentration, which gives rise to a cooling effect climatically. An increase in cloud albedo from 0.7 to 0.87 produces an appreciable climatic perturbation of cooling up to 2.5 K at the ground, using a hemispheric general circulation model. Effects of pollution on cloud thermal infrared absorption are negligible

The Spitzer survey of interstellar clouds in the gould belt. VI. The Auriga-California molecular cloud observed with IRAC and MIPS

International Nuclear Information System (INIS)

Broekhoven-Fiene, Hannah; Matthews, Brenda C.; Harvey, Paul M.; Gutermuth, Robert A.; Huard, Tracy L.; Miller, Jennifer F.; Tothill, Nicholas F. H.; Nutter, David; Bourke, Tyler L.; DiFrancesco, James; Jørgensen, Jes K.; Allen, Lori E.; Chapman, Nicholas L.; Dunham, Michael M.; Merín, Bruno; Terebey, Susan; Peterson, Dawn E.

2014-01-01

We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg 2 with IRAC and 10.47 deg 2 with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors, and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkHα 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the relative fraction of YSOs in earlier (Class I and F) and later (Class II) classes compared to other clouds. We perform simple SED modeling of the YSOs with disks to compare the mid-IR properties to disks in other clouds and identify 14 classical transition disk candidates. Although the AMC is similar in mass, size, and distance to the OMC, it is forming about 15-20 times fewer stars.

The Spitzer survey of interstellar clouds in the gould belt. VI. The Auriga-California molecular cloud observed with IRAC and MIPS

Energy Technology Data Exchange (ETDEWEB)

Broekhoven-Fiene, Hannah; Matthews, Brenda C. [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6 (Canada); Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Huard, Tracy L.; Miller, Jennifer F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Tothill, Nicholas F. H. [School of Computing, Engineering and Mathematics, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751 (Australia); Nutter, David [School of Physics and Astronomy, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); DiFrancesco, James [National Research Council Herzberg Astronomy and Astrophysics, Victoria, BC, V9E 2E7 (Canada); Jørgensen, Jes K. [Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-DK-2100 Copenhagen Ø. (Denmark); Allen, Lori E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Chapman, Nicholas L. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Dunham, Michael M. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Merín, Bruno [Herschel Science Centre, ESAC-ESA, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Terebey, Susan [Department of Physics and Astronomy PS315, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Peterson, Dawn E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); and others

2014-05-01

We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg{sup 2} with IRAC and 10.47 deg{sup 2} with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors, and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude and color-color diagrams, we find evidence for a substantial population of 166 young stellar objects (YSOs) in the cloud, many of which were previously unknown. Most of this population is concentrated around the LkHα 101 cluster and the filament extending from it. We present a quantitative description of the degree of clustering and discuss the relative fraction of YSOs in earlier (Class I and F) and later (Class II) classes compared to other clouds. We perform simple SED modeling of the YSOs with disks to compare the mid-IR properties to disks in other clouds and identify 14 classical transition disk candidates. Although the AMC is similar in mass, size, and distance to the OMC, it is forming about 15-20 times fewer stars.

CLOUD STORAGE SERVICES

OpenAIRE

Yan, Cheng

2017-01-01

Cloud computing is a hot topic in recent research and applications. Because it is widely used in various fields. Up to now, Google, Microsoft, IBM, Amazon and other famous co partnership have proposed their cloud computing application. Look upon cloud computing as one of the most important strategy in the future. Cloud storage is the lower layer of cloud computing system which supports the service of the other layers above it. At the same time, it is an effective way to store and manage heavy...

CloudSat observations of cloud-type distribution over the Indian summer monsoon region

Directory of Open Access Journals (Sweden)

K. V. Subrahmanyam

2013-07-01

Full Text Available The three-dimensional distribution of various cloud types over the Indian summer monsoon (ISM region using five years (2006–2010 of CloudSat observations during June-July-August-September months is discussed for the first time. As the radiative properties, latent heat released and microphysical properties of clouds differ largely depending on the cloud type, it becomes important to know what types of clouds occur over which region. In this regard, the present analysis establishes the three-dimensional distribution of frequency of occurrence of stratus (St, stratocumulus (Sc, nimbostratus (Ns, cumulus (Cu, altocumulus (Ac, altostratus (As, cirrus (Ci and deep convective (DC clouds over the ISM region. The results show that the various cloud types preferentially occur over some regions of the ISM, which are consistent during all the years of observations. It is found that the DC clouds frequently occur over northeast of Bay of Bengal (BoB, Ci clouds over a wide region of south BoB–Indian peninsula–equatorial Indian Ocean, and Sc clouds over the north Arabian Sea. Ac clouds preferentially occur over land, and a large amount of As clouds are found over BoB. The occurrence of both St and Ns clouds over the study region is much lower than all other cloud types.The interannual variability of all these clouds including their vertical distribution is discussed. It is envisaged that the present study opens up possibilities to quantify the feedback of individual cloud type in the maintenance of the ISM through radiative forcing and latent heat release.

CONCEPTS AND CHARACTERISTICS OF CLOUD ORIENTED LEARNING ENVIRONMENT OF SCHOOL

Directory of Open Access Journals (Sweden)

Svitlana G. Lytvynova

2014-04-01

Full Text Available The article deals with the basic concepts and characteristics of cloud oriented learning environment (COLE of secondary school. It is examined the concept of "cloud oriented learning environment", "mobility training", the requirements for COLE, the goal of creating, the structural components, model deployment, maintenance. Four cloud storages are compared; the subjects and objects of COLE are described; the meaning of spatial and semantic, content and methodical, communication and organizational components are clarified; the benefits and features of cloud computing are defined. It is found that COLE creates conditions for active cooperation, provides mobility of learning process participants, and objects’ virtualization. It is available anywhere and at any time, ensures the development of creativity and innovation, critical thinking, ability to solve problems, to develop communicative, cooperative, life and career skills, to work with data, media, to develop ICT competence either of students and teachers.

CubeSat Constellation Cloud Winds(C3Winds) A New Wind Observing System to Study Mesoscale Cloud Dynamics and Processes

Science.gov (United States)

Wu, D. L.; Kelly, M.A.; Yee, J.-H.; Boldt, J.; Demajistre, R.; Reynolds, E. L.; Tripoli, G. J.; Oman, L. D.; Prive, N.; Heidinger, A. K.;

VMware vCloud security

CERN Document Server

Sarkar, Prasenjit

2013-01-01

VMware vCloud Security provides the reader with in depth knowledge and practical exercises sufficient to implement a secured private cloud using VMware vCloud Director and vCloud Networking and Security.This book is primarily for technical professionals with system administration and security administration skills with significant VMware vCloud experience who want to learn about advanced concepts of vCloud security and compliance.

Interstellar Extinction in the Direction of The Barnard 1 Dark Cloud in Perseus

Directory of Open Access Journals (Sweden)

Černis K.

2003-09-01

Full Text Available Spectral and luminosity classes, absolute magnitudes, color excesses, interstellar extinctions and distances are determined for 98 stars down to 18 mag in the Barnard 1 dark cloud belonging to the Per OB2 association. The classification of stars is based on their photoelectric photometry in the Vilnius seven-color photometric system. The extinction vs. distance diagram exhibits the presence of two dust layers at 150 and 230 pc distances. The distance of the first cloud, which gives an extinction Ay of 0.3 mag, coincides with the distance of the Taurus dark cloud complex. The second cloud with much larger extinction is about at the same distance as the clouds in the direction of the nearby objects: reflection nebula NGC 1333 and open cluster IG 348.

Three-dimensional reconstruction of indoor whole elements based on mobile LiDAR point cloud data

Science.gov (United States)

Gong, Yuejian; Mao, Wenbo; Bi, Jiantao; Ji, Wei; He, Zhanjun

2014-11-01

Ground-based LiDAR is one of the most effective city modeling tools at present, which has been widely used for three-dimensional reconstruction of outdoor objects. However, as for indoor objects, there are some technical bottlenecks due to lack of GPS signal. In this paper, based on the high-precision indoor point cloud data which was obtained by LiDAR, an international advanced indoor mobile measuring equipment, high -precision model was fulfilled for all indoor ancillary facilities. The point cloud data we employed also contain color feature, which is extracted by fusion with CCD images. Thus, it has both space geometric feature and spectral information which can be used for constructing objects' surface and restoring color and texture of the geometric model. Based on Autodesk CAD platform and with help of PointSence plug, three-dimensional reconstruction of indoor whole elements was realized. Specifically, Pointools Edit Pro was adopted to edit the point cloud, then different types of indoor point cloud data was processed, including data format conversion, outline extracting and texture mapping of the point cloud model. Finally, three-dimensional visualization of the real-world indoor was completed. Experiment results showed that high-precision 3D point cloud data obtained by indoor mobile measuring equipment can be used for indoor whole elements' 3-d reconstruction and that methods proposed in this paper can efficiently realize the 3 -d construction of indoor whole elements. Moreover, the modeling precision could be controlled within 5 cm, which was proved to be a satisfactory result.

Characterizing Water Ice Clouds on the Coldest Known Brown Dwarf

Science.gov (United States)

Luhman, Kevin; Burgasser, Adam; Cushing, Michael; Esplin, Taran; Fortney, Jonathan; Hardegree-Ullman, Kevin; Marley, Mark; Morley, Caroline; Schneider, Adam; Trucks, Jesica

2014-12-01

We have conducted a search for high proper motion brown dwarfs using multi-epoch all-sky mid-infrared images from the WISE satellite. Through this work, we have discovered an object with a parallactic distance of 2.3 pc and a temperature of 250 K, making it the 4th closest neighbor of the Sun, and the coldest known brown dwarf. Because of its extreme proximity and temperature, it represents an unparalleled laboratory for studying planet-like atmospheres in an unexplored temperature regime. We propose to photometrically monitor this object with IRAC to 1) detect and characterize water ice clouds in its atmosphere via the short-term variations induced during rotation and 2) constrain the long-term evolution of its clouds across a period of months.

Joint classification and contour extraction of large 3D point clouds

Science.gov (United States)

Hackel, Timo; Wegner, Jan D.; Schindler, Konrad

2017-08-01

We present an effective and efficient method for point-wise semantic classification and extraction of object contours of large-scale 3D point clouds. What makes point cloud interpretation challenging is the sheer size of several millions of points per scan and the non-grid, sparse, and uneven distribution of points. Standard image processing tools like texture filters, for example, cannot handle such data efficiently, which calls for dedicated point cloud labeling methods. It turns out that one of the major drivers for efficient computation and handling of strong variations in point density, is a careful formulation of per-point neighborhoods at multiple scales. This allows, both, to define an expressive feature set and to extract topologically meaningful object contours. Semantic classification and contour extraction are interlaced problems. Point-wise semantic classification enables extracting a meaningful candidate set of contour points while contours help generating a rich feature representation that benefits point-wise classification. These methods are tailored to have fast run time and small memory footprint for processing large-scale, unstructured, and inhomogeneous point clouds, while still achieving high classification accuracy. We evaluate our methods on the semantic3d.net benchmark for terrestrial laser scans with >109 points.

Cloud-Based RFID Mutual Authentication Protocol without Leaking Location Privacy to the Cloud

OpenAIRE

Dong, Qingkuan; Tong, Jiaqing; Chen, Yuan

2015-01-01

With the rapid developments of the IoT (Internet of Things) and the cloud computing, cloud-based RFID systems attract more attention. Users can reduce their cost of deploying and maintaining the RFID system by purchasing cloud services. However, the security threats of cloud-based RFID systems are more serious than those of traditional RFID systems. In cloud-based RFID systems, the connection between the reader and the cloud database is not secure and cloud service provider is not trusted. Th...

Cloud Computing Bible

CERN Document Server

Sosinsky, Barrie

2010-01-01

The complete reference guide to the hot technology of cloud computingIts potential for lowering IT costs makes cloud computing a major force for both IT vendors and users; it is expected to gain momentum rapidly with the launch of Office Web Apps later this year. Because cloud computing involves various technologies, protocols, platforms, and infrastructure elements, this comprehensive reference is just what you need if you'll be using or implementing cloud computing.Cloud computing offers significant cost savings by eliminating upfront expenses for hardware and software; its growing popularit

Integrated cloud-aerosol-radiation product using CERES, MODIS, CALIPSO, and CloudSat data

Science.gov (United States)

Sun-Mack, Sunny; Minnis, Patrick; Chen, Yan; Gibson, Sharon; Yi, Yuhong; Trepte, Qing; Wielicki, Bruce; Kato, Seiji; Winker, Dave; Stephens, Graeme; Partain, Philip

2007-10-01

This paper documents the development of the first integrated data set of global vertical profiles of clouds, aerosols, and radiation using the combined NASA A-Train data from the Aqua Clouds and Earth's Radiant Energy System (CERES) and Moderate Resolution Imaging Spectroradiometer (MODIS), Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and CloudSat. As part of this effort, cloud data from the CALIPSO lidar and the CloudSat radar are merged with the integrated column cloud properties from the CERES-MODIS analyses. The active and passive datasets are compared to determine commonalities and differences in order to facilitate the development of a 3-dimensional cloud and aerosol dataset that will then be integrated into the CERES broadband radiance footprint. Preliminary results from the comparisons for April 2007 reveal that the CERES-MODIS global cloud amounts are, on average, 0.14 less and 0.15 greater than those from CALIPSO and CloudSat, respectively. These new data will provide unprecedented ability to test and improve global cloud and aerosol models, to investigate aerosol direct and indirect radiative forcing, and to validate the accuracy of global aerosol, cloud, and radiation data sets especially in polar regions and for multi-layered cloud conditions.

IBM SmartCloud essentials

CERN Document Server

Schouten, Edwin

2013-01-01

A practical, user-friendly guide that provides an introduction to cloud computing using IBM SmartCloud, along with a thorough understanding of resource management in a cloud environment.This book is great for anyone who wants to get a grasp of what cloud computing is and what IBM SmartCloud has to offer. If you are an IT specialist, IT architect, system administrator, or a developer who wants to thoroughly understand the cloud computing resource model, this book is ideal for you. No prior knowledge of cloud computing is expected.

Photometric Metallicities of the Small and Large Magellanic Clouds

Science.gov (United States)

Miller, Amy Elizabeth

2018-06-01

In the field of astronomy, the study of galaxies is vitally important to understanding the structure and evolution of the universe. Within the study of galaxies, of particular interest are the Small and Large Magellanic Clouds (SMC and LMC, respectively), two of the Milky Way’s closest and most massive satellite galaxies. Their close proximity make them ideal candidates for understanding astrophysical processes such as galaxy interactions. In order to fully understand the Magellanic Clouds, it is imperative that the metallicity of the clouds be mapped in detail. In order to accomplish this task, I will use data from the Survey of Magellanic Stellar History (SMASH) which is a deep, multi-band (ugriz) photometric survey of the Magellanic Clouds that contains approximately 400 million objects in 197 fully-calibrated fields. SMASH is an extensive and deep photometric data set that enables the full-scale study of the galactic structure in the Clouds. The SMASH u-band is sensitive to metallicity for main-sequence turn-off stars which we calibrate using SDSS spectroscopy in overlapping regions (mainly standard star fields). The final steps will be to make metallicity maps of the main bodies and peripheries of the LMC and SMC. Ultimately, these metallicity maps will help us trace out population gradients in the Clouds and uncover the origin of their very extended stellar peripheries.

Cloud Computing Governance Lifecycle

Directory of Open Access Journals (Sweden)

Soňa Karkošková

2016-06-01

Full Text Available Externally provisioned cloud services enable flexible and on-demand sourcing of IT resources. Cloud computing introduces new challenges such as need of business process redefinition, establishment of specialized governance and management, organizational structures and relationships with external providers and managing new types of risk arising from dependency on external providers. There is a general consensus that cloud computing in addition to challenges brings many benefits but it is unclear how to achieve them. Cloud computing governance helps to create business value through obtain benefits from use of cloud computing services while optimizing investment and risk. Challenge, which organizations are facing in relation to governing of cloud services, is how to design and implement cloud computing governance to gain expected benefits. This paper aims to provide guidance on implementation activities of proposed Cloud computing governance lifecycle from cloud consumer perspective. Proposed model is based on SOA Governance Framework and consists of lifecycle for implementation and continuous improvement of cloud computing governance model.

The cloud understanding the security, privacy and trust challenges

CERN Document Server

Robinson, Neil; Cave, Jonathan; Starkey, Tony; Graux, Hans

2011-01-01

This report discusses how policy-makers might address the challenges and risks in respect of the security, privacy and trust aspects of cloud computing that could undermine the attainment of broader economic and societal objectives across Europe.

Continued rise of the cloud advances and trends in cloud computing

CERN Document Server

Mahmood, Zaigham

2014-01-01

Cloud computing is no-longer a novel paradigm, but instead an increasingly robust and established technology, yet new developments continue to emerge in this area. Continued Rise of the Cloud: Advances and Trends in Cloud Computing captures the state of the art in cloud technologies, infrastructures, and service delivery and deployment models. The book provides guidance and case studies on the development of cloud-based services and infrastructures from an international selection of expert researchers and practitioners. A careful analysis is provided of relevant theoretical frameworks, prac

The Relationship Between Infrared Dark Cloud and Stellar Properties

Science.gov (United States)

Calahan, Jenny; Hora, Joseph L.

2018-01-01

Massive stars are known to form within infrared dark clouds (IRDCs), but many details about how molecular clouds collapse and form stars remain poorly understood.We determine the relationship between the dark cloud mass and the population of young stellar objects (YSOs) associated with the cloud to shed light on the physical processes occurring within these star forming regions. We chose to use a sample of IRDCs and YSOs within the Cygnus-X region, a close-by giant star formation complex that has every stage of star formation represented. Using observations from IRAC, MIPS, PACS, and SPIRE on Spitzer and Herschel we identified a sample of 30,903 YSOs and 167 IRDCs. We derived the class of each YSO as well as the mass of YSO and IRDCs from the flux information. Using these parameters, as well as their locations in the cloud, we were sorted IRDC fragments into larger filaments and associate a set of YSOs with each IRDC. By measuring and comparing parameters such as YSO total mass, number of YSOs, Class 0, Class I, and Class II populations, distance from host filament, and filament mass we tested for correlations between the YSO and IRDC parameters. Using this treasure trove of information, we find that Class 0 and I objects are located more closely to their host IRDC than their Class II counterparts. We also find that high-density IRDCs are better environments for star formation than low-density IRDCs. However, we find no correlation between the total mass of the IRDC and the largest YSO mass in the IRDC, suggesting that IRDCs of any mass can have massive YSOs associated with them.The SAO REU program is funded by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant AST-1659473, and by the Smithsonian Institution.

Uncover the Cloud for Geospatial Sciences and Applications to Adopt Cloud Computing

Science.gov (United States)

Yang, C.; Huang, Q.; Xia, J.; Liu, K.; Li, J.; Xu, C.; Sun, M.; Bambacus, M.; Xu, Y.; Fay, D.

2012-12-01

Cloud computing is emerging as the future infrastructure for providing computing resources to support and enable scientific research, engineering development, and application construction, as well as work force education. On the other hand, there is a lot of doubt about the readiness of cloud computing to support a variety of scientific research, development and educations. This research is a project funded by NASA SMD to investigate through holistic studies how ready is the cloud computing to support geosciences. Four applications with different computing characteristics including data, computing, concurrent, and spatiotemporal intensities are taken to test the readiness of cloud computing to support geosciences. Three popular and representative cloud platforms including Amazon EC2, Microsoft Azure, and NASA Nebula as well as a traditional cluster are utilized in the study. Results illustrates that cloud is ready to some degree but more research needs to be done to fully implemented the cloud benefit as advertised by many vendors and defined by NIST. Specifically, 1) most cloud platform could help stand up new computing instances, a new computer, in a few minutes as envisioned, therefore, is ready to support most computing needs in an on demand fashion; 2) the load balance and elasticity, a defining characteristic, is ready in some cloud platforms, such as Amazon EC2, to support bigger jobs, e.g., needs response in minutes, while some are not ready to support the elasticity and load balance well. All cloud platform needs further research and development to support real time application at subminute level; 3) the user interface and functionality of cloud platforms vary a lot and some of them are very professional and well supported/documented, such as Amazon EC2, some of them needs significant improvement for the general public to adopt cloud computing without professional training or knowledge about computing infrastructure; 4) the security is a big concern in

Community Cloud Computing

Science.gov (United States)

Marinos, Alexandros; Briscoe, Gerard

Cloud Computing is rising fast, with its data centres growing at an unprecedented rate. However, this has come with concerns over privacy, efficiency at the expense of resilience, and environmental sustainability, because of the dependence on Cloud vendors such as Google, Amazon and Microsoft. Our response is an alternative model for the Cloud conceptualisation, providing a paradigm for Clouds in the community, utilising networked personal computers for liberation from the centralised vendor model. Community Cloud Computing (C3) offers an alternative architecture, created by combing the Cloud with paradigms from Grid Computing, principles from Digital Ecosystems, and sustainability from Green Computing, while remaining true to the original vision of the Internet. It is more technically challenging than Cloud Computing, having to deal with distributed computing issues, including heterogeneous nodes, varying quality of service, and additional security constraints. However, these are not insurmountable challenges, and with the need to retain control over our digital lives and the potential environmental consequences, it is a challenge we must pursue.

Cloud Computing Law

CERN Document Server

Millard, Christopher

2013-01-01

This book is about the legal implications of cloud computing. In essence, ‘the cloud’ is a way of delivering computing resources as a utility service via the internet. It is evolving very rapidly with substantial investments being made in infrastructure, platforms and applications, all delivered ‘as a service’. The demand for cloud resources is enormous, driven by such developments as the deployment on a vast scale of mobile apps and the rapid emergence of ‘Big Data’. Part I of this book explains what cloud computing is and how it works. Part II analyses contractual relationships between cloud service providers and their customers, as well as the complex roles of intermediaries. Drawing on primary research conducted by the Cloud Legal Project at Queen Mary University of London, cloud contracts are analysed in detail, including the appropriateness and enforceability of ‘take it or leave it’ terms of service, as well as the scope for negotiating cloud deals. Specific arrangements for public sect...

Tropical High Cloud Fraction Controlled by Cloud Lifetime Rather Than Clear-sky Convergence

Science.gov (United States)

Seeley, J.; Jeevanjee, N.; Romps, D. M.

2016-12-01

Observations and simulations show a peak in cloud fraction below the tropopause. This peak is usually attributed to a roughly co-located peak in radiatively-driven clear-sky convergence, which is presumed to force convective detrainment and thus promote large cloud fraction. Using simulations of radiative-convective equilibrium forced by various radiative cooling profiles, we refute this mechanism by showing that an upper-tropospheric peak in cloud fraction persists even in simulations with no peak in clear-sky convergence. Instead, cloud fraction profiles seem to be controlled by cloud lifetimes — i.e., how long it takes for clouds to dissipate after they have detrained. A simple model of cloud evaporation shows that the small saturation deficit in the upper troposphere greatly extends cloud lifetimes there, while the large saturation deficit in the lower troposphere causes condensate to evaporate quickly. Since cloud mass flux must go to zero at the tropopause, a peak in cloud fraction emerges at a "sweet spot" below the tropopause where cloud lifetimes are long and there is still sufficient mass flux to be detrained.

Cloud Computing: A study of cloud architecture and its patterns

OpenAIRE

Mandeep Handa,; Shriya Sharma

2015-01-01

Cloud computing is a general term for anything that involves delivering hosted services over the Internet. Cloud computing is a paradigm shift following the shift from mainframe to client–server in the early 1980s. Cloud computing can be defined as accessing third party software and services on web and paying as per usage. It facilitates scalability and virtualized resources over Internet as a service providing cost effective and scalable solution to customers. Cloud computing has...

Teaching Thousands with Cloud-based GIS

Science.gov (United States)

Gould, Michael; DiBiase, David; Beale, Linda

2016-04-01

Teaching Thousands with Cloud-based GIS Educators often draw a distinction between "teaching about GIS" and "teaching with GIS." Teaching about GIS involves helping students learn what GIS is, what it does, and how it works. On the other hand, teaching with GIS involves using the technology as a means to achieve education objectives in the sciences, social sciences, professional disciplines like engineering and planning, and even the humanities. The same distinction applies to CyberGIS. Understandably, early efforts to develop CyberGIS curricula and educational resources tend to be concerned primarily with CyberGIS itself. However, if CyberGIS becomes as functional, usable and scalable as it aspires to be, teaching with CyberGIS has the potential to enable large and diverse global audiences to perform spatial analysis using hosted data, mapping and analysis services all running in the cloud. Early examples of teaching tens of thousands of students across the globe with cloud-based GIS include the massive open online courses (MOOCs) offered by Penn State University and others, as well as the series of MOOCs more recently developed and offered by Esri. In each case, ArcGIS Online was used to help students achieve educational objectives in subjects like business, geodesign, geospatial intelligence, and spatial analysis, as well as mapping. Feedback from the more than 100,000 total student participants to date, as well as from the educators and staff who supported these offerings, suggest that online education with cloud-based GIS is scalable to very large audiences. Lessons learned from the course design, development, and delivery of these early examples may be useful in informing the continuing development of CyberGIS education. While MOOCs may have passed the peak of their "hype cycle" in higher education, the phenomenon they revealed persists: namely, a global mass market of educated young adults who turn to free online education to expand their horizons. The

Information Security Management as a Bridge in Cloud Systems from Private to Public Organizations

Directory of Open Access Journals (Sweden)

Myeonggil Choi

2015-08-01

Full Text Available Cloud computing has made it possible for private companies to make rapid changes in their computing environments. However, in the public sector, security issues hinder institutions from adopting cloud computing. To solve these security challenges, in this paper, we propose a methodology for information security management, which quantitatively classifies the importance of information in cloud systems in the public sector. In this study, we adopt a Delphi approach to establish the classification criteria of the proposed methodology in an objective and systematic manner. Further, through a case study of a public corporation, we try to validate the usefulness of the proposed methodology. The results of this study will help public institutions to consider introducing cloud computing and to manage cloud systems effectively and securely.

The use of cloud computing services by Portuguese’s Small and Medium Enterprises (SMEs) : a study which aims to understand to what extent are Portuguese’s SMEs managers using and managing cloud computing services

OpenAIRE

Duarte, Diogo Miguel de Abreu

2012-01-01

The objective of this dissertation is to understand to what extent are the Portuguese SMEs using and managing Cloud Computing services. This work strives to understand if the managers of the Portuguese SMEs are knowledgeable to embrace this technology, and identify which areas of the Portuguese SMEs’ value chain is Cloud Computing being currently applied and which areas are expected to be explored in the future. In order to address the main objective of this dissertation, an on-line questi...

Quantifying Diurnal Cloud Radiative Effects by Cloud Type in the Tropical Western Pacific

Energy Technology Data Exchange (ETDEWEB)

Burleyson, Casey D.; Long, Charles N.; Comstock, Jennifer M.

2015-06-01

Cloud radiative effects are examined using long-term datasets collected at the three Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facilities in the tropical western Pacific. We quantify the surface radiation budget, cloud populations, and cloud radiative effects by partitioning the data by cloud type, time of day, and as a function of large scale modes of variability such as El Niño Southern Oscillation (ENSO) phase and wet/dry seasons at Darwin. The novel facet of our analysis is that we break aggregate cloud radiative effects down by cloud type across the diurnal cycle. The Nauru cloud populations and subsequently the surface radiation budget are strongly impacted by ENSO variability whereas the cloud populations over Manus only shift slightly in response to changes in ENSO phase. The Darwin site exhibits large seasonal monsoon related variations. We show that while deeper convective clouds have a strong conditional influence on the radiation reaching the surface, their limited frequency reduces their aggregate radiative impact. The largest source of shortwave cloud radiative effects at all three sites comes from low clouds. We use the observations to demonstrate that potential model biases in the amplitude of the diurnal cycle and mean cloud frequency would lead to larger errors in the surface energy budget compared to biases in the timing of the diurnal cycle of cloud frequency. Our results provide solid benchmarks to evaluate model simulations of cloud radiative effects in the tropics.

AIRS-CloudSat cloud mask, radar reflectivities, and cloud classification matchups V3.2

Data.gov (United States)

National Aeronautics and Space Administration — This is AIRS-CloudSat collocated subset, in NetCDF 4 format. These data contain collocated: AIRS Level 1b radiances spectra, CloudSat radar reflectivities, and MODIS...

Cloud Computing (1/2)

CERN Multimedia

CERN. Geneva

2012-01-01

Cloud computing, the recent years buzzword for distributed computing, continues to attract and keep the interest of both the computing and business world. These lectures aim at explaining "What is Cloud Computing?" identifying and analyzing it's characteristics, models, and applications. The lectures will explore different "Cloud definitions" given by different authors and use them to introduce the particular concepts. The main cloud models (SaaS, PaaS, IaaS), cloud types (public, private, hybrid), cloud standards and security concerns will be presented. The borders between Cloud Computing and Grid Computing, Server Virtualization, Utility Computing will be discussed and analyzed.

Cloud Computing (2/2)

CERN Multimedia

CERN. Geneva

2012-01-01

Cloud computing, the recent years buzzword for distributed computing, continues to attract and keep the interest of both the computing and business world. These lectures aim at explaining "What is Cloud Computing?" identifying and analyzing it's characteristics, models, and applications. The lectures will explore different "Cloud definitions" given by different authors and use them to introduce the particular concepts. The main cloud models (SaaS, PaaS, IaaS), cloud types (public, private, hybrid), cloud standards and security concerns will be presented. The borders between Cloud Computing and Grid Computing, Server Virtualization, Utility Computing will be discussed and analyzed.

Marine cloud brightening

OpenAIRE

Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John

2012-01-01

The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could—subject to satisfactory resolution of technical and scientific problems identi...

Cloud4Psi: cloud computing for 3D protein structure similarity searching.

Science.gov (United States)

Mrozek, Dariusz; Małysiak-Mrozek, Bożena; Kłapciński, Artur

2014-10-01

Popular methods for 3D protein structure similarity searching, especially those that generate high-quality alignments such as Combinatorial Extension (CE) and Flexible structure Alignment by Chaining Aligned fragment pairs allowing Twists (FATCAT) are still time consuming. As a consequence, performing similarity searching against large repositories of structural data requires increased computational resources that are not always available. Cloud computing provides huge amounts of computational power that can be provisioned on a pay-as-you-go basis. We have developed the cloud-based system that allows scaling of the similarity searching process vertically and horizontally. Cloud4Psi (Cloud for Protein Similarity) was tested in the Microsoft Azure cloud environment and provided good, almost linearly proportional acceleration when scaled out onto many computational units. Cloud4Psi is available as Software as a Service for testing purposes at: http://cloud4psi.cloudapp.net/. For source code and software availability, please visit the Cloud4Psi project home page at http://zti.polsl.pl/dmrozek/science/cloud4psi.htm. © The Author 2014. Published by Oxford University Press.

CloudTPS: Scalable Transactions for Web Applications in the Cloud

NARCIS (Netherlands)

Zhou, W.; Pierre, G.E.O.; Chi, C.-H.

2010-01-01

NoSQL Cloud data services provide scalability and high availability properties for web applications but at the same time they sacrifice data consistency. However, many applications cannot afford any data inconsistency. CloudTPS is a scalable transaction manager to allow cloud database services to

Lost in Cloud

Science.gov (United States)

Maluf, David A.; Shetye, Sandeep D.; Chilukuri, Sri; Sturken, Ian

2012-01-01

Cloud computing can reduce cost significantly because businesses can share computing resources. In recent years Small and Medium Businesses (SMB) have used Cloud effectively for cost saving and for sharing IT expenses. With the success of SMBs, many perceive that the larger enterprises ought to move into Cloud environment as well. Government agency s stove-piped environments are being considered as candidates for potential use of Cloud either as an enterprise entity or pockets of small communities. Cloud Computing is the delivery of computing as a service rather than as a product, whereby shared resources, software, and information are provided to computers and other devices as a utility over a network. Underneath the offered services, there exists a modern infrastructure cost of which is often spread across its services or its investors. As NASA is considered as an Enterprise class organization, like other enterprises, a shift has been occurring in perceiving its IT services as candidates for Cloud services. This paper discusses market trends in cloud computing from an enterprise angle and then addresses the topic of Cloud Computing for NASA in two possible forms. First, in the form of a public Cloud to support it as an enterprise, as well as to share it with the commercial and public at large. Second, as a private Cloud wherein the infrastructure is operated solely for NASA, whether managed internally or by a third-party and hosted internally or externally. The paper addresses the strengths and weaknesses of both paradigms of public and private Clouds, in both internally and externally operated settings. The content of the paper is from a NASA perspective but is applicable to any large enterprise with thousands of employees and contractors.

RenderSelect: a Cloud Broker Framework for Cloud Renderfarm Services

OpenAIRE

Ruby, Annette J; Aisha, Banu W; Subash, Chandran P

2016-01-01

In the 3D studios the animation scene files undergo a process called as rendering, where the 3D wire frame models are converted into 3D photorealistic images. As the rendering process is both a computationally intensive and a time consuming task, the cloud services based rendering in cloud render farms is gaining popularity among the animators. Though cloud render farms offer many benefits, the animators hesitate to move from their traditional offline rendering to cloud services based render ...

Determination of the impact of RGB points cloud attribute quality on color-based segmentation process

Directory of Open Access Journals (Sweden)

Bartłomiej Kraszewski

2015-06-01

Full Text Available The article presents the results of research on the effect that radiometric quality of point cloud RGB attributes have on color-based segmentation. In the research, a point cloud with a resolution of 5 mm, received from FAROARO Photon 120 scanner, described the fragment of an office’s room and color images were taken by various digital cameras. The images were acquired by SLR Nikon D3X, and SLR Canon D200 integrated with the laser scanner, compact camera Panasonic TZ-30 and a mobile phone digital camera. Color information from images was spatially related to point cloud in FAROARO Scene software. The color-based segmentation of testing data was performed with the use of a developed application named “RGB Segmentation”. The application was based on public Point Cloud Libraries (PCL and allowed to extract subsets of points fulfilling the criteria of segmentation from the source point cloud using region growing method.Using the developed application, the segmentation of four tested point clouds containing different RGB attributes from various images was performed. Evaluation of segmentation process was performed based on comparison of segments acquired using the developed application and extracted manually by an operator. The following items were compared: the number of obtained segments, the number of correctly identified objects and the correctness of segmentation process. The best correctness of segmentation and most identified objects were obtained using the data with RGB attribute from Nikon D3X images. Based on the results it was found that quality of RGB attributes of point cloud had impact only on the number of identified objects. In case of correctness of the segmentation, as well as its error no apparent relationship between the quality of color information and the result of the process was found.[b]Keywords[/b]: terrestrial laser scanning, color-based segmentation, RGB attribute, region growing method, digital images, points cloud

AN ADAPTIVE APPROACH FOR SEGMENTATION OF 3D LASER POINT CLOUD

Directory of Open Access Journals (Sweden)

Z. Lari

2012-09-01

Full Text Available Automatic processing and object extraction from 3D laser point cloud is one of the major research topics in the field of photogrammetry. Segmentation is an essential step in the processing of laser point cloud, and the quality of extracted objects from laser data is highly dependent on the validity of the segmentation results. This paper presents a new approach for reliable and efficient segmentation of planar patches from a 3D laser point cloud. In this method, the neighbourhood of each point is firstly established using an adaptive cylinder while considering the local point density and surface trend. This neighbourhood definition has a major effect on the computational accuracy of the segmentation attributes. In order to efficiently cluster planar surfaces and prevent introducing ambiguities, the coordinates of the origin's projection on each point's best fitted plane are used as the clustering attributes. Then, an octree space partitioning method is utilized to detect and extract peaks from the attribute space. Each detected peak represents a specific cluster of points which are located on a distinct planar surface in the object space. Experimental results show the potential and feasibility of applying this method for segmentation of both airborne and terrestrial laser data.

SOFIA FORCAST Far-IR Photometry of Comet ISON and Constraints on the Coma Grain Size Distribution

Science.gov (United States)

Wooden, D. H.; DeBuizer, J. M.; Kelley, M. S.; Woodward, C. E.; Harker, D. E.; Reach, W. T.; Sitko, M. L.; Russell, R. W.; Gehrz, R. D.; dePater, Imke;

Comparison of cloud optical depth and cloud mask applying BRDF model-based background surface reflectance

Science.gov (United States)

Kim, H. W.; Yeom, J. M.; Woo, S. H.

2017-12-01

Over the thin cloud region, satellite can simultaneously detect the reflectance from thin clouds and land surface. Since the mixed reflectance is not the exact cloud information, the background surface reflectance should be eliminated to accurately distinguish thin cloud such as cirrus. In the previous research, Kim et al (2017) was developed the cloud masking algorithm using the Geostationary Ocean Color Imager (GOCI), which is one of significant instruments for Communication, Ocean, and Meteorology Satellite (COMS). Although GOCI has 8 spectral channels including visible and near infra-red spectral ranges, the cloud masking has quantitatively reasonable result when comparing with MODIS cloud mask (Collection 6 MYD35). Especially, we noticed that this cloud masking algorithm is more specialized in thin cloud detections through the validation with Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Because this cloud masking method was concentrated on eliminating background surface effects from the top-of-atmosphere (TOA) reflectance. Applying the difference between TOA reflectance and the bi-directional reflectance distribution function (BRDF) model-based background surface reflectance, cloud areas both thick cloud and thin cloud can be discriminated without infra-red channels which were mostly used for detecting clouds. Moreover, when the cloud mask result was utilized as the input data when simulating BRDF model and the optimized BRDF model-based surface reflectance was used for the optimized cloud masking, the probability of detection (POD) has higher value than POD of the original cloud mask. In this study, we examine the correlation between cloud optical depth (COD) and its cloud mask result. Cloud optical depths mostly depend on the cloud thickness, the characteristic of contents, and the size of cloud contents. COD ranges from less than 0.1 for thin clouds to over 1000 for the huge cumulus due to scattering by droplets. With

A Framework to Improve Communication and Reliability Between Cloud Consumer and Provider in the Cloud

OpenAIRE

Vivek Sridhar

2014-01-01

Cloud services consumers demand reliable methods for choosing appropriate cloud service provider for their requirements. Number of cloud consumer is increasing day by day and so cloud providers, hence requirement for a common platform for interacting between cloud provider and cloud consumer is also on the raise. This paper introduces Cloud Providers Market Platform Dashboard. This will act as not only just cloud provider discoverability but also provide timely report to consumer on cloud ser...

Moving towards Cloud Security

OpenAIRE

Edit Szilvia Rubóczki; Zoltán Rajnai

2015-01-01

Cloud computing hosts and delivers many different services via Internet. There are a lot of reasons why people opt for using cloud resources. Cloud development is increasing fast while a lot of related services drop behind, for example the mass awareness of cloud security. However the new generation upload videos and pictures without reason to a cloud storage, but only few know about data privacy, data management and the proprietary of stored data in the cloud. In an enterprise environment th...

Cloud Computing Value Chains: Understanding Businesses and Value Creation in the Cloud

Science.gov (United States)

Mohammed, Ashraf Bany; Altmann, Jörn; Hwang, Junseok

Based on the promising developments in Cloud Computing technologies in recent years, commercial computing resource services (e.g. Amazon EC2) or software-as-a-service offerings (e.g. Salesforce. com) came into existence. However, the relatively weak business exploitation, participation, and adoption of other Cloud Computing services remain the main challenges. The vague value structures seem to be hindering business adoption and the creation of sustainable business models around its technology. Using an extensive analyze of existing Cloud business models, Cloud services, stakeholder relations, market configurations and value structures, this Chapter develops a reference model for value chains in the Cloud. Although this model is theoretically based on porter's value chain theory, the proposed Cloud value chain model is upgraded to fit the diversity of business service scenarios in the Cloud computing markets. Using this model, different service scenarios are explained. Our findings suggest new services, business opportunities, and policy practices for realizing more adoption and value creation paths in the Cloud.

Cloud vertical structure, precipitation, and cloud radiative effects over Tibetan Plateau

Science.gov (United States)

Liu, Y.; Yan, Y.; Lu, J.

2017-12-01

The vertical structure of clouds and its connection with precipitation and cloud radiative effects (CRE) over the Tibetan Plateau (TP) are analyzed and compared with its neighboring land and tropical oceans based on CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) products and the Tropical Rainfall Measuring Mission (TRMM) precipitation data. Unique characteristics of cloud vertical structure and CRE over the TP are found. The cloud amount shows seasonal variation over the TP, which presents a single peak (located in 7-11 km) during January to April and two peaks (located in 5-8 km and 11-17 km separately) after mid-June, and then resumes to one peak (located in 5-10 km) after mid-August. Topography-induced restriction on moisture supply leads to a compression effect on clouds, i.e., the reduction in both cloud thickness and number of cloud layers, over the TP. The topography-induced compression effect is also shown in the range in the variation of cloud thickness and cloud-top height corresponding to different precipitation intensity, which is much smaller over the TP than its neighboring regions. In summer, cloud ice particles over the TP are mostly located at lower altitude (5-10 km) with richer variety of sizes and aggregation in no rain conditions compared to other regions. Ice water content becomes abundant and the number concentration tends to be dense at higher levels when precipitation is enhanced. The longwave CRE in the atmosphere over the TP is a net cooling effect. The vertical structure of CRE over the TP is unique compared to other regions: there exists a strong cooling layer of net CRE at the altitude of 8 km, from June to the beginning of October; the net radiative heating layer above the surface is shallower but stronger underneath 7 km and with a stronger seasonal variation over the TP.

HOW COMMON ARE THE MAGELLANIC CLOUDS?

International Nuclear Information System (INIS)

Liu, Lulu; Gerke, Brian F.; Wechsler, Risa H.; Behroozi, Peter S.; Busha, Michael T.

2011-01-01

We introduce a probabilistic approach to the problem of counting dwarf satellites around host galaxies in databases with limited redshift information. This technique is used to investigate the occurrence of satellites with luminosities similar to the Magellanic Clouds around hosts with properties similar to the Milky Way (MW) in the object catalog of the Sloan Digital Sky Survey (SDSS). Our analysis uses data from SDSS Data Release 7, selecting candidate MW-like hosts from the spectroscopic catalog and candidate analogs of the Magellanic Clouds from the photometric catalog. Our principal result is the probability for an MW-like galaxy to host N sat close satellites with luminosities similar to the Magellanic Clouds. We find that 81% of galaxies like the MW have no such satellites within a radius of 150 kpc, 11% have one, and only 3.5% of hosts have two. The probabilities are robust to changes in host and satellite selection criteria, background-estimation technique, and survey depth. These results demonstrate that the MW has significantly more satellites than a typical galaxy of its luminosity; this fact is useful for understanding the larger cosmological context of our home galaxy.

The Magellanic clouds

International Nuclear Information System (INIS)

1989-01-01

As the two galaxies nearest to our own, the Magellanic Clouds hold a special place in studies of the extragalactic distance scale, of stellar evolution and the structure of galaxies. In recent years, results from the South African Astronomical Observatory (SAAO) and elsewhere have shown that it is possible to begin understanding the three dimensional structure of the Clouds. Studies of Magellanic Cloud Cepheids have continued, both to investigate the three-dimensional structure of the Clouds and to learn more about Cepheids and their use as extragalactic distance indicators. Other research undertaken at SAAO includes studies on Nova LMC 1988 no 2 and red variables in the Magellanic Clouds

Cloud Computing Quality

Directory of Open Access Journals (Sweden)

Anamaria Şiclovan

2013-02-01

Full Text Available Cloud computing was and it will be a new way of providing Internet services and computers. This calculation approach is based on many existing services, such as the Internet, grid computing, Web services. Cloud computing as a system aims to provide on demand services more acceptable as price and infrastructure. It is exactly the transition from computer to a service offered to the consumers as a product delivered online. This paper is meant to describe the quality of cloud computing services, analyzing the advantages and characteristics offered by it. It is a theoretical paper.Keywords: Cloud computing, QoS, quality of cloud computing

Target of Opportunity - Far-UV Observations of Comet ISON with FORTIS

Science.gov (United States)

McCandliss, Stephan

The goal of this one year program is to acquire spectra and imagery of the sungrazing Oort cloud comet known as ISON in the far-UV bandpass between 800 -- 1950 Angstroms over a 1/2 degree field-of-view (FOV), during its ingress and egress from the sun. This bandpass and FOV provides access to a particularly rich set of spectral diagnostics for determining the volatile production rates of CO, H, C, C+, O and S, and to search for previously undetected atomic and molecular species such as Ar, N, N+, N2, O+ and O5+. We are particularly interested in searching for compositional changes associated with the intense heating episode at the comet's perihelion to address an outstanding question in cometary research; do Oort cloud comets carry a chemical composition similar to the proto-stellar molecular cloud from which the Solar System formed? Sounding rockets are uniquely suited to observing cometary emissions in the far-UV as they can point to within 25 degrees of the sun, whereas HST is limited to observations at angles greater than 50 degrees. The projected ephemeris of this comet shows that on ingress it is expected to reach ~ +4 mag at 25 degrees from the sun on 21 November 2013 and, should it survive its trip to within 2.7 Rsun from the sun, it is expected to reach a similar magnitude during egress at 25 degrees on 08 December 2013. This will be a reflight of the JHU sounding rocket borne spectro-telescope called FORTIS, currently scheduled to fly in May of 2013 on NASA sounding rocket 36.268 UG. The instrumental configuration of FORTIS is uniquely suited to accomplishing the goals of this task.

Cloud Infrastructure Security

OpenAIRE

Velev , Dimiter; Zlateva , Plamena

2010-01-01

Part 4: Security for Clouds; International audience; Cloud computing can help companies accomplish more by eliminating the physical bonds between an IT infrastructure and its users. Users can purchase services from a cloud environment that could allow them to save money and focus on their core business. At the same time certain concerns have emerged as potential barriers to rapid adoption of cloud services such as security, privacy and reliability. Usually the information security professiona...

Cloud security mechanisms

OpenAIRE

2014-01-01

Cloud computing has brought great benefits in cost and flexibility for provisioning services. The greatest challenge of cloud computing remains however the question of security. The current standard tools in access control mechanisms and cryptography can only partly solve the security challenges of cloud infrastructures. In the recent years of research in security and cryptography, novel mechanisms, protocols and algorithms have emerged that offer new ways to create secure services atop cloud...

Spectral Dependence of MODIS Cloud Droplet Effective Radius Retrievals for Marine Boundary Layer Clouds

Science.gov (United States)

Zhang, Zhibo; Platnick, Steven E.; Ackerman, Andrew S.; Cho, Hyoun-Myoung

2014-01-01

Low-level warm marine boundary layer (MBL) clouds cover large regions of Earth's surface. They have a significant role in Earth's radiative energy balance and hydrological cycle. Despite the fundamental role of low-level warm water clouds in climate, our understanding of these clouds is still limited. In particular, connections between their properties (e.g. cloud fraction, cloud water path, and cloud droplet size) and environmental factors such as aerosol loading and meteorological conditions continue to be uncertain or unknown. Modeling these clouds in climate models remains a challenging problem. As a result, the influence of aerosols on these clouds in the past and future, and the potential impacts of these clouds on global warming remain open questions leading to substantial uncertainty in climate projections. To improve our understanding of these clouds, we need continuous observations of cloud properties on both a global scale and over a long enough timescale for climate studies. At present, satellite-based remote sensing is the only means of providing such observations.

Risk in the Clouds?: Security Issues Facing Government Use of Cloud Computing

Science.gov (United States)

Wyld, David C.

Cloud computing is poised to become one of the most important and fundamental shifts in how computing is consumed and used. Forecasts show that government will play a lead role in adopting cloud computing - for data storage, applications, and processing power, as IT executives seek to maximize their returns on limited procurement budgets in these challenging economic times. After an overview of the cloud computing concept, this article explores the security issues facing public sector use of cloud computing and looks to the risk and benefits of shifting to cloud-based models. It concludes with an analysis of the challenges that lie ahead for government use of cloud resources.

GIANT MOLECULAR CLOUD FORMATION IN DISK GALAXIES: CHARACTERIZING SIMULATED VERSUS OBSERVED CLOUD CATALOGS

Energy Technology Data Exchange (ETDEWEB)

Benincasa, Samantha M.; Pudritz, Ralph E.; Wadsley, James [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Tasker, Elizabeth J. [Department of Physics, Faculty of Science, Hokkaido University, Kita-ku, Sapporo 060-0810 (Japan)

2013-10-10

We present the results of a study of simulated giant molecular clouds (GMCs) formed in a Milky Way-type galactic disk with a flat rotation curve. This simulation, which does not include star formation or feedback, produces clouds with masses ranging between 10{sup 4} M{sub ☉} and 10{sup 7} M{sub ☉}. We compare our simulated cloud population to two observational surveys: the Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey and the BIMA All-Disk Survey of M33. An analysis of the global cloud properties as well as a comparison of Larson's scaling relations is carried out. We find that simulated cloud properties agree well with the observed cloud properties, with the closest agreement occurring between the clouds at comparable resolution in M33. Our clouds are highly filamentary—a property that derives both from their formation due to gravitational instability in the sheared galactic environment, as well as to cloud-cloud gravitational encounters. We also find that the rate at which potentially star-forming gas accumulates within dense regions—wherein n{sub thresh} ≥ 10{sup 4} cm{sup –3}—is 3% per 10 Myr, in clouds of roughly 10{sup 6} M{sub ☉}. This suggests that star formation rates in observed clouds are related to the rates at which gas can be accumulated into dense subregions within GMCs via filamentary flows. The most internally well-resolved clouds are chosen for listing in a catalog of simulated GMCs—the first of its kind. The cataloged clouds are available as an extracted data set from the global simulation.

Estimating Aircraft Heading Based on Laserscanner Derived Point Clouds

Science.gov (United States)

Koppanyi, Z.; Toth, C., K.

2015-03-01

Using LiDAR sensors for tracking and monitoring an operating aircraft is a new application. In this paper, we present data processing methods to estimate the heading of a taxiing aircraft using laser point clouds. During the data acquisition, a Velodyne HDL-32E laser scanner tracked a moving Cessna 172 airplane. The point clouds captured at different times were used for heading estimation. After addressing the problem and specifying the equation of motion to reconstruct the aircraft point cloud from the consecutive scans, three methods are investigated here. The first requires a reference model to estimate the relative angle from the captured data by fitting different cross-sections (horizontal profiles). In the second approach, iterative closest point (ICP) method is used between the consecutive point clouds to determine the horizontal translation of the captured aircraft body. Regarding the ICP, three different versions were compared, namely, the ordinary 3D, 3-DoF 3D and 2-DoF 3D ICP. It was found that 2-DoF 3D ICP provides the best performance. Finally, the last algorithm searches for the unknown heading and velocity parameters by minimizing the volume of the reconstructed plane. The three methods were compared using three test datatypes which are distinguished by object-sensor distance, heading and velocity. We found that the ICP algorithm fails at long distances and when the aircraft motion direction perpendicular to the scan plane, but the first and the third methods give robust and accurate results at 40m object distance and at ~12 knots for a small Cessna airplane.

Comparison of Monthly Mean Cloud Fraction and Cloud Optical depth Determined from Surface Cloud Radar, TOVS, AVHRR, and MODIS over Barrow, Alaska

Science.gov (United States)

Uttal, Taneil; Frisch, Shelby; Wang, Xuan-Ji; Key, Jeff; Schweiger, Axel; Sun-Mack, Sunny; Minnis, Patrick

2005-01-01

A one year comparison is made of mean monthly values of cloud fraction and cloud optical depth over Barrow, Alaska (71 deg 19.378 min North, 156 deg 36.934 min West) between 35 GHz radar-based retrievals, the TOVS Pathfinder Path-P product, the AVHRR APP-X product, and a MODIS based cloud retrieval product from the CERES-Team. The data sets represent largely disparate spatial and temporal scales, however, in this paper, the focus is to provide a preliminary analysis of how the mean monthly values derived from these different data sets compare, and determine how they can best be used separately, and in combination to provide reliable estimates of long-term trends of changing cloud properties. The radar and satellite data sets described here incorporate Arctic specific modifications that account for cloud detection challenges specific to the Arctic environment. The year 2000 was chosen for this initial comparison because the cloud radar data was particularly continuous and reliable that year, and all of the satellite retrievals of interest were also available for the year 2000. Cloud fraction was chosen as a comparison variable as accurate detection of cloud is the primary product that is necessary for any other cloud property retrievals. Cloud optical depth was additionally selected as it is likely the single cloud property that is most closely correlated to cloud influences on surface radiation budgets.

Star clouds of Magellan

International Nuclear Information System (INIS)

Tucker, W.

1981-01-01

The Magellanic Clouds are two irregular galaxies belonging to the local group which the Milky Way belongs to. By studying the Clouds, astronomers hope to gain insight into the origin and composition of the Milky Way. The overall structure and dynamics of the Clouds are clearest when studied in radio region of the spectrum. One benefit of directly observing stellar luminosities in the Clouds has been the discovery of the period-luminosity relation. Also, the Clouds are a splendid laboratory for studying stellar evolution. It is believed that both Clouds may be in the very early stage in the development of a regular, symmetric galaxy. This raises a paradox because some of the stars in the star clusters of the Clouds are as old as the oldest stars in our galaxy. An explanation for this is given. The low velocity of the Clouds with respect to the center of the Milky Way shows they must be bound to it by gravity. Theories are given on how the Magellanic Clouds became associated with the galaxy. According to current ideas the Clouds orbits will decay and they will spiral into the Galaxy

Factors influencing the organizational adoption of cloud computing: a survey among cloud workers

Directory of Open Access Journals (Sweden)

Mark Stieninger

2018-01-01

Full Text Available Cloud computing presents an opportunity for organizations to leverage affordable, scalable, and agile technologies. However, even with the demonstrated value of cloud computing, organizations have been hesitant to adopt such technologies. Based on a multi-theoretical research model, this paper provides an empirical study targeted to better understand the adoption of cloud services. An online survey addressing the factors derived from literature for three specific popular cloud application types (cloud storage, cloud mail and cloud office was undertaken. The research model was analyzed by using variance-based structural equation modelling. Results show that the factors of compatibility, relative advantage, security and trust, as well as, a lower level of complexity lead to a more positive attitude towards cloud adoption. Complexity, compatibility, image and security and trust have direct and indirect effects on relative advantage. These factors further explain a large part of the attitude towards cloud adoption but not of its usage.

Star formation induced by cloud-cloud collisions and galactic giant molecular cloud evolution

Science.gov (United States)

Kobayashi, Masato I. N.; Kobayashi, Hiroshi; Inutsuka, Shu-ichiro; Fukui, Yasuo

2018-05-01

Recent millimeter/submillimeter observations towards nearby galaxies have started to map the whole disk and to identify giant molecular clouds (GMCs) even in the regions between galactic spiral structures. Observed variations of GMC mass functions in different galactic environments indicates that massive GMCs preferentially reside along galactic spiral structures whereas inter-arm regions have many small GMCs. Based on the phase transition dynamics from magnetized warm neutral medium to molecular clouds, Kobayashi et al. (2017, ApJ, 836, 175) proposes a semi-analytical evolutionary description for GMC mass functions including a cloud-cloud collision (CCC) process. Their results show that CCC is less dominant in shaping the mass function of GMCs than the accretion of dense H I gas driven by the propagation of supersonic shock waves. However, their formulation does not take into account the possible enhancement of star formation by CCC. Millimeter/submillimeter observations within the Milky Way indicate the importance of CCC in the formation of star clusters and massive stars. In this article, we reformulate the time-evolution equation largely modified from Kobayashi et al. (2017, ApJ, 836, 175) so that we additionally compute star formation subsequently taking place in CCC clouds. Our results suggest that, although CCC events between smaller clouds are more frequent than the ones between massive GMCs, CCC-driven star formation is mostly driven by massive GMCs ≳ 10^{5.5} M_{⊙} (where M⊙ is the solar mass). The resultant cumulative CCC-driven star formation may amount to a few 10 percent of the total star formation in the Milky Way and nearby galaxies.

Hybrid cloud for dummies

CERN Document Server

Hurwitz, Judith; Halper, Fern; Kirsch, Dan

2012-01-01

Understand the cloud and implement a cloud strategy for your business Cloud computing enables companies to save money by leasing storage space and accessing technology services through the Internet instead of buying and maintaining equipment and support services. Because it has its own unique set of challenges, cloud computing requires careful explanation. This easy-to-follow guide shows IT managers and support staff just what cloud computing is, how to deliver and manage cloud computing services, how to choose a service provider, and how to go about implementation. It also covers security and

Realm of the comets

International Nuclear Information System (INIS)

Weissman, P.R.

1987-01-01

Studies of Jovian perturbations of the orbits of long-period comets led to the concept of the Oort cloud of 180 billion comets at 50,000-150,000 AU from the sun. Several comets are induced to move toward the sun every million years by the passage of a star at a distance of a few light years. The location of the cloud has since been revised to 20,000-100,000 AU, and comets are now accepted as remnant material fron the proto-solar system epoch. The galactic disk and random, close-passing stars may also cause rare, large perturbations in the orbits of the cloud comets, sending large numbers of comets through the inner solar system. The resulting cometary storm is a candidate cause for the wholesale extinction of dinosaurs in the Cretaceous-Terniary transition due to large number of planetesimals, or one large comet, striking the earth, in a short period of time. The IRAS instruments have detected similar clouds of material around other stars

Hypersonic: Model Analysis and Checking in the Cloud

DEFF Research Database (Denmark)

Acretoaie, Vlad; Störrle, Harald

2014-01-01

”. Objective: In this paper we investigate the conceptual and technical feasibility of a new software architecture for modeling tools, where certain advanced features are factored out of the client and moved towards the Cloud. With this approach we plan to address the above mentioned drawbacks of existing...

Cloud Robotics Model

OpenAIRE

Mester, Gyula

2015-01-01

Cloud Robotics was born from the merger of service robotics and cloud technologies. It allows robots to benefit from the powerful computational, storage, and communications resources of modern data centres. Cloud robotics allows robots to take advantage of the rapid increase in data transfer rates to offload tasks without hard real time requirements. Cloud Robotics has rapidly gained momentum with initiatives by companies such as Google, Willow Garage and Gostai as well as more than a dozen a...

Quantitative Measures of Immersion in Cloud and the Biogeography of Cloud Forests

Science.gov (United States)

Lawton, R. O.; Nair, U. S.; Ray, D.; Regmi, A.; Pounds, J. A.; Welch, R. M.

2010-01-01

Sites described as tropical montane cloud forests differ greatly, in part because observers tend to differ in their opinion as to what constitutes frequent and prolonged immersion in cloud. This definitional difficulty interferes with hydrologic analyses, assessments of environmental impacts on ecosystems, and biogeographical analyses of cloud forest communities and species. Quantitative measurements of cloud immersion can be obtained on site, but the observations are necessarily spatially limited, although well-placed observers can examine 10 50 km of a mountain range under rainless conditions. Regional analyses, however, require observations at a broader scale. This chapter discusses remote sensing and modeling approaches that can provide quantitative measures of the spatiotemporal patterns of cloud cover and cloud immersion in tropical mountain ranges. These approaches integrate remote sensing tools of various spatial resolutions and frequencies of observation, digital elevation models, regional atmospheric models, and ground-based observations to provide measures of cloud cover, cloud base height, and the intersection of cloud and terrain. This combined approach was applied to the Monteverde region of northern Costa Rica to illustrate how the proportion of time the forest is immersed in cloud may vary spatially and temporally. The observed spatial variation was largely due to patterns of airflow over the mountains. The temporal variation reflected the diurnal rise and fall of the orographic cloud base, which was influenced in turn by synoptic weather conditions, the seasonal movement of the Intertropical Convergence Zone and the north-easterly trade winds. Knowledge of the proportion of the time that sites are immersed in clouds should facilitate ecological comparisons and biogeographical analyses, as well as land use planning and hydrologic assessments in areas where intensive on-site work is not feasible.

Health Information System in a Cloud Computing Context.

Science.gov (United States)

Sadoughi, Farahnaz; Erfannia, Leila

2017-01-01

Healthcare as a worldwide industry is experiencing a period of growth based on health information technology. The capabilities of cloud systems make it as an option to develop eHealth goals. The main objectives of the present study was to evaluate the advantages and limitations of health information systems implementation in a cloud-computing context that was conducted as a systematic review in 2016. Science direct, Scopus, Web of science, IEEE, PubMed and Google scholar were searched according study criteria. Among 308 articles initially found, 21 articles were entered in the final analysis. All the studies had considered cloud computing as a positive tool to help advance health technology, but none had insisted too much on its limitations and threats. Electronic health record systems have been mostly studied in the fields of implementation, designing, and presentation of models and prototypes. According to this research, the main advantages of cloud-based health information systems could be categorized into the following groups: economic benefits and advantages of information management. The main limitations of the implementation of cloud-based health information systems could be categorized into the 4 groups of security, legal, technical, and human restrictions. Compared to earlier studies, the present research had the advantage of dealing with the issue of health information systems in a cloud platform. The high frequency of studies conducted on the implementation of cloud-based health information systems revealed health industry interest in the application of this technology. Security was a subject discussed in most studies due to health information sensitivity. In this investigation, some mechanisms and solutions were discussed concerning the mentioned systems, which would provide a suitable area for future scientific research on this issue. The limitations and solutions discussed in this systematic study would help healthcare managers and decision

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

Science.gov (United States)

Rosenfeld, Daniel; Zheng, Youtong; Hashimshoni, Eyal; Pöhlker, Mira L.; Jefferson, Anne; Pöhlker, Christopher; Yu, Xing; Zhu, Yannian; Liu, Guihua; Yue, Zhiguo; Fischman, Baruch; Li, Zhanqing; Giguzin, David; Goren, Tom; Artaxo, Paulo; Pöschl, Ulrich

2016-01-01

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25° restricts the satellite coverage to ∼25% of the world area in a single day. PMID:26944081

Cloud computing basics

CERN Document Server

Srinivasan, S

2014-01-01

Cloud Computing Basics covers the main aspects of this fast moving technology so that both practitioners and students will be able to understand cloud computing. The author highlights the key aspects of this technology that a potential user might want to investigate before deciding to adopt this service. This book explains how cloud services can be used to augment existing services such as storage, backup and recovery. Addressing the details on how cloud security works and what the users must be prepared for when they move their data to the cloud. Also this book discusses how businesses could prepare for compliance with the laws as well as industry standards such as the Payment Card Industry.

Moving towards Cloud Security

Directory of Open Access Journals (Sweden)

Edit Szilvia Rubóczki

2015-01-01

Full Text Available Cloud computing hosts and delivers many different services via Internet. There are a lot of reasons why people opt for using cloud resources. Cloud development is increasing fast while a lot of related services drop behind, for example the mass awareness of cloud security. However the new generation upload videos and pictures without reason to a cloud storage, but only few know about data privacy, data management and the proprietary of stored data in the cloud. In an enterprise environment the users have to know the rule of cloud usage, however they have little knowledge about traditional IT security. It is important to measure the level of their knowledge, and evolve the training system to develop the security awareness. The article proves the importance of suggesting new metrics and algorithms for measuring security awareness of corporate users and employees to include the requirements of emerging cloud security.

Cloud Usage Patterns : A Formalism for Description of Cloud Usage Scenarios

NARCIS (Netherlands)

Milenkoski, Aleksandar; Iosup, Alexandru; Kounev, Samuel; Sachs, Kai; Rygielski, Piotr; Ding, Jason; Cirne, Walfredo; Rosenberg, Florian

2014-01-01

Cloud computing is becoming an increasingly lucrative branch of the existing information and communication technologies (ICT). Enabling a debate about cloud usage scenarios can help with attracting new customers, sharing best-practices, and designing new cloud services. In contrast to previous

Mobile Clouds

DEFF Research Database (Denmark)

Fitzek, Frank; Katz, Marcos

A mobile cloud is a cooperative arrangement of dynamically connected communication nodes sharing opportunistic resources. In this book, authors provide a comprehensive and motivating overview of this rapidly emerging technology. The book explores how distributed resources can be shared by mobile...... users in very different ways and for various purposes. The book provides many stimulating examples of resource-sharing applications. Enabling technologies for mobile clouds are also discussed, highlighting the key role of network coding. Mobile clouds have the potential to enhance communications...... performance, improve utilization of resources and create flexible platforms to share resources in very novel ways. Energy efficient aspects of mobile clouds are discussed in detail, showing how being cooperative can bring mobile users significant energy saving. The book presents and discusses multiple...

pCloud: A Cloud-based Power Market Simulation Environment

Energy Technology Data Exchange (ETDEWEB)

Rudkevich, Aleksandr; Goldis, Evgeniy

2012-12-02

This research conducted by the Newton Energy Group, LLC (NEG) is dedicated to the development of pCloud: a Cloud-based Power Market Simulation Environment. pCloud is offering power industry stakeholders the capability to model electricity markets and is organized around the Software as a Service (SaaS) concept -- a software application delivery model in which software is centrally hosted and provided to many users via the internet. During the Phase I of this project NEG developed a prototype design for pCloud as a SaaS-based commercial service offering, system architecture supporting that design, ensured feasibility of key architecture's elements, formed technological partnerships and negotiated commercial agreements with partners, conducted market research and other related activities and secured funding for continue development of pCloud between the end of Phase I and beginning of Phase II, if awarded. Based on the results of Phase I activities, NEG has established that the development of a cloud-based power market simulation environment within the Windows Azure platform is technologically feasible, can be accomplished within the budget and timeframe available through the Phase II SBIR award with additional external funding. NEG believes that pCloud has the potential to become a game-changing technology for the modeling and analysis of electricity markets. This potential is due to the following critical advantages of pCloud over its competition: - Standardized access to advanced and proven power market simulators offered by third parties. - Automated parallelization of simulations and dynamic provisioning of computing resources on the cloud. This combination of automation and scalability dramatically reduces turn-around time while offering the capability to increase the number of analyzed scenarios by a factor of 10, 100 or even 1000. - Access to ready-to-use data and to cloud-based resources leading to a reduction in software, hardware, and IT costs

Molecular clouds and galactic spiral structure

International Nuclear Information System (INIS)

Dame, T.M.

1983-01-01

Galactic CO line emission at 115 GHz has been surveyed in the region 12 0 less than or equal to l less than or equal to 60 0 and -1 0 less than or equal to b less than or equal to 1 0 in order to study the distribution of molecular clouds in the inner galaxy; an inner strip 0 0 .5 wide has been sampled every beamwidth (0 0 .125), the rest every two beamwidths. Comparison of the survey with similar HI data reveals a detailed correlation with the most intense 21-cm features, implying that the CO and HI trace the same galactic features and have the same large-scale kinematics. To each of the classical 21-cm (HI) spiral arms of the inner galaxy there corresponds a CO molecular arm which is generally more clearly defined and of higher contrast. A simple model is developed in which all of the CO emission from the inner galaxy arises from spiral arms. The modeling results suggest that molecular clouds are essentially transient objects, existing for 15 to 40 million years after their formation in a spiral arm, and are largely confined to spiral features about 300 pc wide. A variety of methods are employed to estimate distances and masses for the largest clouds detected by the inner-galaxy survey and a catalogue is compiled. The catalogued clouds, the largest of which have masses of several 10 6 M/sub sunmass/ and linear dimensions in excess of 100 pc, are found to be excellent spiral-arm tracers. One of the nearest of the clouds, that associated with the supernova remnant W44, is fully mapped in both CO and 13 CO and is discussed in detail

Cloud computing strategies

CERN Document Server

Chorafas, Dimitris N

2011-01-01

A guide to managing cloud projects, Cloud Computing Strategies provides the understanding required to evaluate the technology and determine how it can be best applied to improve business and enhance your overall corporate strategy. Based on extensive research, it examines the opportunities and challenges that loom in the cloud. It explains exactly what cloud computing is, what it has to offer, and calls attention to the important issues management needs to consider before passing the point of no return regarding financial commitments.

ATLAS Cloud R&D

Science.gov (United States)

Panitkin, Sergey; Barreiro Megino, Fernando; Caballero Bejar, Jose; Benjamin, Doug; Di Girolamo, Alessandro; Gable, Ian; Hendrix, Val; Hover, John; Kucharczyk, Katarzyna; Medrano Llamas, Ramon; Love, Peter; Ohman, Henrik; Paterson, Michael; Sobie, Randall; Taylor, Ryan; Walker, Rodney; Zaytsev, Alexander; Atlas Collaboration

2014-06-01

The computing model of the ATLAS experiment was designed around the concept of grid computing and, since the start of data taking, this model has proven very successful. However, new cloud computing technologies bring attractive features to improve the operations and elasticity of scientific distributed computing. ATLAS sees grid and cloud computing as complementary technologies that will coexist at different levels of resource abstraction, and two years ago created an R&D working group to investigate the different integration scenarios. The ATLAS Cloud Computing R&D has been able to demonstrate the feasibility of offloading work from grid to cloud sites and, as of today, is able to integrate transparently various cloud resources into the PanDA workload management system. The ATLAS Cloud Computing R&D is operating various PanDA queues on private and public resources and has provided several hundred thousand CPU days to the experiment. As a result, the ATLAS Cloud Computing R&D group has gained a significant insight into the cloud computing landscape and has identified points that still need to be addressed in order to fully utilize this technology. This contribution will explain the cloud integration models that are being evaluated and will discuss ATLAS' learning during the collaboration with leading commercial and academic cloud providers.

Architecture Design of Healthcare Software-as-a-Service Platform for Cloud-Based Clinical Decision Support Service

OpenAIRE

Oh, Sungyoung; Cha, Jieun; Ji, Myungkyu; Kang, Hyekyung; Kim, Seok; Heo, Eunyoung; Han, Jong Soo; Kang, Hyunggoo; Chae, Hoseok; Hwang, Hee; Yoo, Sooyoung

2015-01-01

Objectives To design a cloud computing-based Healthcare Software-as-a-Service (SaaS) Platform (HSP) for delivering healthcare information services with low cost, high clinical value, and high usability. Methods We analyzed the architecture requirements of an HSP, including the interface, business services, cloud SaaS, quality attributes, privacy and security, and multi-lingual capacity. For cloud-based SaaS services, we focused on Clinical Decision Service (CDS) content services, basic functi...

EXPERIENCE OF THE ORGANIZATION OF VIRTUAL LABORATORIES ON THE BASIS OF TECHNOLOGIES OF CLOUD COMPUTING

Directory of Open Access Journals (Sweden)

V. Oleksyuk

2014-06-01

Full Text Available The article investigated the concept of «virtual laboratory». This paper describes models of deploying of cloud technologies in IT infrastructure. The hybrid model is most recent for higher educational institution. The author suggests private cloud platforms to deploying the virtual laboratory. This paper describes the experience of the deployment enterprise cloud in IT infrastructure of Department of Physics and Mathematics of Ternopil V. Hnatyuk National Pedagogical University. The object of the research are virtual laboratories as components of IT infrastructure of higher education. The subject of the research are clouds as base of deployment of the virtual laboratories. Conclusions. The use of cloud technologies in the development virtual laboratories of the is an actual and need of the development. The hybrid model is the most appropriate in the deployment of cloud infrastructure of higher educational institution. It is reasonable to use the private (Cloudstack, Eucalyptus, OpenStack cloud platform in the universities.

On Cloud-based Oversubscription

OpenAIRE

Householder, Rachel; Arnold, Scott; Green, Robert

2014-01-01

Rising trends in the number of customers turning to the cloud for their computing needs has made effective resource allocation imperative for cloud service providers. In order to maximize profits and reduce waste, providers have started to explore the role of oversubscribing cloud resources. However, the benefits of cloud-based oversubscription are not without inherent risks. This paper attempts to unveil the incentives, risks, and techniques behind oversubscription in a cloud infrastructure....

Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part II: Multi-layered cloud

Energy Technology Data Exchange (ETDEWEB)

Morrison, H; McCoy, R B; Klein, S A; Xie, S; Luo, Y; Avramov, A; Chen, M; Cole, J; Falk, M; Foster, M; Genio, A D; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; McFarquhar, G; Poellot, M; Shipway, B; Shupe, M; Sud, Y; Turner, D; Veron, D; Walker, G; Wang, Z; Wolf, A; Xu, K; Yang, F; Zhang, G

2008-02-27

Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a deep, multi-layered, mixed-phase cloud system observed during the ARM Mixed-Phase Arctic Cloud Experiment. This cloud system was associated with strong surface turbulent sensible and latent heat fluxes as cold air flowed over the open Arctic Ocean, combined with a low pressure system that supplied moisture at mid-level. The simulations, performed by 13 single-column and 4 cloud-resolving models, generally overestimate the liquid water path and strongly underestimate the ice water path, although there is a large spread among the models. This finding is in contrast with results for the single-layer, low-level mixed-phase stratocumulus case in Part I of this study, as well as previous studies of shallow mixed-phase Arctic clouds, that showed an underprediction of liquid water path. The overestimate of liquid water path and underestimate of ice water path occur primarily when deeper mixed-phase clouds extending into the mid-troposphere were observed. These results suggest important differences in the ability of models to simulate Arctic mixed-phase clouds that are deep and multi-layered versus shallow and single-layered. In general, models with a more sophisticated, two-moment treatment of the cloud microphysics produce a somewhat smaller liquid water path that is closer to observations. The cloud-resolving models tend to produce a larger cloud fraction than the single-column models. The liquid water path and especially the cloud fraction have a large impact on the cloud radiative forcing at the surface, which is dominated by the longwave flux for this case.

CloudSat-Constrained Cloud Ice Water Path and Cloud Top Height Retrievals from MHS 157 and 183.3 GHz Radiances

Science.gov (United States)

Gong, J.; Wu, D. L.

2014-01-01

Ice water path (IWP) and cloud top height (ht) are two of the key variables in determining cloud radiative and thermodynamical properties in climate models. Large uncertainty remains among IWP measurements from satellite sensors, in large part due to the assumptions made for cloud microphysics in these retrievals. In this study, we develop a fast algorithm to retrieve IWP from the 157, 183.3+/-3 and 190.3 GHz radiances of the Microwave Humidity Sounder (MHS) such that the MHS cloud ice retrieval is consistent with CloudSat IWP measurements. This retrieval is obtained by constraining the empirical forward models between collocated and coincident measurements of CloudSat IWP and MHS cloud-induced radiance depression (Tcir) at these channels. The empirical forward model is represented by a lookup table (LUT) of Tcir-IWP relationships as a function of ht and the frequency channel.With ht simultaneously retrieved, the IWP is found to be more accurate. The useful range of the MHS IWP retrieval is between 0.5 and 10 kg/sq m, and agrees well with CloudSat in terms of the normalized probability density function (PDF). Compared to the empirical model, current operational radiative transfer models (RTMs) still have significant uncertainties in characterizing the observed Tcir-IWP relationships. Therefore, the empirical LUT method developed here remains an effective approach to retrieving ice cloud properties from the MHS-like microwave channels.