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1

Low level cloud motion vectors from Kalpana-1 visible images  

NASA Astrophysics Data System (ADS)

Till now low-level winds were retrieved using Kalpana-1 infrared (IR) images only. In this paper, an attempt has been made to retrieve low-level cloud motion vectors using Kalpana-1 visible (VIS) images at every half an hour. The VIS channel provides better detection of low level clouds, which remain obscure in thermal IR images due to poor thermal contrast. The tracers are taken to be 15 × 15 pixel templates and hence each wind corresponds to about 120 km × 120 km at sub-satellite point. Multiplet based wind retrieval technique is followed for VIS wind derivation. However, for height assignment of VIS winds, collocated IR image is used. Due to better contrast between cloud and ocean surface, the low level atmospheric flow is captured better as compared to IR winds. The validation of the derived VIS winds is done with Global Forecast System (GFS) model winds and Oceansat-II scatterometer (OSCAT) winds.

Kaur, Inderpreet; Deb, S. K.; Kishtawal, C. M.; Pal, P. K.; Kumar, Raj

2013-08-01

2

The MISR Cloud Motion Vector Product: 10 years of height resolved, cloud-track winds  

NASA Astrophysics Data System (ADS)

By utilizing multiple camera views and fast image matching algorithms to identify common features and determine feature motion, the MISR instrument on NASA’s Terra satellite has now collected 10 years of height-resolved, cloud-track, vector winds using a single, globally consistent algorithm. MISR cloud-track winds are packaged within the new MISR Cloud Motion Vector product, reported on mesoscale domains of 70.4 km × 70.4 km and referenced to stereoscopically derived heights above the earth ellipsoid with a nominal precision of 230 m. Importantly, from the standpoint of climate research, the stereo height assignment and wind retrieval are largely insensitive to instrument calibration changes and independent of a priori assumptions because the product algorithms depend only on patterns of observed brightness variability. We will describe comparisons with other wind observations, including geostationary cloud drift winds, raob winds, and scatterometer surface winds that demonstrate the quality of the MISR winds. We will also show the coverage and resolution advantages that MISR provides relative to these other datasets. Additionally, we will analyze agreement and discrepancies between MISR winds and reanalysis winds.

Mueller, K.; Garay, M. J.; Jovanovic, V.; Moroney, C.; Wu, D. L.; Diner, D. J.

2010-12-01

3

Macro motion vector quantization  

NASA Astrophysics Data System (ADS)

A new algorithm is developed for reducing the bit rate required for motion vectors. This algorithm is a generalization of block matching motion estimation in which the search region is represented as a codebook of motion vectors. The new algorithm, called macro motion vector quantization (MMVQ), generalized our earlier MVQ by coding a group of motion vectors. The codebook is a set of macro motion vectors which represent the block locations of the small neighboring blocks in the previous frame. We develop an interative design algorithm for the codebook. Our experiments show that the variances of displaced frame differences (DFDs) are reduced significantly compared to block matching algorithm (BMA) with the macroblock size.

Lee, Yoon Y.; Woods, John W.

1995-04-01

4

Reversing Motion Vector Fields  

Microsoft Academic Search

We examine the problem of estimating a reverse motionvector field from a given forward motion vector fieldand its motion-compensated residual. This problem haspractical importance when providing reverse-play functionalityin compressed video environments, where video data isstored, processed, and transported in compressed form. Wepresent a family of algorithms that trade off motion vectoraccuracy for computational efficiency. Experimental resultsdemonstrate the performance of these...

Susie J. Wee

1998-01-01

5

Error Estimation in deriving the Atmospheric Motion Vectors from cloud images  

Microsoft Academic Search

The primary goal of Japan's Venus meteorological satellite mission (Planet-C), which will be launched in 2007, is to reveal the formation and maintenance mechanism of high speed westward winds in the Venusian atmosphere called super-rotation (approximately 100 m\\/s at the altitude of 70 km). The mechanism to keep on transporting momentum from the surface to the cloud-top has been wrapped

T. Murachi; T. Imamura; T. Higuchi; M. Nakamura

2001-01-01

6

Cloud motion detection from infrared satellite images  

NASA Astrophysics Data System (ADS)

The estimation of cloud motion from a sequence of satellite images can be considered a challenging task due to the complexity of phenomena implied. Being a non-rigid motion and implying non-linear events, most motion models are not suitable and new algorithms have to be developed. We propose a novel technique, combining a Block Matching Algorithm (BMA) and a best candidate block search along with a vector median regularisation.

Brad, Remus; Letia, Ioan A.

2002-07-01

7

Operational Cloud-Motion Winds from Meteosat Infrared Images  

Microsoft Academic Search

The displacement of clouds in successive satellite images reflects the atmospheric circulation at various scales. The main application of the satellite-derived cloud-motion vectors is their use as winds in the data analysis for numerical weather prediction. At low latitudes in particular they constitute an indispensible data source for numerical weather prediction.This paper describes the operational method of deriving cloud-motion winds

Johannes Schmetz; Kenneth Holmlund; Joel Hoffman; Bernard Strauss; Brian Mason; Volker Gaertner; Arno Koch; Leo van de Berg

1993-01-01

8

Noctilucent Clouds in Motion  

NASA Video Gallery

Swedish photographer Peter Rosén took this close-up, time-lapse movie of Noctilucent Clouds (NLCs) over Stockholm, Sweden on the evening of July 16, 2012. "What looked like a serene view from a distance behaves more like a stormy sea with wave after wave rolling in," Rosen observes. › Read more about NLCs and the NASA AIM mission studying them.

Holly Zell

2012-07-18

9

Motion vector quantization for video coding.  

PubMed

A new algorithm is developed for the vector quantization of motion vectors. This algorithm, called motion vector quantization (MVQ), simultaneously estimates and vector quantizes the motion vectors by reinterpreting the block matching algorithm as a type of vector quantization. An iterative design algorithm, based on this concept, is developed. In addition to reducing rate for fixed length encoding, the algorithm also reduces the computation considerably. We include coding simulation results on the Flower Garden sequence. PMID:18289987

Lee, Y Y; Woods, J W

1995-01-01

10

Proper Motions of the Clouds  

NASA Astrophysics Data System (ADS)

We have measured the proper motion of the Large Magellanic Cloud (LMC) relative to background quasars, identified in three different regions of the Cloud, using CCD frames taken with the CTIO 1.5 m telescope. These regions are 3.9 , 4.1 and 5.9 degrees from the LMC center and at a position angle (equatorial system) of 64.3, 64.4 and 66.1 degrees. Observations were carried out between 1989 and 1996 at the cassegrain focus (f/13.5) of the telescope. The scale is 0.24"/pix using a Tektronic 1024 CCD, giving a field of view of 4x4 arcmin. Frames always were centered on the quasars. We measured the proper motion of the quasars with respect to LMC stars, which in reality, reflects the motion of the LMC stars. The standard deviation of the measurement of an image centroid is 3 mas; and the standard error of the mean position of a point-like object in a given epoch is 1.5 mas. After correcting for LMC rotation and different perspective we obtained mualphacos(delta) = +1.7 +/- 0.2 mas/yr and mudelta = +2.8 +/- 0.2 mas/yr as the proper motion components of the LMC center. Our mualphacos(delta) value is in good agreement with previous measurements using PPM catalogue data by Kroupa, Roeser and Bastian (1994), by Jones, Klemola and Lin (1994) using background galaxies in a field 8.5 degrees from the LMC center and by Kroupa and Bastian (1997) using data obtained with the Hipparcos satellite. In fact, Kroupa and Bastian (1997) give mualphacos(delta) = +1.61 +/- 0.19 mas/yr as the weighted mean of these three independent measurements. On the contrary, our mudelta measurement is too large compare with their value mudelta = -0.17 +/- 0.22 mas/yr. Our LMC proper motion 3.3 +/- 0.2 mas/yr, with the position angle of 31 degrees seams to indicate that the LMC is not leading the Magallanic Stream. CCD astrometry of SMC fields with background quasars will be important to clarify this disagreement.

Anguita, C.

11

Efficient motion-estimated vector quantizer  

NASA Astrophysics Data System (ADS)

In this paper, we have proposed an efficient motion estimated vector quantizer (MEVQ) which reduces the full searching time of the VQ encoder by means of motion estimation. In image sequence successive frames are usually very highly correlated. Using the frame difference we can classify a moving area and a static area in a frame. And by motion estimation we can get motion vectors for each block. In MEVQ we make two sets of codebooks. One is the main codebook which has all codewords and the other is the sub codebook which is a subset of the main codebook. For the static area MEVQ refers to the sub codebook instead of the main codebook. For motion parts that have motion vectors it refers to the sub codebook by the help of motion vectors. For the rest of the image frame that are moving areas but cannot have motion vectors it refers to the main codebook. According to our computer simulation, MEVQ reduces the searching time greatly compared with the normal full search VQ without any significant degradation.

Lee, Inseop; Kim, Jong G.; Ann, Souguil J.

1993-10-01

12

Volcanic explosion clouds - Density, temperature, and particle content estimates from cloud motion  

Microsoft Academic Search

Photographic records of 10 vulcanian eruption clouds produced during the 1978 eruption of Fuego Volcano in Guatemala have been analyzed to determine cloud velocity and acceleration at successive stages of expansion. Cloud motion is controlled by air drag (dominant during early, high-speed motion) and buoyancy (dominant during late motion when the cloud is convecting slowly). Cloud densities in the range

Lionel Wilson; Stephen Self

1980-01-01

13

Bayesian Estimation of Motion Vector Fields  

Microsoft Academic Search

This paper presents a new approach to the estimation of two-dimensional motion vectorfields from time-varying images. The approach is stochastic, both in its formulation andin the solution method. The formulation involves the specification of a deterministicstructural model, along with stochastic observation and motion field models. Two motionmodels are proposed: a globally smooth model based on vector Markov random fieldsand a

Janusz Konrad; Eric Dubois

1992-01-01

14

Using raw MPEG motion vectors to determine global camera motion  

NASA Astrophysics Data System (ADS)

This paper presents a simple and effective method to determine global camera motion using raw MPEG-1 motion vectors information obtained straight form real MPEG-1 streams such as those of the new HITACHI MP-EG1A digital camcorder. The simple approach we have experimented with robustly fits a global affine optic flow model to the motion vectors. Other more robust methods are also proposed. In order to cope with the group-of-frames (GOF) discontinuity of the MPEG stream, B frames are used backward to determine the 'missing link' to a previous GOF thereby ensuring continuity of the motion estimation across a reasonable number of frames. As a tested, we have applied the method to the image mosaicing problem, for which interesting results have been obtained. Although several other methods exists to perform camera motion estimation, the approach presented here is particularly interesting because exploits 'free' information present in MPEG streams and bypass the highly expensive correlation process.

Pilu, Maurizio

1998-01-01

15

Operational cloud-motion winds from Meteosat infrared images  

SciTech Connect

The displacements of clouds in successive satellite images reflects the atmospheric circulation at various scales. The main application of the satellite-derived cloud-motion vectors is their use as winds in the data analysis for numerical weather prediction. At low latitudes in particular they constitute an indispensible data source for numerical weather prediction. This paper describes the operational method of deriving cloud-motion winds (CMW) from the IR images (10.5-12.5 [mu]m) of the European geostationary Meteosat satellites. The method is automatic, that is, the cloud tracking uses cross correlation and the height assignment is based on satellite observed brightness temperature and a forecast temperature profile. Semitransparent clouds undergo a height correction based on radiative forward calculations and simultaneous radiance observations in both the IR and water vapor (5.7-7.1 [mu]m) channel. Cloud-motion winds are subject to various quality checks that include manual quality controls as the last step. Typically about 3000 wind vectors are produced per day over four production cycles. This paper documents algorithm changes and improvements made to the operational CMWs over the last five years. The improvements are shown by long-term comparisons with both collocated radiosondes and the first guess of the forecast model of the European Centre for Medium-Range Weather Forecasts. In particular, the height assignment of a wind vector and radiance filtering techniques preceding the cloud tracking have ameliorated the errors in Meteosat winds. The slow speed bias of high-level CMWs (<400 hPa) in comparison to radiosonde winds has been reduced from about 4 to 1.3 m s[sup [minus]1] for a mean wind speed of 24 m s[sup [minus]1]. Correspondingly, the rms vector error of Meteosat high-level CMWs decreased from about 7.8 to 5 m s[sup [minus]1]. Medium-and low-level CMWs were also significantly improved. 56 refs., 12 figs., 2 tabs.

Schmetz, J.; Holmlund, K.; Mason, B.; Gaertner, V.; Koch, A.; Van De Berg, L. (European Space Agency, Darmstadt (Germany)); Hoffman, J. (METEO France, Toulouse (France)); Strauss, B. (European Centre for Medium-Range Weather Forecasts, Berkshire (United Kingdom))

1993-07-01

16

Global motion estimation from coarsely sampled motion vector field and the applications  

Microsoft Academic Search

Global motion estimation is a powerful tool widely used in video processing and compression as well as in computer vision areas. We propose a new approach for estimating global motions from coarsely sampled motion vector fields. The proposed method minimizes the fitting error between the input motion vectors and the motion vectors generated from the estimated motion model using the

Yeping Su; Ming-ting Sun; Vincent Hsu

2005-01-01

17

Improved flicker removal through motion vectors compensation  

Microsoft Academic Search

Image flicker, the unnatural temporal fluctuation in perceived image intensity, is an annoying artifact existing in many old film sequences and its removal is an integral part in any old film restoration process. In this paper, we propose an improved flicker removal method based on flicker parameters estimation with the aide of motion vectors compensation. We tested the proposed method

K. K. Wong; A. Das; M. N. Chong

2004-01-01

18

New fast algorithms for the estimation of block motion vectors  

Microsoft Academic Search

Two algorithms for block motion estimation that produce performance similar to that of exhaustive search but with computation reduced by a factor of 8 or 16 are presented. The algorithms are based on motion-field and pixel subsampling. A subsampled motion field is first determined by estimating the motion vectors for a fraction of the blocks. The motion vectors for these

Bede Liu; Andre Zaccarin

1993-01-01

19

Motion/imagery secure cloud enterprise architecture analysis  

NASA Astrophysics Data System (ADS)

Cloud computing with storage virtualization and new service-oriented architectures brings a new perspective to the aspect of a distributed motion imagery and persistent surveillance enterprise. Our existing research is focused mainly on content management, distributed analytics, WAN distributed cloud networking performance issues of cloud based technologies. The potential of leveraging cloud based technologies for hosting motion imagery, imagery and analytics workflows for DOD and security applications is relatively unexplored. This paper will examine technologies for managing, storing, processing and disseminating motion imagery and imagery within a distributed network environment. Finally, we propose areas for future research in the area of distributed cloud content management enterprises.

DeLay, John L.

2012-05-01

20

Analysis of motion vector errors in motion compensated frame rate up conversion  

Microsoft Academic Search

Frame rate up conversion methods that employ motion have been proven to provide better image quality compared to nonmotion based methods. While motion based methods improve the performance of interpolation; artifacts are introduced in the presence of incorrect motion vectors. In this paper, the effect of motion vector errors on the efficiency of motion compensated frame rate up conversion (MC-FRUC)

GokGe Dane; Truong Q. Nguyen

2003-01-01

21

Structure and Nonrigid Motion Analysis of Satellite Cloud Images  

Microsoft Academic Search

This paper proposes a new method for recoveringnonrigid motion and structure of clouds under affineconstraints using time-varying cloud images obtainedfrom meteorological satellites. This problem is challengingnot only due to the correspondence problembut also due to the lack of depth cues in the 2D cloudimages (scaled orthographic projection). In this paper,affine motion is chosen as a suitable model forsmall local cloud

Lin Zhou; Chandra Kambhamettu

1998-01-01

22

Improvement of cardiac CT reconstruction using local motion vector fields.  

PubMed

The motion of the heart is a major challenge for cardiac imaging using CT. A novel approach to decrease motion blur and to improve the signal to noise ratio is motion compensated reconstruction which takes motion vector fields into account in order to correct motion. The presented work deals with the determination of local motion vector fields from high contrast objects and their utilization within motion compensated filtered back projection reconstruction. Image registration is applied during the quiescent cardiac phases. Temporal interpolation in parameter space is used in order to estimate motion during strong motion phases. The resulting motion vector fields are during image reconstruction. The method is assessed using a software phantom and several clinical cases for calcium scoring. As a criterion for reconstruction quality, calcium volume scores were derived from both, gated cardiac reconstruction and motion compensated reconstruction throughout the cardiac phases using low pitch helical cone beam CT acquisitions. The presented technique is a robust method to determine and utilize local motion vector fields. Motion compensated reconstruction using the derived motion vector fields leads to superior image quality compared to gated reconstruction. As a result, the gating window can be enlarged significantly, resulting in increased SNR, while reliable Hounsfield units are achieved due to the reduced level of motion artefacts. The enlargement of the gating window can be translated into reduced dose requirements. PMID:19097853

Schirra, Carsten Oliver; Bontus, Claas; van Stevendaal, Udo; Dössel, Olaf; Grass, Michael

2008-12-19

23

Clouds on Neptune: Motions, Evolution, and Structure.  

National Technical Information Service (NTIS)

The aims of our original proposal were these: (1) improving measurements of Neptune's circulation, (2) understanding the spatial distribution of cloud features, (3) discovery of new cloud features and understanding their evolutionary process, (4) understa...

L. A. Sromovsky

2001-01-01

24

Cloud motions on Venus - Global structure and organization  

Microsoft Academic Search

Results on cloud motions on Venus obtained over a period of 3.5 days from Mariner 10 television images are presented. The implied atmosphere flow is almost zonal everywhere on the visible disk, and is in the same retrograde sense as the solid planet. Objective analysis of motions suggests the presence of jet cores (-130 m\\/s) and organized atmospheric waves. The

Sanjay Shridhar Limaye; V. E. Suomi

1981-01-01

25

Recovery of lost or erroneously received motion vectors  

Microsoft Academic Search

A technique using boundary matching to compensate for lost or erroneously received motion vectors in motion-compensated video coding is proposed. This technique, called the boundary matching algorithm, produces noticeably better results than those reported previously. It is first assumed that the displaced frame differences have no error. Then, this assumption is relaxed by proposing an algorithm (the extended boundary matching

W. M. Lam; A. R. Reibman; B. Liu

1993-01-01

26

Vector Analysis of Human Limb Motion.  

ERIC Educational Resources Information Center

|Uses vectors to illustrate movement of the human appendicular structures to help students visualize the interaction of the various muscles and understand how a small number of muscles can affect movement in a potentially infinite number of directions. (ZWH)|

Laferriere, Joseph E.

1994-01-01

27

Vector quantization of 3-D point clouds  

NASA Astrophysics Data System (ADS)

A geometry compression algorithm for 3-D QSplat data using vector quantization (VQ) is proposed in this work. The positions of child spheres are transformed to the local coordinate system, which is determined by the parent children relationship. The coordinate transform makes child positions more compactly distributed in 3-D space, facilitating effective quantization. Moreover, we develop a constrained encoding method for sphere radii, which guarantees hole-free surface rendering at the decoder side. Simulation results show that the proposed algorithm provides a faithful rendering quality even at low bitrates.

Sim, Jae-Young; Kim, Chang-Su; Lee, Sang-Uk

2005-10-01

28

Predictive motion vector field adaptive search technique (PMVFAST): enhancing block-based motion estimation  

Microsoft Academic Search

Motion Estimation (ME) is an important part of most video encoding systems, since it could significantly affect the output quality of an encoded sequence. Unfortunately this feature requires a significant part of the encoding time especially when using the straightforward Full Search (FS) algorithm. In this paper a new algorithm is presented named as the Predictive Motion Vector Field Adaptive

Alexis M. Tourapis; Oscar C. Au; Ming L. Liou

2001-01-01

29

The role of the harmonic vector average in motion integration  

PubMed Central

The local speeds of object contours vary systematically with the cosine of the angle between the normal component of the local velocity and the global object motion direction. An array of Gabor elements whose speed changes with local spatial orientation in accordance with this pattern can appear to move as a single surface. The apparent direction of motion of plaids and Gabor arrays has variously been proposed to result from feature tracking, vector addition and vector averaging in addition to the geometrically correct global velocity as indicated by the intersection of constraints (IOC) solution. Here a new combination rule, the harmonic vector average (HVA), is introduced, as well as a new algorithm for computing the IOC solution. The vector sum can be discounted as an integration strategy as it increases with the number of elements. The vector average over local vectors that vary in direction always provides an underestimate of the true global speed. The HVA, however, provides the correct global speed and direction for an unbiased sample of local velocities with respect to the global motion direction, as is the case for a simple closed contour. The HVA over biased samples provides an aggregate velocity estimate that can still be combined through an IOC computation to give an accurate estimate of the global velocity, which is not true of the vector average. Psychophysical results for type II Gabor arrays show perceived direction and speed falls close to the IOC direction for Gabor arrays having a wide range of orientations but the IOC prediction fails as the mean orientation shifts away from the global motion direction and the orientation range narrows. In this case perceived velocity generally defaults to the HVA.

Johnston, Alan; Scarfe, Peter

2013-01-01

30

Motion Vector Estimation of Video Image by Pyramidal Implementation of Lucas Kanade Optical Flow  

Microsoft Academic Search

Motion vector estimation is an important parameter for video segmentation. Effective video compression can be achieved by choosing a correct approach for the calculation of motion vector. Here in this paper we propose an optical flow motion vector estimation through iterative Lucas-Kanade pyramidal implementation for both large & small motion in image pyramid representation a group of pixel information is

Sukeshni N. Tamgade; Vibha R. Bora

2009-01-01

31

A new stereo object tracking system using disparity motion vector  

Microsoft Academic Search

In this paper, a new stereo object tracking system using the disparity motion vector (DMV) is presented. In the proposed method, the time-sequential disparity maps are extracted from the sequence of the stereo input image pairs and then, the DMV defined as a disparity difference between two consecutive disparity maps is sequentially estimated from these disparity maps. Just like the

Kyung-Hoon Bae; Jung-Sik Koo; Eun-Soo Kim

2003-01-01

32

Fluid Structure and Motion Analysis from Multi-spectrum 2D Cloud Image Sequences  

Microsoft Academic Search

In this paper we present a novel approach to estimateand analyze 3D fluid structure and motion ofclouds from multi-spectrum 2D cloud image sequences.Accurate cloud-top structure and motion are very importantfor a host of meteorological and climate applications.However, due to the extremely complex natureof cloud fluid motion, classical nonrigid motion analysismethods will be insufficient to solve this particularproblem. In this paper,

Lin Zhou; Chandra Kambhamettu; Dmitry B. Goldgof

2000-01-01

33

Automatically locating the typhoon center based on satellite cloud image  

Microsoft Academic Search

An automatic locating algorithm is presented for typhoon center locating using cloud motion wind vectors derived from the satellite cloud images. The cloud motion wind vectors are obtained by implementing template matching to a pair of interrelated satellite cloud images with stated time interval. The template matching is a process to find the child image that corresponds to the given

Zhengguang Liu; Juntao Xue; Yuanfei Yu; Bing Wu; Gary Shen

2004-01-01

34

10 Years of Height Resolved, Cloud-Track, Vector Winds from MISR  

NASA Astrophysics Data System (ADS)

By utilizing multiple camera views and fast image matching algorithms to identify common features and determine feature motion, the MISR instrument on NASA’s Terra satellite has now collected nearly 10 years of height-resolved, cloud-track, vector winds using a single, globally consistent algorithm. The MISR cloud-track winds are reported globally on mesoscale domains of 70.4 km × 70.4 km and referenced to stereoscopically derived heights above the earth ellipsoid, which have a nominal vertical resolution of approximately 500 m. Importantly, from the standpoint of climate research, the stereo height assignment and wind retrieval are largely insensitive to instrument calibration changes because the pattern matcher relies only on relative brightness values, rather than the absolute magnitude of the brightness. We will describe comparisons with other wind datasets, including geostationary cloud drift winds, scatterometer surface winds, and reanalysis model winds, that demonstrate the quality of the MISR winds. We will also show the coverage and resolution advantages that MISR provides relative to these other datasets. Additionally, because the global winds are driven primarily by the global (im)balance of heating, monitoring variations in the winds over 10 years promises to yield important insights into the processes related to the hydrologic cycle and transport of heat and water vapor, such as the Madden-Julian Oscillation (MJO) and the El Niño Southern Oscillation (ENSO).

Garay, M. J.; Mueller, K. J.; Moroney, C. M.; Jovanovic, V.; Wu, D. L.; Diner, D. J.

2009-12-01

35

A new stereo object tracking system using disparity motion vector  

NASA Astrophysics Data System (ADS)

In this paper, a new stereo object tracking system using the disparity motion vector (DMV) is presented. In the proposed method, the time-sequential disparity maps are extracted from the sequence of the stereo input image pairs and then, the DMV defined as a disparity difference between two consecutive disparity maps is sequentially estimated from these disparity maps. Just like the motion vectors in the conventional video signals, the DMV provides us with motion information of a moving target by showing a relatively large change of the disparity values in the target areas. Accordingly, using this DMV the target area and its location coordinates can be detected. Basing on these locational data of a moving target, the pan/tilt embedded in the stereo camera system can be controlled and as a result, real-time stereo tracking of a moving target can be achieved. From some experiments with 9 frames of the stereo image pairs having 256×256 pixels, it is shown that the proposed DMV-based stereo object tracking system can track the moving target with a relatively low error ratio of about 3.05% on average.

Bae, Kyung-Hoon; Koo, Jung-Sik; Kim, Eun-Soo

2003-06-01

36

Feature Tracking for Mobile Augmented Reality Using Video Coder Motion Vectors  

Microsoft Academic Search

We propose a novel, low-complexity, tracking scheme that uses motion vectors directly from a video coder. We compare our tracking algorithm against ground truth data, and show that we can achieve a high level of accuracy, even though the motion vectors are rate-distortion optimized and do not represent true motion. We develop a framework for tracking in video sequences with

Gabriel Takacs; Vijay Chandrasekhar; Bernd Girod; Radek Grzeszczuk

2007-01-01

37

Robust transmission of video sequence using double-vector motion compensation  

Microsoft Academic Search

This paper proposes a motion compensation (MC) algorithm for robust transmission of video sequence, called the double-vector motion compensation (DMC). In the DMC, each block B in a frame is predicted from the weighted superposition of two blocks in the previous two frames, using two motion vectors. Therefore, when one of these two blocks is corrupted during the transmission, the

Chang-su Kim; Rin-chul Kim; Sang-Uk Lee

2001-01-01

38

Object Tracking Algorithm Based on Meanshift Algorithm Combining with Motion Vector Analysis  

Microsoft Academic Search

Mean shift algorithm doesn't use the targetpsilas motion direction and speed information in process of object tracking. When the targetpsilas speed is so fast it easily fails to track the target. So a new object tracking algorithm combining Mean shift algorithm with Motion Vector analysis is proposed in this paper. By statistical analysis of the motion vector get from video

Tian Gang; Hu Rui-Min; Wang Zhong-Yuan; Zhu Li

2009-01-01

39

Proper Motions of the Large Magellanic Cloud and Small Magellanic Cloud: Re-Analysis of Hubble Space Telescope Data  

Microsoft Academic Search

Kallivayalil et al. have used the Hubble Space Telescope to measure proper motions of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) using images in 21 and five fields, respectively, all centered on known quasi-stellar objects (QSOs). These results are more precise than previous measurements, but have surprising and important physical implications: for example, the LMC and SMC

Slawomir Piatek; Carlton Pryor; Edward W. Olszewski

2008-01-01

40

Clouds  

NSDL National Science Digital Library

First, the Project Atmosphere Canada offers a module to educate primary and secondary students about cloud formation and characteristics (1). The website outlines key points and offers a more in-depth discussion of water vapor, cloud formation, convection, air motion, severe weather, and more. The second website, by Scholastic, supplies many pdf documents of activities and lesson plans for all types of weather phenomena including clouds (2). Students can learn about condensation, discover what makes up a cloud, and find a key identifying the cloud types. Next, USA Today offers an online tutorial of the differing characteristics of clouds (3). Users can learn about Mammatus clouds, contrails, cloud seeding, and other cloud-related topics. At the fourth website, visitors can view meteorologist Dan Satterfield's amazing cloud photographs (4). Educators may find useful materials to supplement their lectures. Next, NASA's Climate and Radiation Branch furnishes "information on the fantastic variety of cloud forms and structures, and their implications for climate" (5). While the website is still being constructed, users can find useful information about the Bounded Cascades Fractal Cloud model, animations, and definitions of inhomogeneous cloud terminology. The sixth website, created by the National Center for Atmospheric Research and the University Corporation for Atmospheric Research, addresses how clouds impact our lives, how they cause chaos, and how they form (6). The enlightening descriptions are packed with colorful images and short quizzes. Next, The Australian Government's Bureau of Meteorology describes the useful of clouds as an indicator of weather conditions (7). After learning how moist air can form clouds, individuals can view images of the ten most common cloud types. Lastly, Enchanted Learning offers a table of the cloud types with their abbreviation, appearance, composition, and altitude along with explanations of cloud formation and the atmosphere (8). Educators can find simple activities dealing with cloud types and the water cycle.

41

Spacelike Ricci inheritance vectors in a model of string cloud and string fluid stress tensor  

NASA Astrophysics Data System (ADS)

We study the consequences of the existence of spacelike Ricci inheritance vectors (SpRIVs) parallel to xa for a model of string cloud and string fluid stress tensor in the context of general relativity. Necessary and sufficient conditions are derived for a spacetime with a model of string cloud and string fluid stress tensor to admit a SpRIV, and a SpRIV which is also a spacelike conformal Killing vector. Also, some results are obtained.

Baysal, Hüsnü; Yilmaz, Ihsan

2002-12-01

42

A Method of Measuring the Axial Secular Motion Temperature of Trapping Large Size Ion Clouds  

NASA Astrophysics Data System (ADS)

A large cloud of 40Ca+ is successfully trapped and manipulated in a linear ion trap. The axial length of the ion cloud is measured under a series of end-cap voltages. We propose a method of measuring the axial secular motion temperature of the ion cloud by analyzing its image on an electron-multiplying CCD. The method is based on the Boltzmann equation that the axial density distribution of ions at secular motion temperature T satisfies. The axial secular motion temperature of the ion cloud is also obtained by measuring the Doppler broadened line width. For the same trapping parameters, the axial secular motion temperature by analyzing the image of ion cloud is 840 K and by fitting the experimental resonance line profile is 700 K.

Yang, Yu-Na; Liu, Hao; He, Yue-Hong; Li, Hai-Xia; Chen, Yi-He; She, Lei; Chen, Liang; Li, Jiao-Mei

2013-03-01

43

An independent motion and disparity vector prediction method for multiview video coding  

NASA Astrophysics Data System (ADS)

The inter-view prediction is used as well as the temporal prediction in order to exploit both the temporal and inter-view redundancies in multiview video coding. Accordingly, the multiview video coding has two types of motion vectors that are the temporal motion vector and the disparity vector, respectively. The disparity vector is generally uncorrelated with the temporal motion vector. However, they are used together to predict the motion vector regardless of their types, therefore an efficiency of the conventional predictive coding of multiview video coding is decreased. In order to increase the accuracy of the predicted motion vector, a new motion vector prediction method including virtual temporal motion vector and virtual disparity vector is proposed for both the multiview video and multiview video plus depth formats. The experimental results show that the proposed method can reduce the coding bitrates by 6.5% in average and 14.6% at maximum in terms of Bjontegaard metric compared to the conventional method.

Ryu, Seungchul; Seo, Jungdong; Kim, Dong Hyun; Lee, Jin Young; Wey, Ho-Cheon; Sohn, Kwanghoon

2012-02-01

44

Implications of Nonthermal Motions for Statistics of Lyman-Alpha Forest Clouds  

Microsoft Academic Search

We investigate the effects of nonthermal bulk motions within Lyalpha forest clouds on some observationally derived statistics of these clouds. We calculate the absorption-line profiles and curves of growth for three illustrative cases of single-peaked, non-Maxwellian velocity distributions. We then calculate the distributions in H I column density f(N) and velocity dispersion f(o) for Lyalpha forest clouds, using the corresponding

Varsha P. Kulkarni; S. Michael Fall

1995-01-01

45

Feasibility and Error Analysis of Cloud Motion Wind Extraction from Near-Simultaneous Multiangle MISR Measurements  

Microsoft Academic Search

Satellite wind measurements represent an invaluable contribution to the description of the flow field over the oceans. Conventional cloud-tracking techniques suffer from the inability to simultaneously determine wind speed and height. Currently, the uncertainty in the independently calculated heights is the major factor limiting the accuracy of cloud motion winds. Near-simultaneous multiangle imagery from the multiangle imaging spectro- radiometer (MISR)

Ákos Horváth; Roger Davies

2001-01-01

46

Vector field interpolation for cardiac motion compensated reconstruction  

Microsoft Academic Search

Cardiac CT image reconstruction suffers from motion artifacts due to heart motion during acquisition. In order to mitigate these effects, it is common practice to acquire with fast gantry rotation and do gated reconstruction. In addition, it is possible to estimate heart motion retrospectively and to incorporate that information in a motion compensated reconstruction (MCR). However, if shape tracking algorithms

Peter Forthmann; Udo van Stevendaal; Michael Grass; Thomas Koohler

2008-01-01

47

Vector velocity profiles of the solar wind within expanding magnetic clouds at 1 AU: Some surprises  

NASA Astrophysics Data System (ADS)

We investigated the average vector velocity profile of 36 carefully chosen WIND interplanetary magnetic clouds occurring over about a 7 year period since spacecraft launch, to see if a differential pattern of solar wind flow exists. Particular cases were chosen of clouds whose axes were generally within 45 degrees of the ecliptic plane and of relatively well determined characteristics obtained from cloud-parameter (cylindrically symmetric force free) fitting. This study was motivated by the desire to understand the manner in which magnetic clouds expand, a well know phenomenon revealed by most cloud speed-profiles at 1 AU. One unexpected and major result was that, even though cloud expansion was confirmed, it was primarily along the Xgse axis; i.e., neither the Ygse or Zgse velocity components reveal any noteworthy pattern. After splitting the full set of clouds into a north-passing set (spacecraft passing above the cloud, where Nn = 21) and south-passing set (Ns = 15), to study the plasma expansion of the clouds with respect to the position of the observer, it was seen that the Xgse component of velocity differs for these two sets in a rather uniform and measurable way for most of the average cloud's extent. This does not appear to be the case for the Ygse or Zgse velocity components where little measurable differences exists, and clearly no pattern, across the average cloud between the north and south positions. It is not clear why such a remarkably non-axisymmetric plasma flow pattern within the "average magnetic cloud" at 1 AU should exist. The study continues from the perspective of magnetic cloud coordinate representation. ~ ~ ~

Wu, C.; Lepping, R. P.; Berdichevsky, D.; Ferguson, T.; Lazarus, A. J.

2002-12-01

48

Tracking Nonrigid Motion and Structure from 2D Satellite Cloud Images without Correspondences  

Microsoft Academic Search

Tracking both structure and motion of nonrigid objects from monocular images is an important problem in vision. In this paper, a hierarchical method which integrates local analysis (that recovers small details) and global analysis (that appropriately limits possible nonrigid behaviors) is developed to recover dense depth values and nonrigid motion from a sequence of 2D satellite cloud images without any

Lin Zhou; Chandra Kambhamettu; Dmitry B. Goldgof; Kannappan Palaniappan; Frederick Hasler

2001-01-01

49

Cloud Water: An Important Vector of Atmospheric Deposition.  

National Technical Information Service (NTIS)

Because advective fogs are wind-borne, they not only wet vegetation, but can deliver large amounts of water and dissolved ions to the earth's surface. Previous efforts to measure cloud and fog water deposition are reviewed, and current studies are summari...

G. M. Lovett W. A. Reiners

1982-01-01

50

Modeling of satellite borne TDI CCD pitching imaging image motion velocity vector  

Microsoft Academic Search

In order to obtain three-dimensional observation effect with single satellite borne time delay and integrate charge coupled device (TDI-CCD), pitching imaging is required. More accurate real-time image motion velocity vector computational model of space camera is also necessary to make the imaging perfect. Imaging motion velocity vector computation model must be set up on image plane at pitching imaging. According

Liu Zhang; Shujun Li; Guang Jin; Xiubin Yang

2009-01-01

51

Typhoon cloud system segmentation with multichannel images using vector-valued Chan-Vese model  

NASA Astrophysics Data System (ADS)

Cloud segmentation is an important step and a very difficult problem in typhoon image processing. There are many works on cloud image segmentation, but few are carried out on typhoon primary cloud system (galaxy) segmentation. Typhoon satellite images are always multiple channels whose properties are very different, so that the appearances of these channels are different as well. In order to segment out primary cloud systems accurately, multiple channel images are employed in this paper. The image data is from MERSI (short for MEdium Resolution Spectral Imager) of Chinese FY- 3A meteorological satellite launched on March, 2008. The scalar multiphase Chan-Vese (CV) model is extended for the vector-valued images, so as to partition out typhoon cloud systems. The experiment results show that the multi-channel segmentation is more accurate, more complete and more effective than that of usually using only one image, with multiple channel images being treated as a vector one input into the CV model. The multi-channel segmentation integrates the distribution information of cloud systems in all channels, so information fusion of multiple channels are realized when segmenting.

Wei, Kun; Li, Yuanxiang; Jing, Zhongliang; Shi, Chunxiang

2009-10-01

52

PROPER-MOTION STUDY OF THE MAGELLANIC CLOUDS USING SPM MATERIAL  

SciTech Connect

Absolute proper motions are determined for stars and galaxies to V = 17.5 over a 450 deg{sup 2} area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program, which span a baseline of 40 years. Multiple, local relative proper-motion measures are combined in an overlap solution using photometrically selected Galactic disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC); ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}){sub LMC} = (1.89, + 0.39) {+-} (0.27, 0.27) masyr{sup -1} and ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}){sub SMC} = (0.98, - 1.01) {+-} (0.30, 0.29) masyr{sup -1}. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A dominant portion (0.25 mas yr{sup -1}) of the formal errors is due to the estimated uncertainty in the inertial system of the Hipparcos Catalog stars used to anchor the bright end of our proper motion measures. A more precise determination can be made for the proper motion of the SMC relative to the LMC; ({mu}{sub {alpha}cos {delta}}, {mu}{sub {delta}}){sub SMC-LMC} = (-0.91, - 1.49) {+-} (0.16, 0.15) masyr{sup -1}. This differential value is combined with measurements of the proper motion of the LMC taken from the literature to produce new absolute proper-motion determinations for the SMC, as well as an estimate of the total velocity difference of the two clouds to within {+-}54 km s{sup -1}. The absolute proper-motion results are consistent with the Clouds' orbits being marginally bound to the Milky Way, albeit on an elongated orbit. The inferred relative velocity between the Clouds places them near their binding energy limit and, thus, no definitive conclusion can be made as to whether or not the Clouds are bound to one another.

Vieira, Katherine; Girard, Terrence M.; Van Altena, William F.; Casetti-Dinescu, Dana I.; Korchagin, Vladimir I.; Herrera, David, E-mail: kvieira@cida.v, E-mail: terry.girard@yale.ed, E-mail: william.vanaltena@yale.ed [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

2010-12-15

53

Application of support vector machines in cloud detection using EOS/MODIS  

NASA Astrophysics Data System (ADS)

Focused on the cloud detection task using EOS/MODIS information, this paper introduced a new method of cloud detection by use of the Support Vector Machines (SVMs) algorithm. The performance of SVMs was compared with the prevailing method of BP neural network (BP-NN) method with different training set numbers. The two methods show similar detection accuracy when the training set number is larger (with a number larger than 1500), while SVMs perform better than BP-NN method when the sampling number is small (with a number of 250 or less). SVMs method was then used to detect cloud over both land and sea; it distinguished cloud from snow cover, water body, and other land surface objectives clearly. Therefore, the SVMs technique is proved effective as compared with traditional methods in remote sensing image classification and is worthwhile to be popularized in the society of remote sensing applications.

Wang, Hanjie; He, Yinming; Guan, Hao

2008-08-01

54

Adaptively weighted vector-median filters for motion-fields smoothing  

Microsoft Academic Search

In the field of video coding the issues of backward prediction and standards conversion have focused an increasing attention towards techniques for an effective estimation of the true interframe motion. The problem of restoration of motion vector-fields computed by means of a standard block matching algorithm is addressed. The restoration must be carried out carefully by exploiting both the spatial

L. Alparone; M. Barni; F. Bartolini; V. Cappellini

1996-01-01

55

Cloud field classification based upon high spatial resolution textural features. 2. Simplified vector approaches  

NASA Astrophysics Data System (ADS)

The huge volume of data being collected in global climate studies makes it necessary to develop efficient automatic data analysis methods. While most cloud classification algorithms are based upon multispectral signatures, there is growing use of textural features. The results given in Part 1 of this study demonstrate that textural features computed from the Gray Level Cooccurrence Matrix (GLCM) approach produce high cloud classification accuracies. The present study compares classification results derived from two vector approaches, Sum and Difference Histogram (SADH) and Gray Level Difference Vector (GLDV), with those from the GLCM approach. It is found that the SADH approach produces accuracies equivalent to those obtained using GLCM, but with greater ability to resolve error clusters; also, there is a 30% savings in run time and a 50% savings in storage requirements. The GLDV approach suffers a slight degradation in classification accuracy but has a 40% savings in run time and an 87% savings in storage requirements. Textural features are not highly sensitive to moderate variations in cloud threshold selection. However, the whole cloud, rather than only the brightest portions of the cloud, produce the highest classification accuracies. A very important result is that spatial information content and classification accuracy are preserved even at lower radiometric resolutions with effective gray levels of 16. means that significantly low resolution digitized versions of satellite imagery retain essentially the full spatial information content of the original digital data. Substitution of digitized imagery can significantly reduce the expense of many remote sensing studies.

Chen, D. W.; Sengupta, S. K.; Welch, R. M.

1989-10-01

56

University Navstar Consortium GPS Site Motion Vector/Crustal Velocity Archive  

NSDL National Science Digital Library

The University Navstar Consortium (UNAVCO) Boulder facility has developed a Global Positioning System (GPS) Site Motion Vector Archive. Precise motions of points on the Earth, made with continuous or episodic GPS measurements, are being used to study tectonic processes including plate motions, plate boundary zone deformation, earthquakes, and volcanic eruptions. This archive of GPS velocities contains project information, maps, links, data, and metadata from both regional and global GPS analyses and showcases the work conducted by university and other research investigators. The archive also contains a global plate motion model velocity calculator and an interactive map tool. Velocity data are also accessible via a Distributed Ocean Data Sets (DODS) server.

Meertens, Charles

2001-03-23

57

Adaptive quarter-pel motion estimation and motion vector coding algorithm for the H.264/AVC standard  

NASA Astrophysics Data System (ADS)

We present an adaptive quarter-pel (Qpel) motion estimation (ME) method for H.264/AVC. Instead of applying Qpel ME to all macroblocks (MBs), the proposed method selectively performs Qpel ME in an MB level. In order to reduce the bit rate, we also propose a motion vector (MV) encoding technique that adaptively selects a different variable length coding (VLC) table according to the accuracy of the MV. Experimental results show that the proposed method can achieve about 3% average bit rate reduction.

Jung, Seung-Won; Park, Chun-Su; Ha, Le Thanh; Ko, Sung-Jea

2009-11-01

58

Cometary cloud in the solar system and the Resibois--Prigogine singular invariants of motion  

SciTech Connect

A relation between nonintegrability of nonlinear dynamical systems with a continuous Fourier spectrum and irreversibility is investigated in terms of the Lie-algebraic formalism. Resibois and Prigogine's singular invariants of motion play an essential role. As an application of the formalism, we solve the restricted three-body problem for the case of nearly parabolic motion of the third body. This gives a model of the motion of a comet in the solar system. The results indicate that there is (deterministic) chaos in the motion of a comet in a nearly parabolic orbit. A possible physical implication of the chaotic motion is the existence of a cometary cloud surrounding the solar system. The theoretical results are compared with numerical results, and show good agreement.

Petrosky, T.Y.

1987-09-01

59

Multiangle Remote Sensing of Optically Thin Cirrus Clouds From MISR Using Support Vector Machines  

NASA Astrophysics Data System (ADS)

Thin cirrus clouds, those with optical depths less than 1, can potentially have large radiative effects on the atmospheric and surface energy budgets in regions where they are prevalent. They also present an impediment to the retrieval of clear sky properties such as aerosol optical depth, temperature profiles, etc. Such clouds, however, are notoriously difficult to detect using standard satellite remote sensing techniques. The unique multiangle sensing capability of the Multiangle Imaging SpectroRadiometer (MISR) on NASA's Terra satellite, in particular the availability of cameras with view angles as large as 70.5 degrees, gives MISR the ability to detect thin cirrus clouds that are invisible to nadir-looking instruments. While MISR has been operational for over four years and many scenes containing thin cirrus have been examined on a per case basis, there remains a need to objectively and automatically identify just the cirrus clouds within any given scene. Based on our previous work applying machine learning technology to develop a more robust MISR cloud mask, we have developed a thin cirrus cloud detector for MISR, using Support Vector Machines (SVMs), and taking advantage of spectral, spatial and angular signature information from MISR's 45.6, 60 and 70.5-degree cameras. For a few representative cases, we will demonstrate the accuracy of the SVM cirrus retrieval, especially in comparison to a traditional nadir-looking retrieval, emphasizing the usefulness of the multiangle approach. We then show how this trained SVM can be used to generate a climatology of thin cirrus clouds.

Garay, M. J.; Mazzoni, D.; Davies, R.; Wagstaff, K.

2004-05-01

60

The Systemic Proper Motions of the Magellanic Clouds and their Orbits around the Milky Way  

NASA Astrophysics Data System (ADS)

The interaction between the Large and Small Magellanic Clouds (LMC & SMC) and the Milky Way (MW) is thought to have played an important role in the dynamical evolution of the MW's outer parts. The Clouds probe the potential of the MW dark halo in places where other kinematic tracers are unavailable and thus the MW-MC system has been a major subject of study. In particular, the global dynamics of both Clouds need to be well prescribed before other evolutionary features of the system can be understood. The radial velocities of the clouds are more readily determined than the transverse velocities, which can only be estimated using proper motions. We undertook a project using two epochs of HST/ACS data to determine the systemic proper motions of the Clouds. The Magellanic Cloud fields are centered on background QSOs that were discovered from their optical variability in the MACHO database (Geha et al. 2003). The final sample consists of 21 QSOs behind the LMC and 5 behind the SMC, distributed homogeneously behind the central few degrees of both Clouds. With a ˜2 year baseline and the use of the High Resolution Camera, we have determined the proper motion of the LMC to better than 5 \\ ? N = 0.44 ± 0.05 mas/yr (Kallivayalil et al. 2005). This is the most accurate proper motion measurement for any MW satellite thus far. We will present this measurement, as well as our results for the SMC, and the conclusions we can draw about the Clouds' orbits around the MW. Our study shows that ground-based work on finding QSOs can be combined with high resolution HST data to get good measurements in a relatively short amount of time. When combined with HI data from the Magellanic Stream our measurements should provide new constraints on both the mass distribution of the Galactic Halo and models of the Stream. Support for this work was provided by NASA through grant numbers GO-09462 and GO-10130 from STScI. KHC's work was performed under the auspices of the U.S. DOE, NNSA, by the Univ. of California, LLNL under contract No. W-7405-Eng-48.

Kallivayalil, N.; van der Marel, R. P.; Alcock, C.; Axelrod, T.; Cook, K. H.; Drake, A. J.; Geha, M.

2005-12-01

61

A CMOS image sensor for focal-plane low-power motion vector estimation  

Microsoft Academic Search

This paper presents a CMOS image sensor which captures intermediate pictures at 480 frames\\/s and a fully accumulated picture at 30 frames\\/s. The CMOS image sensor is for integrating a low-power motion vector estimation (MVE) engine using the iterative block matching algorithm proposed by the authors

D. Handoko; S. Kawahito; Y. Takokoro; M. Kumahara; A. Matsuzawa

2000-01-01

62

The motions of the Magellanic Clouds and the nature of galactic dark matter  

NASA Astrophysics Data System (ADS)

I present a measurement of the systemic proper motions of the Large & Small Magellanic Clouds (LMC & SMC) made using the Advanced Camera for Surveys on the Hubble Space Telescope . We tracked the LMC's(SMC's) motion relative to 21(5) background QSOs over a baseline of approximately 2 years. The measured proper motion for the LMC is accurate to better than 5%: m W = -2.03 ± 0.08 mas yr - 1 , m N = 0.44 ± 0.05 mas yr -1 , while that for the SMC is accurate to 15%: m W = -1.16 ± 0.18 mas yr -1 , m N = -1.17 ± 0.18 mas yr -1 . This is a 7(4)-fold improvement over previous measurements for the LMC(SMC), and is sufficient to provide improved constraints on the properties of the Milky Way (MW) dark halo. The current relative velocity between the Clouds, 105 ± 42 km s -1 , is substantially higher than that used in theoretical models of the Magellanic Stream. Investigations of the past orbital motions of the Clouds in an isothermal model for the dark halo of the MW imply that the Clouds could be coincidental companions, unbound from each other. However, bound orbits are also found within our error circles. Smaller proper motion errors and better understanding of L/SMC masses would be required to constrain their bound vs. unbound nature unambiguously. The absolute velocities of the Clouds are also substantially higher (~ 100 km s -1 ) than those used in models. Consequently, in a LCDM-motivated MW model ( M vir = 10 12 [Special characters omitted. ] ), we find that the Clouds are likely only on their first passage, which would require a major reassessment of formation mechanisms for the Magellanic Stream. Alternatively, the MW dark halo must be more massive than presently believed, M vir > 2 x 10 12 [Special characters omitted.] , which may conflict with other observational constraints. I also investigate MW structure via microlensing. We have used the Infrared Array Camera (IRAC) on the Spitzer Space Telescope to obtain near/mid-infrared imaging for 15 LMC microlensing events seen in the original MACHO survey to characterize the lensing population. This has resulted in the identification of two MACHO lenses, via their infrared excesses, as M dwarfs in the MW disk. These are the only two microlenses identified to date. Together, they are still consistent with the expected frequency of nearby stars in the MW thin and thick disks acting as lenses. I discuss the region of phase- space in terms of distance and magnitude that can be probed with IRAC, and hence what the results mean for the microlensing population in general.

Kallivayalil, Nitya Jacob

2007-08-01

63

Strange Quark Matter Attached to the String Cloud in the Spherical Symmetric Space-Time Admitting Conformal Motion  

NASA Astrophysics Data System (ADS)

In this paper, we have examined charged strange quark matter attached to the string cloud in the spherical symmetric space-time admitting one-parameter group of conformal motions. For this purpose, we have solved Einstein's field equations for spherical symmetric space-time with strange quark matter attached to the string cloud via conformal motions. Also, we have discussed the features of the obtained solutions.

Yavuz, Ilhami; Yilmaz, Ihsan; Baysal, Hüsnü

64

Strange Quark Matter Attached to the String Cloud in the Spherical Symmetric Space-Time Admitting Conformal Motion  

Microsoft Academic Search

In this paper, we have examined charged strange quark matter attached to the string cloud in the spherical symmetric space-time admitting one-parameter group of conformal motions. For this purpose, we have solved Einstein's field equations for spherical symmetric space-time with strange quark matter attached to the string cloud via conformal motions. Also, we have discussed the features of the obtained

Ilhami Yavuz; Ihsan Yilmaz; Hüsnü Baysal

2005-01-01

65

Very large scale integration (VLSI) architecture for motion estimation and vector quantization  

NASA Astrophysics Data System (ADS)

A hardware design, called the ME/MRVQ, which combines the functions of motion estimation (ME) and mean/residual vector quantization (MRVQ) is proposed to improve the coding quality of MPEG in this paper. In the ordinary MPEG design, the ME hardware is idle while coding I-pictures. In general, the process of motion estimation is quite similar to the work of vector quantization coding. They all try to search a best representative from a set of exemplars for every input block. In our design, we perform an extra VQ coding in intraframe compression utilizing the idle hardware for motion estimation. A new intraframe coding scheme, called the cascading MRVQ-DCT, is proposed for incorporating this hardware design. The cascading MRVQ-DCT performs a VQ coding before executing DCT, quantization and VLC coding. It has the advantages of coding the shade vectors by VQ and coding the edge vectors by DCT. Thus, the blocking effects in DCT coder under low bit rate is cured. The coding efficiency of the cascading MRVQ-DCT scheme is investigated by software simulations. It is shown that the rate-distortion performance is uniformly improved.

Huang, Shih-Yu; Hsieh, Kuen-Rong; Wang, Jia-Shung

1994-09-01

66

A fully parallel vector-quantization processor for real-time motion-picture compression  

Microsoft Academic Search

A vector-quantization (VQ) processor system has been developed aiming at real-time compression of motion pictures using a 0.6-?m triple-metal CMOS technology. The chip employs a fully parallel single-instruction, multiple-data architecture having a two-stage pipeline. Each pipeline segment consists of 19 cycles, thus enabling the execution of a single VQ operation in only 19 clock cycles. As a result, it has

Akira Nakada; Tadashi Shibata; Masahiro Konda; Tatsuo Morimoto; Tadahiro Ohmi

1999-01-01

67

Optimization of transform coefficient selection and motion vector estimation considering interpicture dependencies in hybrid video coding  

NASA Astrophysics Data System (ADS)

Considering inter-picture dependencies when selecting transform coefficient levels in hybrid video coding can be done via formulating the decoding process as a linear signal model and solving a quadratic program. The basic method assumes motion estimation and quantization parameters as being given and then selects the transform coefficient levels. However, when motion vectors are determined in advance, motion estimation must be conducted using uncoded reference pictures which is known to deliver inferior results compared to motion estimation on decoded reference pictures. In this work, we expand the basic method to incorporate the case where the motion estimation is considering decoded reference pictures. We propose an approach that iterates between transform coefficient selection and motion estimation. We find that a simple two-pass iteration works reasonably well. Our simulation results using an H.264/AVC-conforming encoder show coding gains up to 1 dB in comparison to the quantization method specified in the test model of H.264/AVC.

Schumitsch, Brad; Schwarz, Heiko; Wiegand, Thomas

2005-03-01

68

Continued Proper Motions of the Magellanic Clouds: Orbits, Internal Kinematics, and Distance  

NASA Astrophysics Data System (ADS)

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in the Magellanic Clouds centered on background quasars. We used these data to determine the proper motions of the LMC and SMC to better than 5% and 15% respectively. The results had a number of unexpected implications for the Milky Way-LMC-SMC system and received considerable attention in the literature and in the press. The implied three-dimensional velocities are larger than previously believed and close to the escape velocity in a standard 10^12 solar mass Milky Way dark halo. Our orbit calculations suggest the Clouds may not be bound to the Milky Way or may just be on their first passage, both of which are unexpected in view of traditional interpretations of the Magellanic Stream. Alternatively, the Milky Way dark halo may be a factor two more massive than previously believed, which would be surprising in view of other observational constraints. Also, the relative velocity between the LMC and SMC was larger than expected, leaving open the possibility that the Clouds may not be bound to each other. To further verify and refine our results we requested an additional epoch data in Cycle 16 which is being executed with WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC field shows that the field proper motion using all three epochs of data is consistent within 1-sigma with the two-epoch data, thus verifying that there are no major systematic effects in our previous measurements. The random errors, however, are only smaller by a factor of 1.4 because of the relatively large errors in the WFPC2 data. A prediction for a fourth epoch with measurement errors similar to epochs 1 and 2 shows that the uncertainties will improve by a factor of 3. This will allow us to better address whether the Clouds are indeed bound to each other and to the Milky Way. It will also allow us to constrain the internal motions of various populations within the Clouds, and to determine a distance to the LMC using rotational parallax. Continuation of this highly successful program is therefore likely to provide important additional insights. Execution in SNAPshot mode guarantees maximally efficient use of HST resources.;

Kallivayalil, Nitya

2008-07-01

69

Systemic and Internal motions of the Magellanic Clouds: Third Epoch Images  

NASA Astrophysics Data System (ADS)

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in the Magellanic Clouds centered on background quasars. We used these data to determine the proper motions of the LMC and SMC to better than 5% and 15% respectively. These are by far the best determinations of the proper motions of these two galaxies. The results have a number of unexpected implications for the Milky Way-LMC-SMC system. The implied three-dimensional velocities are larger than previously believed, and are not much less than the escape velocity in a standard 10^12 solar mass Milky Way dark halo. Orbit calculations suggest the Clouds may not be bound to the Milky Way or may just be on their first passage, both of which would be unexpected in view of traditional interpretations of the Magellanic Stream. Alternatively, the Milky Way dark halo may be a factor of two more massive than previously believed, which would be surprising in view of other observational constraints. Also, the relative velocity between the LMC and SMC is larger than expected, leaving open the possibility that the Clouds may not be bound to each other. To further verify and refine our results we now request an epoch of WFPC2/PC data for the fields centered on 40 quasars that have at least one epoch of ACS imaging. We request execution in snapshot mode, as in our previous programs, to ensure the most efficient use of HST resources. A third epoch of data of these fields will provide crucial information to verify that there are no residual systematic effects in our previous measurements. More importantly, it will increase the time baseline from 2 to 5 yrs and will increase the number of fields with at least two epochs of data. This will reduce our uncertainties correspondingly, so that we can better address whether the Clouds are indeed bound to each other and to the Milky Way. It will also allow us to constrain the internal motions of various populations within the Clouds, and will allow us to determine a distance to the LMC using rotational parallax.;

Kallivayalil, Nitya

2007-07-01

70

A Motion-Stabilized W-Band Radar for Shipboard Observations of Marine Boundary-Layer Clouds  

NASA Astrophysics Data System (ADS)

Cloud radars at X, Ka and W-bands have been used in the past for ocean studies of clouds, but the lack of suitable stabilization has limited their usefulness in obtaining accurate measurements of the velocity structure of cloud particles and the heights of cloud features. A 94 GHz (W-band) radar suitable for use on shipboard studies of clouds has been developed that is small and lightweight and can maintain the radar's beam pointing in the vertical to reduce the affects of the pitch and roll of the ship. A vertical velocity sensor on the platform allows the effects of the ship's heave to be removed from the measured cloud particle motions. Results from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex) field program on the NOAA vessel Ronald H. Brown demonstrate the improvements to the cloud measurements after the ship's motion effects are removed. The compact design of the radar also makes it suitable for use in aircraft studies. The radar is being repackaged to fit in an aft bay of a NOAA P3 aircraft to observe sea-spray profiles during ocean storms.

Moran, Ken; Pezoa, Sergio; Fairall, Chris; Williams, Chris; Ayers, Tom; Brewer, Alan; de Szoeke, Simon P.; Ghate, Virendra

2012-04-01

71

ON THE INTERPRETATION OF RECENT PROPER MOTION DATA FOR THE LARGE MAGELLANIC CLOUD  

SciTech Connect

Recent observational studies using the Hubble Space Telescope have derived the center-of-mass proper motion (CMPM) of the Large Magellanic Cloud (LMC). Although these studies carefully treated both rotation and perspective effects in deriving the proper motion (PM) for each of the sampled fields, they did not consider the effects of local random motion in the derivation. This means that the average PM of the fields (i.e., the observed CMPM) could significantly deviate from the true CMPM, because the effect of local random motion cannot be close to zero in making the average PM for the small number of fields ({approx}10). We discuss how significantly the observationally derived CMPM can deviate from the true CMPM by applying the same method as used in the observations for a dynamical model of the LMC with a known true CMPM. We find that the deviation can be as large as {approx}50 km s{sup -1} ({approx}0.21 mas yr{sup -1}), if the LMC has a thick disk and a maximum circular velocity of {approx}120 km s{sup -1}. We also find that the deviation depends both on the total number of sampled fields and on the structure and kinematics of the LMC. We therefore suggest that there is a possibility that the observed CMPM of the LMC deviates from the true one to some extent. We also show that a simple mean of PM for a large number of LMC fields ({approx}1000) can be much closer to the true CMPM.

Bekki, Kenji [ICRAR, M468, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

2011-03-20

72

GPS determined eastward Sundaland motion with respect to Eurasia confirmed by earthquakes slip vectors at Sunda and Philippine trenches  

NASA Astrophysics Data System (ADS)

GPS measurements acquired over Southeast Asia in 1994 and 1996 in the framework of the GEODYSSEA program revealed that a large piece of continental lithosphere comprising the Indochina Peninsula, Sunda shelf and part of Indonesia behaves as a rigid `Sundaland' platelet. A direct adjustment of velocity vectors obtained in a Eurasian frame of reference shows that Sundaland block is rotating clockwise with respect to Eurasia around a pole of rotation located south of Australia. We present here an additional check of Sundaland motion that uses earthquakes slip vectors at Sunda and Philippine trenches. Seven sites of the GEODYSSEA network are close to the trenches and not separated from them by large active faults (two at Sumatra Trench, three at Java Trench and two at the Philippine Trench). The difference between the vector at the station and the adjacent subducting plate vector defines the relative subduction motion and should thus be aligned with the subduction earthquake slip vectors. We first derive a frame-free solution that minimizes the upper plate (or Sundaland) motion. When corrected for Australia-Eurasia and Philippines-Eurasia NUVEL1-A motion, the misfit between GPS and slip vectors azimuths is significant at 95% confidence, indicating that the upper plate does not belong to Eurasia. We then examine the range of solutions compatible with the slip vectors azimuths and conclude that the minimum velocity of Sundaland is a uniform 7-10 mm/a eastward velocity. However, introducing the additional constraint of the fit of the GEODYSSEA sites with the Australian IGS reference ones, or tie with the NTUS Singapore station, leads to a much narrower range of solutions. We conclude that Sundaland has an eastward velocity of about 10 mm/a on its southern boundary increasing to 16-18 mm/a on its northern boundary.

Chamot-Rooke, N.; Le Pichon, X.

1999-12-01

73

Time-varying behavior of motion vectors in vection-induced images in relation to autonomic regulation  

Microsoft Academic Search

Virtual reality (VR) is a promising technology in biomedical engineering, but at the same time enlarges another problem called cybersickness. Aiming at suppression of cybersicknes, we are investigating the influences of vection-induced images on the autonomic regulation quantitatively. We used the motion vectors to quantify image scenes and measured electrocardiogram, blood pressure, and respiration for evaluating the autonomic regulation. Using

Tohru Kiryu; Hiroshi Yamada; Masahiro Jimbo; Takehiko Bando

2004-01-01

74

FAST MOTIONS OF GALAXIES IN THE COMA I CLOUD: A CASE OF DARK ATTRACTOR?  

SciTech Connect

We note that nearby galaxies having high negative peculiar velocities are distributed over the sky very inhomogeneously. A part of this anisotropy is caused by the 'Local Velocity Anomaly', i.e., by the bulk motion of nearby galaxies away from the Local Void. However, half of the fast-flying objects reside within a small region known as the Coma I cloud. According to Makarov and Karachentsev, this complex contains 8 groups, 5 triplets, 10 pairs, and 83 single galaxies with a total mass of 4.7 Multiplication-Sign 10{sup 13} M{sub Sun }. We use 122 galaxies in the Coma I region with known distances and radial velocities V{sub LG} < 3000 km s{sup -1} to draw the Hubble relation for them. The Hubble diagram shows a Z-shaped effect of infall with an amplitude of +200 km s{sup -1} on the nearby side and -700 km s{sup -1} on the back side. This phenomenon can be understood as the galaxy infall toward a dark attractor with a mass of {approx}2 Multiplication-Sign 10{sup 14} M{sub Sun} situated at a distance of 15 Mpc from us. The existence of a large void between the Coma and Virgo clusters also probably affects the Hubble flow around the Coma I.

Karachentsev, Igor D.; Nasonova, Olga G. [Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhniy Arkhyz, Karachei-Cherkessia 369167 (Russian Federation); Courtois, Helene M., E-mail: ikar@luna.sao.ru, E-mail: h.courtois@ipnl.in2p3.fr, E-mail: phiruzi@gmail.com [Universite de Lyon, Universite Lyon 1, CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne (France)

2011-12-20

75

Fast Motions of Galaxies in the Coma I Cloud: A Case of Dark Attractor?  

NASA Astrophysics Data System (ADS)

We note that nearby galaxies having high negative peculiar velocities are distributed over the sky very inhomogeneously. A part of this anisotropy is caused by the "Local Velocity Anomaly," i.e., by the bulk motion of nearby galaxies away from the Local Void. However, half of the fast-flying objects reside within a small region [R.A.= 11{.\\!\\!^{ h}}5{--}13{.\\!\\!^{ h}}0, decl.= +20^{\\circ } {--}40^{\\circ }] known as the Coma I cloud. According to Makarov & Karachentsev, this complex contains 8 groups, 5 triplets, 10 pairs, and 83 single galaxies with a total mass of 4.7 × 1013 M ?. We use 122 galaxies in the Coma I region with known distances and radial velocities V LG < 3000 km s-1 to draw the Hubble relation for them. The Hubble diagram shows a Z-shaped effect of infall with an amplitude of +200 km s-1 on the nearby side and -700 km s-1 on the back side. This phenomenon can be understood as the galaxy infall toward a dark attractor with a mass of ~2 × 1014 M ? situated at a distance of 15 Mpc from us. The existence of a large void between the Coma and Virgo clusters also probably affects the Hubble flow around the Coma I.

Karachentsev, Igor D.; Nasonova, Olga G.; Courtois, Helene M.

2011-12-01

76

Characterization of Jupiter's Vertical Cloud Structure and Atmospheric Motions: CYCLE4 High  

NASA Astrophysics Data System (ADS)

The primary scientific objective of this proposal is to continue the investigation to determine the state and long-term evolution of the dynamical and cloud regimes in Jupiter's atmosphere, with special emphasis on the region between +/- 15 degrees planetocentric latitude. This objective is an essential part of a larger research effort which includes the acquisition and analysis of data from the Galileo orbiter and probe, and the analysis of ground-based and Voyager data. The goal of this effort is to understand the general meteorology of Jupiter's visible atmosphere and the nature of the transport processes that occur within it. Filters and observing sequences have been chosen to allow us to evaluate the extent to which the WFPC2 can be utilized to characterize the spatial and temporal variations in horizontal motions and to discriminate vertical structure. An observing sequence consisting of multicolor observations for two rotations of the planet is requested in March-May 1995 for the post-come t impact era. Due to the red-blindness of the Voyager and the limited data rate from Galileo, HST/WFPC2 is the prime instrument to characterize the state of the Jovian atmosphere before and during the Galileo probe entry epoch. The observat ions in this proposal will help to define whether the probe data are typical of the latitude of entry (6.57 +/-0.5 deg.planetocentric latitude) and the extent t o which they can be extrapolated to other latitudes.

Beebe, Reta

1994-07-01

77

Multiangle Remote Sensing of Optically Thin Cirrus Clouds From MISR Using Support Vector Machines  

Microsoft Academic Search

Thin cirrus clouds, those with optical depths less than 1, can potentially have large radiative effects on the atmospheric and surface energy budgets in regions where they are prevalent. They also present an impediment to the retrieval of clear sky properties such as aerosol optical depth, temperature profiles, etc. Such clouds, however, are notoriously difficult to detect using standard satellite

M. J. Garay; D. Mazzoni; R. Davies; K. Wagstaff

2004-01-01

78

vectors  

NSDL National Science Digital Library

The word vector comes from the Latin term vehere, to carry. In Biology, a vector is an agent which carries disease, such as a mosquito carrying infected blood from one patient to the next. In physics, a vector is a quantity which has both a magnitude and a direction associated with it. The most commonly used example of vectors in everyday life is velocity. When you drive your car, your speedometer tells you the speed of your car, but it doesn't tell you where you are going. The combination of both where you are going and how fast you are going there is your car's velocity.

Joiner, David; The Shodor Education Foundation, Inc.

79

2-D high-frame-rate dynamic elastography using delay compensated and angularly compounded motion vectors: Preliminary results  

Microsoft Academic Search

This paper describes a new ultrasound-based system for high-frame-rate measurement of periodic motion in 2-D for tissue elasticity imaging. Similarly to conventional 2-D flow vector imaging, the system acquires the RF signals from the region of interest at multiple steering angles. A custom sector subdivision technique is used to increase the temporal resolution while keeping the total acquisition time within

R. Z. Azar; A. Baghani; S. E. Salcudean; R. Rohling

2010-01-01

80

Vectors  

NSDL National Science Digital Library

This web page introduces vectors as an extension of numbers having both magnitude and direction. The initial motivation is to describe velocity but the material includes a general discussion of vector algebra and an application to forces for the inclined plane. The page contains links to a related lesson plan and further opportunities to explore vectors. This is part of the extensive web site "From Stargazers to Starships", that uses space exploration and space science to introduce topics in physics and astronomy. Translations in Spanish and French are available.

Stern, David

2006-07-16

81

Automated cloud tracking system for the Akatsuki Venus Climate Orbiter data  

NASA Astrophysics Data System (ADS)

Japanese Venus Climate Orbiter, Akatsuki, is cruising to approach to Venus again although its first Venus orbital insertion (VOI) has been failed. At present, we focus on the next opportunity of VOI and the following scientific observations.We have constructed an automated cloud tracking system for processing data obtained by Akatsuki in the present study. In this system, correction of the pointing of the satellite is essentially important for improving accuracy of the cloud motion vectors derived using the cloud tracking. Attitude errors of the satellite are reduced by fitting an ellipse to limb of an imaged Venus disk. Next, longitude-latitude distributions of brightness (cloud patterns) are calculated to make it easy to derive the cloud motion vectors. The grid points are distributed at regular intervals in the longitude-latitude coordinate. After applying the solar zenith correction and a highpass filter to the derived longitude-latitude distributions of brightness, the cloud features are tracked using pairs of images. As a result, we obtain cloud motion vectors on longitude-latitude grid points equally spaced. These entire processes are pipelined and automated, and are applied to all data obtained by combinations of cameras and filters onboard Akatsuki. It is shown by several tests that the cloud motion vectors are determined with a sufficient accuracy. We expect that longitude-latitude data sets created by the automated cloud tracking system will contribute to the Venus meteorology.

Ogohara, Kazunori; Kouyama, Toru; Yamamoto, Hiroki; Sato, Naoki; Takagi, Masahiro; Imamura, Takeshi

2012-02-01

82

Streaming motions of molecular clouds, ionized hydrogen, and OB stars in the Cygnus arm  

Microsoft Academic Search

The radial velocity fields of molecular clouds, OB stars, and ionized hydrogen in the Cygnus arm (l ? 72–8) are analyzed. A gradient?V\\u000a LSR\\/?lin the mean line-of-sight velocities of molecular clouds and ionized hydrogen due to differential Galactic rotation is detected,\\u000a and two groups of physically and genetically associated objects moving with different line-of-sight velocities are identified.\\u000a One of the

T. G. Sitnik; A. M. Mel’nik; V. V. Pravdikova

2001-01-01

83

Dissociation between hand motion and population vectors from neural activity in motor cortex  

Microsoft Academic Search

The population vector hypothesis was introduced almost twenty years ago to illustrate that a population vector constructed from neural activity in primary motor cortex (MI) of non-human primates could predict the direction of hand movement during reaching. Alternative explanations for this population signal have been suggested but could not be tested experimentally owing to movement complexity in the standard reaching

Stephen H. Scott; Paul L. Gribble; Kirsten M. Graham; D. William Cabel

2001-01-01

84

Fast and Stable Vector Spline Method for Fluid Apparent Motion Estimation  

Microsoft Academic Search

Apparent motion estimated on satellite data is used for ex- ample to compute the wind field in meteorology, and surface currents in oceanography. The satellite images display tur- bulent fluids with strong rotational patterns at different spa- tial and temporal scales. This specificity necessitates devis- ing adapted methods, allowing to control the divergence and curl of the retrieved motion field.

Till Isambert; Jean-paul Berroir; Isabelle Herlin

2007-01-01

85

Large-scale Environmental Variables and Transition to Deep Convection in Cloud Resolving Model Simulations: A Vector Representation  

SciTech Connect

Cloud resolving model simulations and vector analysis are used to develop a quantitative method of assessing regional variations in the relationships between various large-scale environmental variables and the transition to deep convection. Results of the CRM simulations from three tropical regions are used to cluster environmental conditions under which transition to deep convection does and does not take place. Projections of the large-scale environmental variables on the difference between these two clusters are used to quantify the roles of these variables in the transition to deep convection. While the transition to deep convection is most sensitive to moisture and vertical velocity perturbations, the details of the profiles of the anomalies vary from region to region. In comparison, the transition to deep convection is found to be much less sensitive to temperature anomalies over all three regions. The vector formulation presented in this study represents a simple general framework for quantifying various aspects of how the transition to deep convection is sensitive to environmental conditions.

Hagos, Samson M.; Leung, Lai-Yung R.

2012-11-01

86

Large-scale environmental variables and transition to deep convection in cloud resolving model simulations: A vector representation  

NASA Astrophysics Data System (ADS)

Cloud resolving model simulations and vector analysis are used to develop a quantitative method of assessing regional variations in the relationships between various large-scale environmental variables and the transition to deep convection. Results of the CRM simulations from three tropical regions are used to cluster environmental conditions under which transition to deep convection does and does not take place. Projections of the large-scale environmental variables on the difference between these two clusters are used to quantify the roles of these variables in the transition to deep convection. While the transition to deep convection is most sensitive to moisture and vertical velocity perturbations, the details of the profiles of the anomalies vary from region to region. In comparison, the transition to deep convection is found to be much less sensitive to temperature anomalies over all three regions. The vector formulation presented in this study represents a simple general framework for quantifying various aspects of how the transition to deep convection is sensitive to environmental conditions.

Hagos, Samson; Leung, L. Ruby

2012-04-01

87

A vectorized Monte Carlo code to simulate charged-particle motion within crystals  

Microsoft Academic Search

A new Monte Carlo method for the calculation of blocking patterns in single crystals is described. Vectorized execution and use of the same trajectories to simulate many different processes substantially reduce computing time.

F. Malaguti

1988-01-01

88

Recovering shapes of specular objects in motion via normal vector map consistency  

NASA Astrophysics Data System (ADS)

We present a novel method to reconstruct the shape of a moving specular object from multiple camera images taken near a calibrated display with a known color-encoded pattern. The method is based on voxel carving exploiting the consistency of the cones of allowed normal vectors, or normal vector maps (NVMs). The algorithm is highly parallel, does not rely on pattern recognition and applies to surfaces of arbitrary complexity.

Pak, Alexey

2012-09-01

89

Dynamic elastography using delay compensated and angularly compounded high frame rate 2D motion vectors  

Microsoft Academic Search

This paper describes a new ultrasound-based system for high frame rate measurement of periodic motion in 2D for tissue elasticity imaging. The system acquires the RF signals from the region of interest from multiple steering angles in order to reconstruct the 2D motion from 1D estimation along each angle. To increase the temporal resolution, the acquisition area is divided into

Reza Zahiri Azar; Ali Baghani; Septimiu E. Salcudean; Robert Rohling

2010-01-01

90

Jupiter cloud composition, stratification, convection, and wave motion: a view from new horizons.  

PubMed

Several observations of Jupiter's atmosphere made by instruments on the New Horizons spacecraft have implications for the stability and dynamics of Jupiter's weather layer. Mesoscale waves, first seen by Voyager, have been observed at a spatial resolution of 11 to 45 kilometers. These waves have a 300-kilometer wavelength and phase velocities greater than the local zonal flow by 100 meters per second, much higher than predicted by models. Additionally, infrared spectral measurements over five successive Jupiter rotations at spatial resolutions of 200 to 140 kilometers have shown the development of transient ammonia ice clouds (lifetimes of 40 hours or less) in regions of strong atmospheric upwelling. Both of these phenomena serve as probes of atmospheric dynamics below the visible cloud tops. PMID:17932284

Reuter, D C; Simon-Miller, A A; Lunsford, A; Baines, K H; Cheng, A F; Jennings, D E; Olkin, C B; Spencer, J R; Stern, S A; Weaver, H A; Young, L A

2007-10-12

91

ULTRAVIOLET INDUCED MOTION OF A FLUORESCENT DUST CLOUD IN AN ARGON DIRECT CURRENT GLOW DISCHARGE PLASMA  

SciTech Connect

Dusty plasmas consist of electrons, ions, neutrals and nm-?m sized particles commonly referred to as dust. In man-made plasmas this dust may represent impurities in a tokamak or plasma etching processing. In astrophysical plasmas this dust forms structures such as planetary rings and comet tails. To study dusty plasma dynamics an experiment was designed in which a 3:1 silica (<5 ?m diameter) and fl uorescent dust mixture was added to an argon DC glow discharge plasma and exposed to UV radiation. This fl uorescent lighting technique offers an advantage over laser scattering (which only allows two-dimensional slices of the cloud to be observed) and is simpler than scanning mirror techniques or particle image velocimetry. Under typical parameters (P=150 mTorr, V anode= 100 V, Vcathode= -400 V, Itotal < 2mA) when the cloud is exposed to the UV light (100W, ? = 365 nm) the mixture fl uoresces, moves ~2mm towards the light source and begins rotating in a clockwise manner (as seen from the cathode). By calibrating a UV lamp and adjusting the relative intensity of the UV with a variable transformer it was found that both translational and rotational velocities are a function of UV intensity. Additionally, it was determined that bulk cloud rotation is not seen when the dust tray is not grounded while bulk translation is. This ongoing experiment represents a novel way to control contamination in man-made plasmas and a path to a better understanding of UV-bathed plasma systems in space..

Hvasta, M.G.; and Zwicker, A.

2008-01-01

92

Motion.  

ERIC Educational Resources Information Center

This monograph was written for the Conference on the New Instructional Materials in Physics held at the University of Washington in summer, 1965. It is intended for use in an introductory course in college physics. It consists of an extensive qualitative discussion of motion followed by a detailed development of the quantitative methods needed to…

Gerhart, James B.; Nussbaum, Rudi H.

93

Motion.  

ERIC Educational Resources Information Center

|This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

Brand, Judith, Ed.

2002-01-01

94

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)  

SciTech Connect

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Christopher Williams; Mike Jensen

2012-11-06

95

34/45-Mbps 3D HDTV digital coding scheme using modified motion compensation with disparity vectors  

NASA Astrophysics Data System (ADS)

This paper describes a digital compression coding scheme for transmitting three dimensional stereo HDTV signals with full resolution at bit-rates around 30 to 40 Mbps to be adapted for PDH networks of the CCITT 3rd digital hierarchy, 34 Mbps and 45 Mbps, SDH networks of 52 Mbps and ATM networks. In order to achieve a satisfactory quality for stereo HDTV pictures, three advanced key technologies are introduced into the MPEG-2 Multi-View Profile, i.e., a modified motion compensation using disparity vectors estimated between the left and right pictures, an adaptive rate control using a common buffer memory for left and right pictures encoding, and a discriminatory bit allocation which results in the improvement of left pictures quality without any degradation of right pictures. From the results of coding experiment conducted to evaluate the coding picture achieved by this coding scheme, it is confirmed that our coding scheme gives satisfactory picture quality even at 34 Mbps including audio and FEC data.

Naito, Sei; Matsumoto, Shuichi

1998-12-01

96

Investigation of Cb motion in the province of Alberta (Canada)  

Microsoft Academic Search

Cb motion is analyzed in the paper. Strom observations were carried out in the province of Alberta (Canada) in 2005 with the\\u000a help of radar. A new approach, based on determination of the vector of cloud track between radar scans, was used to study\\u000a motion characteristics. Results of observations have shown that storms moved straight with some offset to the

T. W. Krauss; A. A. Sinkevich

2007-01-01

97

Noise Robust Motion Refinement for Motion Compensated Noise Reduction  

NASA Astrophysics Data System (ADS)

A motion refinement algorithm is proposed to enhance motion compensated noise reduction (MCNR) efficiency. Instead of the vector with minimum distortion, the vector with minimum distance from motion vectors of neighboring blocks is selected as the best motion vector among vectors which have distortion values within the range set by noise level. This motion refinement finds more accurate motion vectors in the noisy sequences. The MCNR with the proposed algorithm maintains the details of an image sequence very well without blurring and joggling. And it achieves 10% bit-usage reduction or 0.5dB objective quality enhancement in subsequent video coding.

Kim, Jong-Sun; Kim, Lee-Sup

98

Descent motions of the Huygens probe as measured by the Surface Science Package (SSP): Turbulent evidence for a cloud layer  

Microsoft Academic Search

The Huygens probe underwent vigorous short-period motions during its parachute descent through the atmosphere of Saturn's moon Titan in January 2005, at least some of which were excited by the Titan environment. Several sensors in the Huygens Surface Science Package (SSP) detect these motions, indicating the transition to the smaller stabilizer parachute, the changing probe spin rate, aerodynamic buffeting, and

Ralph D. Lorenz; John C. Zarnecki; Martin C. Towner; Mark R. Leese; Andrew J. Ball; Brijen Hathi; Axel Hagermann; Nadeem A. L. Ghafoor

2007-01-01

99

Pyramidal motion estimation techniques exploiting intra-level motion correlation  

Microsoft Academic Search

The conventional pyramidal motion estimation technique, although capable of reducing the heavy computational load as required by the full search block matching algorithm, has the problem of propagating false motion vectors. In this work, pyramidal motion estimation techniques that exploit the intra-level motion correlation to overcome this serious drawback are presented. Instead of scaling the motion vectors from the corresponding

Jinwen Zan; M. Omair Ahmad; M. N. S. Swamy

2003-01-01

100

Saturn's Zonal Winds at Cloud Level  

NASA Astrophysics Data System (ADS)

We present an analysis of new cloud motion measurements in Saturn's atmosphere from Voyager 1 and 2 images and define a nominal zonal wind velocity vs latitude profile for the cloud top level that can be used as reference for the upcoming Cassini mission. Improvements over previous studies include: (i) twice the number of wind vectors used, (ii) independent measurements of cloud tracers, (iii) extended latitudinal coverage, (iv) strict error control and evaluation, and (v) a new zonal averaging methodology. Mean zonal wind velocities are given for the latitude range 81° to -71° (planetographic) in steps of 0.5° with a gap between 0° and -10° due to ring shadowing. This research also includes the study of the morphology and motions of cloud systems in the equator and in the southern hemisphere which have not been described previously. We give an ephemeris (motion equation) for several long-lived features that could be observable if they survive until Cassini arrives on Saturn. The long-term behavior of the zonal wind profile is studied by comparing it with a complete set of wind velocities compiled from historical and modern ground-based and HST observations. Significant changes are noted in the equatorial jet between this set and the nominal Voyager profile. We discuss in detail the possible origin for such differences.

Sanchez-Lavega, Agust?´n.; Rojas, José F.; Sada, Pedro V.

2000-10-01

101

Automatic generation of time resolved motion vector fields of coronary arteries and 4D surface extraction using rotational x-ray angiography  

NASA Astrophysics Data System (ADS)

Rotational coronary angiography provides a multitude of x-ray projections of the contrast agent enhanced coronary arteries along a given trajectory with parallel ECG recording. These data can be used to derive motion information of the coronary arteries including vessel displacement and pulsation. In this paper, a fully automated algorithm to generate 4D motion vector fields for coronary arteries from multi-phase 3D centerline data is presented. The algorithm computes similarity measures of centerline segments at different cardiac phases and defines corresponding centerline segments as those with highest similarity. In order to achieve an excellent matching accuracy, an increasing number of bifurcations is included as reference points in an iterative manner. Based on the motion data, time-dependent vessel surface extraction is performed on the projections without the need of prior reconstruction. The algorithm accuracy is evaluated quantitatively on phantom data. The magnitude of longitudinal errors (parallel to the centerline) reaches approx. 0.50 mm and is thus more than twice as large as the transversal 3D extraction errors of the underlying multi-phase 3D centerline data. It is shown that the algorithm can extract asymmetric stenoses accurately. The feasibility on clinical data is demonstrated on five different cases. The ability of the algorithm to extract time-dependent surface data, e.g. for quantification of pulsating stenosis is demonstrated.

Jandt, Uwe; Schäfer, Dirk; Grass, Michael; Rasche, Volker

2009-01-01

102

Ion storage combined with reflectron time-of-flight mass spectrometry: ion cloud motions as a result of jet-cooled molecules  

NASA Astrophysics Data System (ADS)

The storage of molecular ions in a quadrupole ion trap in combination with reflectron time-of-flight mass spectrometry, jet cooling and multiphoton laser ionization is presented. Jet-cooled molecules are introduced as neutrals into the ion trap and ionized by multiphoton absorption. Varying the storage time causes a dramatic change in the ion intensities, depending on their m/z ratio. This observation cannot be explained by electronic synchronization effects, but is identified as secular motions of the stored ions. In this paper it is demonstrated that for a time span of up to several milliseconds the ions remain coherent in space and kinetic energy. The molecular ions as well as their fragment ions are not dispersed in the ion trap but move in close ion clouds describing Lissajous trajectories. Consequently, the distance between the middle of the ion trap and the ion cloud periodically changes, resulting in a storage time dependence on mass resolution, flight time and signal intensity. The influences of storage time and other trapping parameters as well as their effect on the interpretation of the results, which are obtained in investigations of time-resolved ion processes, will be discussed.

Wilhelm, U.; Aicher, K. P.; Grotemeyer, J.

1996-02-01

103

Center manifolds, normal forms and bifurcations of vector fields with application to coupling between periodic and steady motions  

NASA Astrophysics Data System (ADS)

We study the instabilities known to aeronautical engineers as flutter and divergence. Mathematically, these states correspond to bifurcations to limit cycles and multiple equilibrium points in a differential equation. Making use of the center manifold and normal form theorems, we concentrate on the situation in which flutter and divergence become coupled, and show that there are essentially two ways in which this is likely to occur. In the first case the system can be reduced to an essential model which takes the form of a single degree of freedom nonlinear oscillator. This system, which may be analyzed by conventional phase-plane techniques, captures all the qualitative features of the full system. We discuss the reduction and show how the nonlinear terms may be simplified and put into normal form. Invariant manifold theory and the normal form theorem play a major role in this work and this paper serves as an introduction to their application in mechanics. Repeating the approach in the second case, we show that the essential model is now three dimensional and that far more complex behavior is possible, including nonperiodic and `chaotic' motions. Throughout, we take a two degree of freedom system as an example, but the general methods are applicable to multi- and even infinite degree of freedom problems.

Holmes, Philip J.

1981-06-01

104

Horizontal structure of planetary-scale waves at the cloud top of Venus deduced from Galileo SSI images with an improved cloud-tracking technique  

NASA Astrophysics Data System (ADS)

An improved cloud tracking method for deriving wind velocities from successive planetary images was developed. The new method incorporates into the traditional cross-correlation method an algorithm that corrects for erroneous cloud motion vectors by re-determining the most plausible correlation peak among all of the local maxima on the correlation surface by comparing each vector with its neighboring vectors. The newly developed method was applied to the Venusian violet images obtained by the Solid State Imaging system (SSI) onboard the Galileo spacecraft during its Venus flyby. Although the results may be biased by the choice of spatial scale of atmospheric features, the cloud tracking is the most practical mean of estimating the wind velocities with extensive spatial and temporal coverage. The two-dimensional distribution of the horizontal wind vector field over 5 days was obtained. It was found from these wind maps that the solar-fixed component in 1990 was similar to that in 1982 obtained by the Pioneer Venus orbiter. The deviation of the instantaneous zonal wind field from the solar-fixed component shows a distinct wavenumber-1 structure in the equatorial region. On the assumption that this structure is a manifestation of an equatorial Kelvin wave, the phase relationship between the zonal wind and the cloud brightness suggests a short photochemical lifetime of the violet absorber. The momentum deposition by this Kelvin wave, which is subject to radiative damping, would induce a westward mean-wind acceleration of ˜0.3 m s -1 per Earth day.

Kouyama, Toru; Imamura, Takeshi; Nakamura, Masato; Satoh, Takehiko; Futaana, Yoshihumi

2012-01-01

105

A Sharper View of Venus:Strategies For Precise Cloud Tracking of Venus' Lower Cloud Deck  

NASA Astrophysics Data System (ADS)

We have observed the nightside of Venus at 2.3 microns using both IRTF on Mauna Kea and APO in New Mexico during the past two inferior conjuctions. Using IRTF we observed over a ten day span for 3-hours each day, which is sufficient to determine the major cloud motions. More recently by using both APO and IRTF we achieved a 5-hour temporal baseline each day over six days of observation. We see the lower cloud deck of Venus (48-52 km) backlit by 2.3 micron thermal radiation emanating from the surface and the lower atmosphere. These observations have allowed us to derive cloud-level wind speeds, and identify transient features in the observed Venusian wind field. We have adapted feature-tracking algorithms from several terrestrial remote sensing applications (e.g., Wu Inter. J. Remote Sensing, 1997, 2003; Bhat IEEE Trans. on PAMI, 20, 1998; Evans, IEEE Proc. of IGRSS, 1999) in order to track cloud movement. While this is still a work in progress, we show wind vector fields based on these algorithms and discuss their potential advantages and shortfalls. Our observations typically consist of many (a few thousand) short exposures of Venus during each twilight opportunity. These sequences lend themselves to image restoration processing by iterative blind deconvolution. We present restorations implemented using "IDAC" (Jefferies and Christou, ApJ, 415, 1993), a code that is distributed through the Center for Adaptive Optics at UC Santa Cruz. The use of IDAC has significantly increased the resolution of our ground based observations of Venus. This increases the accuracy of our wind speed measurements to the point were we can look for meridional motion. We will be presenting our most recent results and vector fields. This work supported by NASA's Infrared Telescope Facility and by the NASA Planetary Astronomy Program.

Tavenner, Tanya; Young, E. F.; Murphy, J.; Coyote, S.; Bullock, M.; Rafkin, S.

2006-09-01

106

Exploring acceleration through vectors  

NSDL National Science Digital Library

This in class worksheet is designed to get students to think about and manipulate different accelerations in their head. Students work together with written descriptions of velocity and acceleration and draw the vectors in part one, and then turn that around in part two where they write descriptions of a car's motion based on the vector pictures they are given.

107

Cold, Clouds, and Snowflakes  

NSDL National Science Digital Library

Snow and ice are both precipitation, that is, the processes that remove water from clouds. Clouds, regions of the atmosphere with high relative humidity, are made of droplets of water and perhaps bits of ice. Even though water is much denser than air, these droplets and ice crystals are small enough to be suspended by random upward air motion. When these droplets or crystals join together, gravity overcomes the suspending force and we have precipitation. In this lesson, students will investigate NASA satellite data to determine geographical areas where wintry precipitation may have occurred based on cloud top temperature. They will explore the relationship between the amount of water vapor and the temperature of clouds, as well as snowflake shapes and cloud temperature.

108

Motion-Compensated Frame Interpolation Using Bilateral Motion Estimation and Adaptive Overlapped Block Motion Compensation  

Microsoft Academic Search

In this work, we develop a new motion-compe (MC) interpolation algorithm to enhance the temporal resolution of video sequences. First, we propose the bilateral motion estimation scheme to obtain the motion field of an interpolated frame without yielding the hole and overlapping problems. Then, we partition a frame into several object regions by clustering motion vectors. We apply the variable-size

Byeong-Doo Choi; Jong-Woo Han; Chang-Su Kim; Sung-Jea Ko

2007-01-01

109

Qualitative Analysis of Cloud Computing Risks and Framework for the Rationalization and Mitigation of Cloud Risks  

Microsoft Academic Search

Cloud computing is a popular subject across the IT industry, but risks associated with this new technology and delivery model are not yet well understood. This research investigates, in a qualitative fashion, the vectors that contribute to cloud computing risks in the areas of security, business, and compliance. The focus of this research is on the identification of risk vectors

Maria Azua Himmel

2012-01-01

110

Cloud Fun  

NSDL National Science Digital Library

Learners complete a series of hands-on and investigative activities to explore cumulus clouds. Learners observe cumulus clouds outside, read a book about how cumulus clouds differ from other clouds, and create a list of words that describe cumulus clouds. Then, learners create their own cumulus cloud out of white paper and complete the Cloud Fun Student Activity sheet that includes a description of the cloud and what the weather was like on the day the cloud was observed. Learners will use their five senses to describe their clouds. Clouds can be displayed in the classroom or assembled into a class book. This lesson guide includes brief background information about cumulus clouds, adaptations for younger and older learners, and extension ideas.

Program, The G.

2006-01-01

111

Hierarchical variable block size motion estimation technique for motion sequence coding  

NASA Astrophysics Data System (ADS)

Motion-compensated coding, which exploits the temporal redundancies in the moving image, is one of the most popular techniques currently used. Recently, a variable block size (VBS) motion estimation technique has been proposed to improve the performance of the motion- compensated transform coding (MCTC). This technique allows larger blocks to be used when smaller blocks provide little gain, saving the bit rates especially for areas containing more complex motion. However, there have been few efforts to investigate an efficient VBS motion structure for reducing the motion vector coding rates further. Hence, a new VBS motion estimation technique based on a hierarchical structure is proposed that improves the motion vector encoding efficiency and reduces the number of motion vectors to be transmitted as well. Specifically, the gain/cost motion estimation technique with the selective motion prediction is utilized for the topmost level motion vector search, exploiting the redundancies among the neighboring motion vectors. Also, a restricted search with respect to the topmost level motion vector enables more flexible and efficient motion vector encoding for the remaining lower level blocks. Intensive simulations on several moving image sequences show that the MTC employing the VBS motion estimation provides a performance improvement of 0.7 to 1.0 dB, in terms of peak SNR, compared with the fixed block size motion estimation.

Kim, Jong-Won; Lee, Sang U.

1994-08-01

112

The Impact of Aircraft Dropsonde and Satellite Wind Data on Numerical Simulations of Two Landfalling Tropical Storms during the Tropical Cloud Systems and Processes Experiment  

Microsoft Academic Search

Dropwindsonde, Geostationary Operational Environmental Satellite-11 (GOES-11) rapid-scan atmo- spheric motion vectors, and NASA Quick Scatterometer (QuikSCAT) near-surface wind data collected during NASA's Tropical Cloud Systems and Processes (TCSP) field experiment in July 2005 were assimi- lated into an advanced research version of the Weather Research and Forecasting (WRF) model using its three-dimensional variational data assimilation (3DVAR) system. The impacts of

Zhaoxia Pu; Xuanli Li; Christopher S. Velden; Sim D. Aberson; W. Timothy Liu

2008-01-01

113

Cloud Protocols  

NSDL National Science Digital Library

The purpose of this activity is to observe the type and cover of clouds including contrails. Students observe which of ten types of clouds and how many of three types of contrails are visible and how much of the sky is covered by clouds (other than contrails) and how much is covered by contrails. Intended outcomes are that students learn how to make estimates from observations and how to categorize specific clouds following general descriptions for the categories. They will learn the meteorological concepts of cloud heights, types, and cloud cover and learn the ten basic cloud types. Supporting background materials for both student and teacher are included.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

114

An overlapped block motion compensation for high quality motion picture coding  

Microsoft Academic Search

An overlapped block motion compensation scheme, which is especially suitable for hybrid coding schemes combine with overlapped transforms, is described. Motion compensation is achieved using enlarged and overlapped blocks. When motion estimation is executed, a window function operates on the prediction error signals. The power of the resulting signal is calculated and used for motion vector evaluation. When motion-compensated prediction

Satoshi Nogaki; Mutsumi Ohta

1992-01-01

115

Picture-level parameteric motion representation for efficient motion compensation  

Microsoft Academic Search

When a picture contains non-translational motions in it, a picture-level parametric motion model can be more efficient than the block-based translational motion model because the former has small number of parameters that can replace many motion vectors of individual blocks. In addition, the former can represent the deformation of the image better than the latter. Based on this idea, we

Jaewon Sung; Seung-Wook Park; Byeong-Moon Jeon

2011-01-01

116

Cooperative Phenomena in the Perception of Motion Direction,  

National Technical Information Service (NTIS)

A percept of global coherent motion can result from the combination of many different localized motion vectors. We report evidence of hysteresis in the perception of this global motion, obtained with random-dot cinematograms. The hysteresis characteristic...

D. Williams G. Phillips

1987-01-01

117

Project Physics Reader 1, Concepts of Motion.  

ERIC Educational Resources Information Center

As a supplement to Project Physics Unit 1, 21 articles are presented in this reader. Concepts of motion are discussed under headings: motion, motion in words, representation of movement, introducing vectors, Galileo's discussion of projectile motion, Newton's laws of dynamics, the dynamics of a golf club, report on Tait's lecture on force, and bad…

Harvard Univ., Cambridge, MA. Harvard Project Physics.

118

Cloud Watch  

NSDL National Science Digital Library

The purpose of this activity is to explore the connections between cloud type, cloud cover, and weather and stimulate student interest in taking cloud type observations. Students observe cloud type and coverage and weather conditions over a five-day period and correlate these observations. Students make and test predictions using these observations. The intended outcome is that students learn to draw inferences from observations and use them to make and test predictions.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

119

Cloud Types  

NSDL National Science Digital Library

This tutorial explains common cloud classifications and the Latin root words that have been adapted to create the various names of clouds. The classification is subdivided into high-, low-, and mid-level types, clouds with vertical development, and other, less common types. Each description is accompanied by an example photograph.

2005-03-10

120

Vector Addition  

NSDL National Science Digital Library

This 2D applet simulates vector addition geometrically. The user selects the angle and magnitude of two vectors, which are then added together by the applet. The resultant vector and the values of its magnitude and angle, as well as the values of the x and y components of all three vectors, are calculated and displayed.

Duffy, Andrew

2004-11-28

121

Vector Calculator  

NSDL National Science Digital Library

A simple Java applet enabling users to add two two-dimensional vectors. The user can choose the two vectors by clicking on a grid. The components, magnitude, and direction are immediately shown. Once the two vectors are chosen, a press of a button shows the vector sum, its components, its magnitude and its direction.

Gea-Banacloche

2009-08-10

122

Multiscale cloud system modeling  

NASA Astrophysics Data System (ADS)

The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing ˜1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

Tao, Wei-Kuo; Moncrieff, Mitchell W.

2009-12-01

123

Radiation effect of invisible clouds  

NASA Astrophysics Data System (ADS)

Super thin clouds such as cirrus and other invisible clouds are found in ~50% of global observations. Passive remote sensing techniques such as the MODIS (King et al., 1992) generally fail to detect optically thin clouds. The launch of NASA's CALIPSO (Winker et al. 2003) provides an unprecedented ability to detect thin cloud layers globally. Also, the CERES (Wielicki et al 1996) provides accurate measurements of the TOA radiation flux. By using CERES, MODIS and CALIPSO measurements in a synergistic manner, a quantitative assessment of the influence of invisibly thin clouds on the Earth's radiation is accomplished. The difference between clear-sky radiation flux and invisibly-cloudy-sky flux clearly shows the cooling effect of invisible clouds in shortwave (SW). The invisible clouds increase the diurnal mean outgoing SW flux by ~2.5W Wm-2. Our results also show that the extent of the Hadley cell could reliably be estimated by measuring the height of the uppermost invisible clouds in the troposphere with space-borne lidar. Through consecutive multi-year measurements of the height of the uppermost super-thin clouds, a good estimation of the expansion of the Hadley cell could be obtained. Moreover, our full-vector radiative transfer modeling results show that the super-thin clouds can largely reduce the polarization of the radiation from the earth surface, and if not treated accurately the invisible clouds could cause significant bias errors in the polarization dependence models (PDM) for the inter-calibration project of the CLARREO mission and significant bias errors in the aerosol product NASA's Glory mission will produce. Intensive measurements and studies should be performed for these globally distributed super-thin clouds.

Sun, W.; Nasa Clarreo; Glory

2011-12-01

124

A Porn Video Detecting Method Based on Motion Features Using HMM  

Microsoft Academic Search

This paper proposes a method of identified reciprocating motion in pornographic video from other human action using Hidden Markov Model (HMM). The motion vectors are obtained by decoding the compressed MPEG video. Then the feature vectors are extracted by calculating the direction and the magnitude of the motion vectors. The feature vectors are fed to Hidden Markov Model for training

Zhiyi Qu; Yanmin Liu; Ying Liu; Kang Jiu; Yong Chen

2009-01-01

125

A dust cloud around Pluto and Charon  

Microsoft Academic Search

We suggest that Pluto and Charon are immersed in a tenuous dust cloud. The cloud consists of ejecta from Pluto and—especially—Charon, released from their surfaces by impacts of micrometeoroids originating from Edgeworth–Kuiper belt objects. The motion of the ejected grains is dominated by the gravity of Pluto and Charon, which determines a pear-shape of the densest part of the cloud.

K.-U. Thiessenhusen; A. V. Krivov; H. Krüger; E. Grün

2002-01-01

126

EDITORIAL: Focus on Cloud Physics FOCUS ON CLOUD PHYSICS  

NASA Astrophysics Data System (ADS)

Cloud physics has for a long time been an important segment of atmospheric science. It is common knowledge that clouds are crucial for our understanding of weather and climate. Clouds are also interesting by themselves (not to mention that they are beautiful). Complexity is hidden behind the common picture of these beautiful and interesting objects. The typical school textbook definition that a cloud is 'a set of droplets or particles suspended in the atmosphere' is not adequate. Clouds are complicated phenomena in which dynamics, turbulence, microphysics, thermodynamics and radiative transfer interact on a wide range of scales, from sub-micron to kilometres. Some of these interactions are subtle and others are more straightforward. Large and small-scale motions lead to activation of cloud condensation nuclei, condensational growth and collisions; small changes in composition and concentration of atmospheric aerosol lead to significant differences in radiative properties of the clouds and influence rainfall formation. It is justified to look at a cloud as a composite, nonlinear system which involves many interactions and feedback. This system is actively linked into a web of atmospheric, oceanic and even cosmic interactions. Due to the complexity of the cloud system, present-day descriptions of clouds suffer from simplifications, inadequate parameterizations, and omissions. Sometimes the most fundamental physics hidden behind these simplifications and parameterizations is not known, and a wide scope of view can sometimes prevent a 'microscopic', deep insight into the detail. Only the expertise offered by scientists focused on particular elementary processes involved in this complicated pattern of interactions allows us to shape elements of the puzzle from which a general picture of clouds can be created. To be useful, every element of the puzzle must be shaped precisely. This often creates problems in communication between the sciences responsible for shaping elements of the puzzle, and those which combine them. Scales, assumptions and the conditions used in order to describe a particular single process of interest must be consistent with the conditions in clouds. The papers in this focus issue of New Journal of Physics collectively demonstrate (i) the variation in scientific approaches towards investigating cloud processes, (ii) the various stages of shaping elements of the puzzle, and (iii) some attempts to put the pieces together. These papers present just a small subset of loosely arranged elements in an initial stage of puzzle creation. Addressed by this issue is one of the important problems in our understanding of cloud processes—the interaction between cloud particles and turbulence. There is currently a gap between the cloud physics community and scientists working in wind tunnels, on turbulence theory and particle interactions. This collection is intended to narrow this gap by bringing together work by theoreticians, modelers, laboratory experimentalists and those who measure and observe actual processes in clouds. It forms a collage of contributions showing various approaches to cloud processes including: • theoretical works with possible applications to clouds (Bistagnino and Boffetta, Gustavsson et al), • an attempt to construct a phenomenological description of clouds and rain (Lovejoy and Schertzer), • simplified models designed to parameterize turbulence micro- and macro-effects (Celani et al, Derevyanko et al), • focused theoretical research aimed at particular cloud processes (Ayala et al, parts I and II, Wang et al), • laboratory and modeling studies of complex cloud processes (Malinowski et al). This collage is far from being complete but, hopefully, should give the reader a representative impression of the current state of knowledge in the field. We hope it will be useful to all scientists whose work is inspired by cloud processes. Focus on Cloud Physics Contents The development of ice in a cumulus cloud over southwest England Yahui Huang, Alan M Blyth, Philip R A Brown, Tom W Choularton,

Falkovich, Gregory; Malinowski, Szymon P.

2008-07-01

127

The Perseus Cloud  

NASA Astrophysics Data System (ADS)

The Perseus molecular cloud and its surroundings contain several regions of active or recent star formation lying within about 300 pc of the Sun (see Figure ref{FinderChart}). Roughly a dozen OB and over a thousand lower mass stars younger than 6 Myr make up the 50 pc diameter Perseus OB 2 association. Recent supernovae in the Per OB2 association drive an expanding HI supershell into the surrounding interstellar medium. A run-away star from this association, ? Persi, illuminates and ionizes a portion of this ring, producing the California Nebula (NGC 1499, Sh-2 220). The 10^4 M_{sun} Perseus molecular cloud is the closest such object actively forming large numbers of low to intermediate-mass stars. The eastern end of the cloud is associated with the 2 - 4 Myr old cluster IC 348 that contains several hundred young stars. However, the western portion of the Perseus cloud contains the most active sites of current star formation, including the 150 member NGC 1333 cluster, the small stellar aggregates associated with Barnard 1, L1448, L1455, and additional cloud cores which are producing smaller groups of young stars. Narrow-band visual wavelength surveys have led to the discovery of over a hundred individual Herbig-Haro objects. Studies of outflows in the Perseus molecular cloud have illuminated their contribution to the generation of turbulent motions in the surrounding gas, the disruption of cloud cores, and the self regulation of star formation. In this review, we cover the region of the sky from about l =3D 150°{} to 180°{} and b =3D -30°{} to 0°{}, and the young stars, clusters, and clouds which lie between 200 and 400 pc from the Sun with ages of less than about 15 Myr with an emphasis on the Perseus molecular cloud. This is the sphere of influence of the Per OB2 association. We discuss the 20°. diameter Per OB2 supershell, the OB association, its relationship to surrounding molecular gas, and on-going star formation within the Perseus molecular cloud.

Bally, J.; Walawender, J.; Johnstone, D.; Kirk, H.; Goodman, A.

2008-12-01

128

Dynamics of Finite Dust Clouds in a Magnetized Anodic Plasma  

SciTech Connect

The response to an external modulation voltage of small dust clouds confined in an anodic plasma is studied. Dust density waves are excited when the cloud is larger than a wavelength, whereas a sloshing and stretching motion is found for smaller clouds. The wave dispersion shows similarities with waveguide modes.

Piel, A.; Pilch, I.; Trottenberg, T. [Institute for Experimental and Applied Physics, Christian-Albrechts University, D-24098 Kiel (Germany); Koepke, M. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26505-6315 (United States)

2008-09-07

129

Vortices in dust clouds under microgravity: A simple explanation.  

PubMed

Clouds of dust particles in radio frequency discharges often show a periodic vortexlike motion, especially near the edges of the electrodes or near the tip of an electrostatic probe. These vortices often last as long as the discharge is powered. In a previous paper we have followed a small number of individual dust particles in a discharge under microgravity conditions, moving under the influence of forces computed by means of a self-consistent two-dimensional hydrodynamic model, and interacting via a screened Coulomb potential. The resulting motion showed the vortexlike rotation. In this paper we discuss this phenomenon in more detail, using a simplified model with harmonic forces, but extending the simulations to three dimensions. Stable vortices are observed, which show a more chaotic behavior than in the two-dimensional situation. Particles frequently jump up and down between two counterrotating vortices. The generation of the vortices can be ascribed to a nonzero rotation of the net global force vector field, which is the sum of the ion drag force, the electric force, and the thermophoretic force in case of the experiments. Comparison of experimental data with simulations using a model potential may open a way to unravel the forces inside a cloud of dust particles. PMID:14682994

Goedheer, W J; Akdim, M R

2003-10-09

130

WindCam and MSPI: two cloud and aerosol instrument concepts derived from Terra/MISR heritage  

NASA Astrophysics Data System (ADS)

The Multi-angle Imaging SpectroRadiometer (MISR) has been acquiring global cloud and aerosol data from polar orbit since February 2000. MISR acquires moderately high-resolution imagery at nine view angles from nadir to 70.5°, in four visible/near-infrared spectral bands. Stereoscopic parallax, time lapse among the nine views, and the variation of radiance with angle and wavelength enable retrieval of geometric cloud and aerosol plume heights, height-resolved cloud-tracked winds, and aerosol optical depth and particle property information. Two instrument concepts based upon MISR heritage are in development. The Cloud Motion Vector Camera, or WindCam, is a simplified version comprised of a lightweight, compact, wide-angle camera to acquire multiangle stereo imagery at a single visible wavelength. A constellation of three WindCam instruments in polar Earth orbit would obtain height-resolved cloud-motion winds with daily global coverage, making it a low-cost complement to a spaceborne lidar wind measurement system. The Multiangle SpectroPolarimetric Imager (MSPI) is aimed at aerosol and cloud microphysical properties, and is a candidate for the National Research Council Decadal Survey's Aerosol-Cloud-Ecosystem (ACE) mission. MSPI combines the capabilities of MISR with those of other aerosol sensors, extending the spectral coverage to the ultraviolet and shortwave infrared and incorporating high-accuracy polarimetric imaging. Based on requirements for the nonimaging Aerosol Polarimeter Sensor on NASA's Glory mission, a degree of linear polarization uncertainty of 0.5% is specified within a subset of the MSPI bands. We are developing a polarization imaging approach using photoelastic modulators (PEMs) to accomplish this objective.

Diner, David J.; Mischna, Michael; Chipman, Russell A.; Davis, Ab; Cairns, Brian; Davies, Roger; Kahn, Ralph A.; Muller, Jan-Peter; Torres, Omar

2008-08-01

131

A method for reciprocating motion detection in porn video based on motion features  

Microsoft Academic Search

This paper presents a new algorithm for detecting the human's reciprocating motion in pornographic videos. First, the motion vector is extracted from mpeg video stream and pretreated so that the motion features are extracted by analyzing the motion rule of the objectionable videos. Then the whole videos are detected through setting a threshold. Experimental results demonstrate that the correct recognition

Qu Zhiyi; Liu Yanmin; Liu Ying; Jiu Kang; Chen Yong

2009-01-01

132

Motion graphs  

Microsoft Academic Search

In this paper we present a novel method for creating realistic, controllable motion. Given a corpus of motion capture data, we automatically construct a directed graph called a motion graph that encapsulates connections among the database. The motion graph consists both of pieces of original motion and automatically generated transitions. Motion can be generated simply by building walks on the

Lucas Kovar; Michael Gleicher; Frederic H. Pighin

2002-01-01

133

Cloud Types  

NSDL National Science Digital Library

This table provides a quick reference to cloud types. Clouds are divided into groups mainly based on the height of the cloud's base above the Earth's surface. The table further divides the types according to group, atmospheric layer, and base height. Links to additional information are embedded in the text, and users can select beginner, intermediate, or advanced levels of difficulty. A Spanish translation is available.

134

PRESENT-DAY PLATE MOTIONS  

Microsoft Academic Search

A data set comprising 110 spread- ing rates, 78 transform fault azimuths, and 142 earthquake slip vectors has been inverted to yield a new instantaneous plate motion model, designated Relative Motion 2 (RM2). The model represents a considerable improvement over our previous estimate, RM1 (Minster et al., 1974). The mean averaging interval for the spreading rate data has been reduced

J. Bernard Minster; Thomas H. Jordan

1978-01-01

135

Present-Day Plate Motions.  

National Technical Information Service (NTIS)

A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to le...

J. B. Minster T. H. Jordan

1977-01-01

136

Force and Motion: Position and Motion  

NSDL National Science Digital Library

This Science Object is the first of four Science Objects in the Force and Motion SciPack. It provides an understanding of how changes in position and motion can affect the way objects move, focusing on constant motion (where the direction and speed remain the same) and acceleration (a change in motion due to a change in an object's direction or speed). The position of an object must be described relative to some other object while the motion of an object can be described by its direction and speed. Velocity is a measure of both an object's speed and its direction (and can be described by vectors). Learning Outcomes:� Identify the position of one object relative to the position of another object by providing the approximate distance and angles between the objects, the angles being measured from some reference line.� Define the concepts of speed and velocity.� Determine the average speed of an object given necessary information.� Describe, draw, or otherwise detail the velocity of an object given magnitude and direction.� Define acceleration.� Recognize examples of acceleration and provide examples of acceleration.� Distinguish between constant and changing motion.� Distinguish increasing speed from increasing acceleration.� Recognize that the state of rest is a state of zero speed (rather than as something fundamentally different than motion).

National Science Teachers Association (NSTA)

2006-11-01

137

Vector Voyage!  

NSDL National Science Digital Library

In this activity, students will use vector analysis to understand the concept of dead reckoning. Students will use vectors to plot their course based on a time and speed. They will then correct the positions with vectors representing winds and currents.

Integrated Teaching And Learning Program

138

Cloud Condensation Nuclei Measurements within Clouds.  

National Technical Information Service (NTIS)

Measurements of the spectra of cloud condensation nuclei (CCN) within and near the boundaries of clouds are presented. Some of the in-cloud measurements excluded the nuclei within cloud droplets (interstitial CCN) while others included all nuclei inside t...

J. G. Hudson

1984-01-01

139

Cardiac Motion Estimation from Gated Emission Computed Tomography Images  

Microsoft Academic Search

Quantitative description of the cardiac left ventricle (LV) motion is desirable to assist in detecting myocardial motion abnormalities. It has been recognized that the torsion component of the LV movement is considerably more difficult to track than its radial counterpart. We develop a motion estimation method that estimates three-dimensional (3-D) LV motion vector field (MVF) that includes the twisting motion

Jing Tang; W. Paul Segars; Benjamin M. W. Tsui

2006-01-01

140

Oort Cloud.  

National Technical Information Service (NTIS)

Views of the large-scale structure of the solar system, consisting of the Sun, the nine planets and their satellites, changed when Oort demonstrated that a gigantic cloud of comets (the Oort cloud) is located on the periphery of the solar system. The foll...

L. S. Marochnik L. M. Mukhin R. Z. Sagdeev

1991-01-01

141

Cloud Control  

ERIC Educational Resources Information Center

|Your learning curriculum needs a new technological platform, but you don't have the expertise or IT equipment to pull it off in-house. The answer is a learning system that exists online, "in the cloud," where learners can access it anywhere, anytime. For trainers, cloud-based coursework often means greater ease of instruction resulting in greater…

Weinstein, Margery

2012-01-01

142

Cloud Cover  

ERIC Educational Resources Information Center

|This article features a major statewide initiative in North Carolina that is showing how a consortium model can minimize risks for districts and help them exploit the advantages of cloud computing. Edgecombe County Public Schools in Tarboro, North Carolina, intends to exploit a major cloud initiative being refined in the state and involving every…

Schaffhauser, Dian

2012-01-01

143

Cloud Control  

ERIC Educational Resources Information Center

|For many IT shops, the cloud offers an opportunity not only to improve operations but also to align themselves more closely with their schools' strategic goals. The cloud is not a plug-and-play proposition, however--it is a complex, evolving landscape that demands one's full attention. Security, privacy, contracts, and contingency planning are…

Ramaswami, Rama; Raths, David; Schaffhauser, Dian; Skelly, Jennifer

2011-01-01

144

Position, Velocity, and Acceleration in Uniform Circular Motion  

NSDL National Science Digital Library

This applet displays the position, velocity, and acceleration vectors for an object moving in uniform circular motion. The vectors are shown on different graphs. The graphs can be set to display constant motion or they can be paused and moved through the motion step by step.

Sternin, Edward

2006-04-14

145

Magnetohydrodynamic stability of broad line region clouds  

NASA Astrophysics Data System (ADS)

Hydrodynamic stability has been a longstanding issue for the cloud model of the broad line region in active galactic nuclei. We argue that the clouds may be gravitationally bound to the supermassive black hole. If true, stabilization by thermal pressure alone becomes even more difficult. We further argue that if magnetic fields are present in such clouds at a level that could affect the stability properties, they need to be strong enough to compete with the radiation pressure on the cloud. This would imply magnetic field values of a few gauss for a sample of active galactic nuclei we draw from the literature. We then investigate the effect of several magnetic configurations on cloud stability in axisymmetric magnetohydrodynamic simulations. For a purely azimuthal magnetic field which provides the dominant pressure support, the cloud first gets compressed by the opposing radiative and gravitational forces. The pressure inside the cloud then increases, and it expands vertically. Kelvin-Helmholtz and column density instabilities lead to a filamentary fragmentation of the cloud. This radiative dispersion continues until the cloud is shredded down to the resolution level. For a helical magnetic field configuration, a much more stable cloud core survives with a stationary density histogram which takes the form of a power law. Our simulated clouds develop sub-Alfvénic internal motions on the level of a few hundred km s-1.

Krause, Martin; Schartmann, Marc; Burkert, Andreas

2012-10-01

146

Coriolis effects and motion sickness modelling  

Microsoft Academic Search

Coriolis effects are notorious in relation to disorientation and motion sickness in aircrew. A review is provided of experimental data on these Coriolis effects, including the modulatory effects of adding visual or somatosensory rotatory motion information. A vector analysis of the consequences of head movements during somatosensory, visual and\\/or vestibular rotatory motion stimulation revealed that the more the sensed angular

Willem Bles

1998-01-01

147

An Inexpensive Mechanical Model for Projectile Motion  

ERIC Educational Resources Information Center

|As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the…

Kagan, David

2011-01-01

148

Ice in Volcanic Clouds  

NASA Astrophysics Data System (ADS)

It is widely recognized that lightning activity in thunderstorm clouds is associated with ice in the clouds. In volcanic plumes the lower electrical discharges near the vent are clearly not associated with ice; however, the electrical discharges from the upper volcanic clouds very likely are associated with ice. There is ample water in volcanic plumes and clouds. The explosive volcanic eruption is produced by volatile components in the rising magma. Researchers estimate that the water content of the volatiles is up to 99% by mole; other gases are mainly sulfur and chlorine species. These volatiles carry with them a wide range of hot magma melts and solids, importantly silicate particles and tephra. The more massive components fall out near the vent carrying with them much of the heat from the plume; these large components are not in thermodynamic equilibrium with the gases, ash, and lapilli; thus the heat removed does not lower the temperature of the materials carried aloft in the plume. Upward motion is initially provided by the thrust from the volcanic eruption, then by buoyancy of the hot plume. The rising plume is cooled by entrainment of environmental air, which contains water, and by adiabatic expansion; the plume transitions into a volcanic cloud. Further lifting and cooling produces supercooled water droplets (T ~ -5 C) in a limited zone (z ~ 9 km) before the fast updraft (~ 60 m/s) rapidly transforms them into ice. Computer models of volcanic clouds that include water and ice microphysics indicate that the latent heat of condensation is not significant in cloud dynamics because it occurs in a region where buoyancy is provided by the original hot plume material. The latent heat of ice formation occurs at higher and colder levels and seems to contribute to the final lifting of the cloud top by ~1.5km. Laboratory results indicate that the fine silicate ash particles, which are abundant, are good ice nuclei, IN. Because of the abundance of the silicate ash, modelers conclude that there are many small ice particles in a volcanic clouds compared to thunderstorm clouds where the scarcity of IN produce fewer but larger ice particles. Another microphysical difference is that in the water phase (drops or ice surface) adsorption of sulfur and chlorine gases is enhanced and the freezing temperature lowered. During diffusion growth of ice particles sulfur dioxide can be incorporated in the ice. The sulfur dioxide sequestered by the ice can be converted to sulfate and transported into the stratosphere and released when the ice sublimates. Do these microphysical differences significantly alter the electrical charging mechanisms that exist in thunderstorm clouds? Observations of the lightning discharges associated with the upper regions of volcanic clouds seem to indicate that the charging mechanisms are essentially the same.

Few, A. A.

2010-12-01

149

Cloud Formation  

NASA Astrophysics Data System (ADS)

Cloud formation is crucial to the heritage of modern physics, and there is a rich literature on this important topic.1 In 1927, Charles T.R. Wilson was awarded the Nobel Prize in physics for applications of the cloud chamber.2 Wilson was inspired to study cloud formation after working at a meteorological observatory on top of the highest mountain in Scotland, Ben Nevis, and testified near the end of his life, ``The whole of my scientific work undoubtedly developed from the experiments I was led to make by what I saw during my fortnight on Ben Nevis in September 1894.''3 To form clouds, Wilson used the sudden expansion of humid air.4 Any structure the cloud may have is spoiled by turbulence in the sudden expansion, but in 1912 Wilson got ion tracks to show up by using strobe photography of the chamber immediately upon expansion.5 In the interim, Millikan's study in 1909 of the formation of cloud droplets around individual ions was the first in which the electron charge was isolated. This study led to his famous oil drop experiment.6 To Millikan, as to Wilson, meteorology and physics were professionally indistinct. With his meteorological physics expertise, in WWI Millikan commanded perhaps the first meteorological observation and forecasting team essential to military operation in history.7 But even during peacetime meteorology is so much of a concern to everyone that a regular news segment is dedicated to it. Weather is the universal conversation topic, and life on land could not exist as we know it without clouds. One wonders then, why cloud formation is never covered in physics texts.

Graham, Mark Talmage

2004-05-01

150

Cloud-tracked winds from Pioneer Venus OCPP images  

NASA Astrophysics Data System (ADS)

Results are presented on the analysis of the Pioneer Venus Orbiter Cloud Photopolarimeter (OCPP) UV images, covering 80-day periods from 1979 to 1985. The analysis provides a method for determining wind speeds at the cloud level, from the motions of cloud UV features. Data used for tracking the cloud feature motions are described along with the analysis method. The results identified four wave modes: a diurnal solar tide, a semidiurnal solar tide, a '4-day equatorial' wave, and a '5-day midlatitude' wave. The features of these wave modes are described.

Rossow, William B.; del Genio, Anthony D.; Eichler, Timothy

1990-09-01

151

CLOUD CONDENSATION NUCLEI MEASUREMENTS WITHIN CLOUDS  

EPA Science Inventory

Measurements of the spectra of cloud condensation nuclei (CCN) within and near the boundaries of clouds are presented. Some of the in-cloud measurements excluded the nuclei within cloud droplets (interstitial CCN) while others included all nuclei inside the cloud (total CCN). The...

152

Motion Commotion  

NSDL National Science Digital Library

Students learn why and how motion occurs and what governs changes in motion, as described by Newton's three laws of motion. They gain hands-on experience with the concepts of forces, changes in motion, and action and reaction. In an associated literacy activity, students design a behavioral survey and learn basic protocol for primary research, survey design and report writing.

Integrated Teaching And Learning Program

153

Seeing Motion  

NSDL National Science Digital Library

Explore your own straight-line motion using a motion sensor to generate distance versus time graphs of your own motion. Learn how changes in speed and direction affect the graph, and gain an understanding of how motion can be represented on a graph.

Consortium, The C.

2011-12-11

154

Perception of Motion in Statistically-Defined Displays.  

National Technical Information Service (NTIS)

Though motion perception does depend upon spatially local processes, under certain circumstances global processes make an important contribution. For example, the human visual system can integrate different, spatially-intermingled motion vectors into a gl...

R. Sekuler

1988-01-01

155

Efficient motion field representation using JBIG approach for video compression  

NASA Astrophysics Data System (ADS)

In this study, a simple and efficient scheme to improve the compression ratio of the block--based motion fields in the video compressing is proposed. In the proposed scheme, each motion field is represented by a small set of coded motion vectors and a binary bitmap. Some of the motion vectors in a motion field, named as significant motion vectors (SMVs), have the property of being significantly different from the motion vectors of their spatial or temporal adjacent blocks. Instead of coding all the motion vectors in a motion field, only the SMVs need to be coded in the proposed scheme. For each block in a frame, one bit, corresponding to its position on the binary bitmap, is used to record if the motion vector is significant or not. And then, the joint bilevel image experts group (JBIG) image coding standard is applied on the bitmap to improve the bit-rate. The experimental results reveal that more than half of the motion vectors are non--significant and can be omitted on coding procedure. Although there exists an overhead of JBIG coded binary bitmap, the coding improvement ratio of the proposed scheme is over 40% on average when comparing with the conventional variable length coding (VLC) scheme.

Tseng, Shou-Yi

2002-09-01

156

Cloud Computing Fundamentals  

Microsoft Academic Search

\\u000a In the introductory chapter we define the concept of cloud computing and cloud services, and we introduce layers and types\\u000a of cloud computing. We discuss the differences between cloud computing and cloud services. New technologies that enabled cloud\\u000a computing are presented next. We also discuss cloud computing features, standards, and security issues. We introduce the key\\u000a cloud computing platforms, their

Borko Furht

2010-01-01

157

Development of a radiative cloud parameterization scheme of stratocumulus and stratus clouds which includes the impact of CCN on cloud albedo  

SciTech Connect

The objective of this research is to develop a parameterization scheme that is able to dispose or predict changes in stratocumulus cloud cover, atmospheric boundary layer (ABL) stability, liquid water paths (LWPs), and cloud albedo due to changes in sea-surface temperatures, large scale vertical motion and wind shear, and cloud condensation nuclei (CCN). The motivation for developing such a parameterization scheme is that it is hypothesized that anthropogenic sources of CCN can result in increased concentrations of cloud droplets. The higher concentrations of CCN result in higher concentrations of cloud droplets, thereby enhancing cloud albedo which in the absence of other effects will induce a climate forcing opposed to that associated with ``Greenhouse`` warming. As a result of the complicated interactions between cloud microstructure, cloud macrostructure, and cloud radiative transfer, only a limited range of clouds are susceptible to changes in CCN concentrations causing changes in cloud albedo. It is the intent of this research to determine the range of cloud types that are susceptible to albedo changes by anthropogenic CCN and incorporate that information into a cloud parameterization scheme.

Cotton, W.R.

1994-01-18

158

Cloud level winds from the Venus Express Monitoring Camera imaging  

NASA Astrophysics Data System (ADS)

Six years of continuous monitoring of Venus by European Space Agency's Venus Express orbiter provides an opportunity to study dynamics of the atmosphere our neighbor planet. Venus Monitoring Camera (VMC) on-board the orbiter has acquired the longest and the most complete so far set of ultra violet images of Venus. These images enable a study the cloud level circulation by tracking motion of the cloud features. The highly elliptical polar orbit of Venus Express provides optimal conditions for observations of the Southern hemisphere at varying spatial resolution. Out of the 2300 orbits of Venus Express over which the images used in the study cover about 10 Venus years. Out of these, we tracked cloud features in images obtained in 127 orbits by a manual cloud tracking technique and by a digital correlation method in 576 orbits. Total number of wind vectors derived in this work is 45,600 for the manual tracking and 391,600 for the digital method. This allowed us to determine the mean circulation, its long-term and diurnal trends, orbit-to-orbit variations and periodicities. We also present the first results of tracking features in the VMC near-IR images. In low latitudes the mean zonal wind at cloud tops (67 ± 2 km following: Rossow, W.B., Del Genio, A.T., Eichler, T. [1990]. J. Atmos. Sci. 47, 2053-2084) is about 90 m/s with a maximum of about 100 m/s at 40-50°S. Poleward of 50°S the average zonal wind speed decreases with latitude. The corresponding atmospheric rotation period at cloud tops has a maximum of about 5 days at equator, decreases to approximately 3 days in middle latitudes and stays almost constant poleward from 50°S. The mean poleward meridional wind slowly increases from zero value at the equator to about 10 m/s at 50°S and then decreases to zero at the pole. The error of an individual measurement is 7.5-30 m/s. Wind speeds of 70-80 m/s were derived from near-IR images at low latitudes. The VMC observations indicate a long term trend for the zonal wind speed at low latitudes to increase from 85 m/s in the beginning of the mission to 110 m/s by the middle of 2012. VMC UV observations also showed significant short term variations of the mean flow. The velocity difference between consecutive orbits in the region of mid-latitude jet could reach 30 m/s that likely indicates vacillation of the mean flow between jet-like regime and quasi-solid body rotation at mid-latitudes. Fourier analysis revealed periodicities in the zonal circulation at low latitudes. Within the equatorial region, up to 35°S, the zonal wind show an oscillation with a period of 4.1-5 days (4.83 days on average) that is close to the super-rotation period at the equator. The wave amplitude is 4-17 m/s and decreases with latitude, a feature of the Kelvin wave. The VMC observations showed a clear diurnal signature. A minimum in the zonal speed was found close to the noon (11-14 h) and maxima in the morning (8-9 h) and in the evening (16-17 h). The meridional component peaks in the early afternoon (13-15 h) at around 50°S latitude. The minimum of the meridional component is located at low latitudes in the morning (8-11 h). The horizontal divergence of the mean cloud motions associated with the diurnal pattern suggests upwelling motions in the morning at low latitudes and downwelling flow in the afternoon in the cold collar region.

Khatuntsev, I. V.; Patsaeva, M. V.; Titov, D. V.; Ignatiev, N. I.; Turin, A. V.; Limaye, S. S.; Markiewicz, W. J.; Almeida, M.; Roatsch, Th.; Moissl, R.

2013-09-01

159

Mystery clouds  

NASA Astrophysics Data System (ADS)

‘Mystery clouds,’ recently observed to cover the earth's northern hemisphere, have caused speculation as to their origin. Apparently, they could be fallout from a nuclear explosion or from a meteor impact. A more likely probability is that the clouds are layers of fine particulates, probably a sulfuric acid water mist, released from volcanic eruptions. M.P. McCormick of the Langley Research Center, speaking in regard to its possible volcanic origin, stated ‘It had to be one that had little local damage but moved material high enough to get into the stratosphere, where it [could] travel around the world. Historically, information on the height of volcanic eruptions has proven unreliable due to, among other things, the difficulty of accurately observing them at night or through cloud cover.’

Bell, Peter M.

160

CLOUD CHEMISTRY.  

SciTech Connect

Clouds present substantial concentrations of liquid-phase water, which can potentially serve as a medium for dissolution and reaction of atmospheric gases. The important precursors of acid deposition, SO{sub 2} and nitrogen oxides NO and NO{sub 2} are only sparingly soluble in clouds without further oxidation to sulfuric and nitric acids. In the case of SO{sub 2} aqueous-phase reaction with hydrogen peroxide, and to lesser extent ozone, are identified as important processes leading to this oxidation, and methods have been described by which to evaluate the rates of these reactions. The limited solubility of the nitrogen oxides precludes significant aqueous-phase reaction of these species, but gas-phase reactions in clouds can be important especially at night.

SCHWARTZ,S.E.

2001-03-01

161

A dust cloud around Pluto and Charon  

Microsoft Academic Search

We suggest that Pluto and Charon are immersed in a tenuous dust cloud. The cloud consists of ejecta from Pluto and—especially— Charon, released from their surfaces by impacts of micrometeoroids originating from Edgeworth-Kuiper belt objects. The motion of the ejected grains is dominated by the gravity of Pluto and Charon, which determines a pear-shape of the densest part of the

K.-U. Thiessenhusena; A. V. Krivovb; H. Kr; E. Gr

162

Cloud Formation  

NSDL National Science Digital Library

This Classroom Connectors lesson plan teaches students how clouds are formed through the condensation of water vapor. This includes learning about climate types and how they change, the greenhouse effect, how clouds affect weather and climate, and condensation. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

163

Using Low-Level Motion to Estimate Gait Phase  

Microsoft Academic Search

This paper presents a method that is capable of robustly estimating gait phase of a human walking using the motion of a sparse cloud of feature points extracted using a standard feature tracker. We first learn statistical motion models of the trajectories we would expect to observe for each of the main limbs. By comparing the motion of the tracked

Ben Daubney; David Gibson; Neill W. Campbell

2008-01-01

164

Estimating Gait Phase using Low-Level Motion  

Microsoft Academic Search

This paper presents a method that is capable of robustly estimating gait phase of a human walking from a sequence of images using only low-level motion. The approach we adopt is first to learn statistical motion models of the trajectories we would expect to observe for each of the main limbs. We then extract a sparse cloud of motion features

Ben Daubney; David Gibson; Neill Campbell

2008-01-01

165

Shapes of Bubbles and Drops in Motion.  

ERIC Educational Resources Information Center

|Explains the shape distortions that take place in fluid packets (bubbles or drops) with steady flow motion by using the laws of Archimedes, Pascal, and Bernoulli rather than advanced vector calculus. (WRM)|

O'Connell, James

2000-01-01

166

Motion Sickness  

MedlinePLUS

... alone. Motion sickness, whether on boats or in planes, cars or amusement rides, can strike anyone. 290229 ... alone. Motion sickness, whether on boats or in planes, cars or amusement rides, can strike anyone. Take ...

167

Cloud computing.  

PubMed

In this bimonthly series, the author examines how nurse educators can use Internet and Web-based technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes how cloud computing can be used in nursing education. PMID:22157990

Wink, Diane M

168

Motion warping  

Microsoft Academic Search

We describe a simple technique for editing captured or keyframed animation based on warping of the motion parameter curves. The animator interactively defines a set of keyframe-like constraints which are used to derive a smooth deformation that preserves the fine structure of the original motion. Motion clips are combined by overlapping and blending of the parameter curves. We show that

Andrew P. Witkin; Zoran Popovic

1995-01-01

169

Motion Constants  

Microsoft Academic Search

A Bose condensate of electrons may exist in nickel hydrogen and palladium hydrogen systems. The motion constants associated with the gravitational and nuclear forces motion tend toward the electromagnetic in these systems. The change in the motion constants produces unexpected gravitomagnetic and nuclear affects.

Frank Znidarsic

2000-01-01

170

Giant Molecular Clouds in the Magellanic Clouds  

Microsoft Academic Search

We review the present knowledge of Giant molecular clouds in the Large and Small Magellanic Cloud. In particular we discuss the molecular cloud properties and its relation to massive star formation. Additionally we present recent results of the 1.2mm continuum observations with SIMBA towards molecular cloud and star forming regions and its implications on dust properties on these low metallicity

M. Rubio

2004-01-01

171

Giant Molecular Clouds in the Magellanic Clouds  

NASA Astrophysics Data System (ADS)

We review the present knowledge of Giant molecular clouds in the Large and Small Magellanic Cloud. In particular we discuss the molecular cloud properties and its relation to massive star formation. Additionally we present recent results of the 1.2mm continuum observations with SIMBA towards molecular cloud and star forming regions and its implications on dust properties on these low metallicity galaxies.

Rubio, M.

2004-12-01

172

Navigational Vectors  

NSDL National Science Digital Library

This is a high school instructional unit that features nine lessons relating to vectors. Students build understanding of vector properties as they learn airplane navigation. Problem-based learning activities include reading real-time weather maps, tracking airplanes flying in U.S. skies, calculating vector components, analyzing effects of wind velocity, and completing training segments similar to a private pilot certification program. Participants have access to help from experts at the Polaris Career Center. Comprehensive teacher guides, student guides, reference materials, and assessments are included. This resource was developed by the Center for Innovation in Science and Engineering Education (CIESE). Participation is cost-free; additional options are available for registered users.

173

Simulation of Spaceborne Doppler Radar Observations of Clouds  

Microsoft Academic Search

Space-borne Doppler radar observations of clouds are scientifically very interesting, but the correct interpretation of the measurements is challenging. Global observations of vertical velocity in cloud systems in many different climate zones will improve our understanding of large-scale convective motions and cloud microphysics. Unfortunately, observed Doppler speeds are a complex weighted average over all line-of-sight velocities within the radar's field-of-view.

N. Schutgens

2006-01-01

174

Vector carpets  

SciTech Connect

Previous papers have described a general method for visualizing vector fields that involves drawing many small ``glyphs`` to represent the field. This paper shows how to improve the speed of the algorithm by utilizing hardware support for line drawing and extends the technique from regular to unstructured grids. The new approach can be used to visualize vector fields at arbitrary surfaces within regular and unstructured grids. Applications of the algorithm include interactive visualization of transient electromagnetic fields and visualization of velocity fields in fluid flow problems.

Dovey, D.

1995-03-22

175

Vector Calculus  

NSDL National Science Digital Library

This is a series of lectures, authored by Chris Tisdell of the University of New South Wales, for MATH2111 "Higher Several Variable Calculus" and "Vector Calculus", which is a 2nd-year mathematics subject taught at UNSW, Sydney. This playlist provides a shapshot of some lectures presented in Session 1, 2009. These lectures focus on presenting vector calculus in an applied and engineering context, while maintaining mathematical rigour. Thus, this playlist may be useful to students of mathematics, but also to those of engineering, physics and the applied sciences. There is an emphasis on examples and also on proofs.

Tisdell, Chris

2010-12-16

176

Plate motion  

SciTech Connect

The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

Gordon, R.G. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

177

Angular Motion of Spinning Almost Symmetric Missiles.  

National Technical Information Service (NTIS)

An almost symmetric missile is a missile whose zero-spin pitch and yaw frequencies are 'nearly' equal. The angular motion of a spinning almost symmetric missile can be described by five rotating modal vectors. Two of these vectors vanish when the frequenc...

C. H. Murphy

1978-01-01

178

Equations of Motion of a Rigid Projectile.  

National Technical Information Service (NTIS)

The basic vector equations of motion of a rigid body are described, and an aerodynamic forcemoment system is developed. The vector forces and moments due to gravity and rotation of the earth are added to the system. Forces and moments produced by a rocket...

R. F. Lieske R. L. McCoy

1964-01-01

179

Motion-based motion deblurring.  

PubMed

Motion blur due to camera motion can significantly degrade the quality of an image. Since the path of the camera motion can be arbitrary, deblurring of motion blurred images is a hard problem. Previous methods to deal with this problem have included blind restoration of motion blurred images, optical correction using stabilized lenses, and special cmos sensors that limit the exposure time in the presence of motion. In this paper, we exploit the fundamental trade off between spatial resolution and temporal resolution to construct a hybrid camera that can measure its own motion during image integration. The acquired motion information is used to compute a point spread function (psf) that represents the path of the camera during integration. This psf is then used to deblur the image. To verify the feasibility of hybrid imaging for motion deblurring, we have implemented a prototype hybrid camera. This prototype system was evaluated in different indoor and outdoor scenes using long exposures and complex camera motion paths. The results show that, with minimal resources, hybrid imaging outperforms previous approaches to the motion blur problem. We conclude with a brief discussion on how our ideas can be extended beyond the case of global camera motion to the case where individual objects in the scene move with different velocities. PMID:18579930

Ben-Ezra, Moshe; Nayar, Shree K

2004-06-01

180

Mathematical description of rotary motion  

Microsoft Academic Search

A mathematical description of the rotary motion of a solid is proposed on the basis of a multiplicative integral. As a preliminary, the representation of the angular-velocity vector in spherical coordinate systems and the conversion matrix corresponding to rotation of the coordinate system by a specified angle around an axis with specified orientation are discussed.

B. A. Okhrimenko

1995-01-01

181

Estimating Cloud Cover  

ERIC Educational Resources Information Center

The purpose of this activity was to help students understand the percentage of cloud cover and make more accurate cloud cover observations. Students estimated the percentage of cloud cover represented by simulated clouds and assigned a cloud cover classification to those simulations. (Contains 2 notes and 3 tables.)

Moseley, Christine

2007-01-01

182

Successive elimination algorithm for motion estimation  

Microsoft Academic Search

The correspondence presents a fast exhaustive search algorithm for motion estimation. The basic idea is to obtain the best estimate of the motion vectors by successively eliminating the search positions in the search window and thus decreasing the number of matching evaluations that require very intensive computations. Simulation results demonstrate that although the performance of the proposed algorithm is the

Wenhua Li; Ezzatollah Salari

1995-01-01

183

Motion field interpolation for frame rate conversion  

Microsoft Academic Search

Frame rate conversion is essential for the exchange of video material between different industries and applications. Motion compensated interpolation (MCI) has been shown to provide good frame rate conversion results. Conventional MCI methods estimate one motion vector per block of the interpolated frame. The main disadvantage of such methods are the blocking artefacts that occur at the boundaries of interpolated

Mohammed E. Al-mualla

2003-01-01

184

Intermediate Mechanics Tutorials: Simple Harmonic Motion  

NSDL National Science Digital Library

This set of tutorial materials covers the topic of simple harmonic motion. Students examine qualitatively and quantitatively the motion of a simple harmonic oscillator, as exemplified by a mass attached to an ideal spring. There are two tutorials, one using motion graphs and one using vectors, to describe the motion. Students analyze and solve the differential equations of motion to develop an understanding of the physical parameters in the problem. This material also includes a pretest, example homework, and test questions. This is part of a large collection of similar tutorial materials in intermediate classical mechanics.

Wittmann, Michael C.; Ambrose, Bradley S.

2009-03-31

185

Magical Motion  

NSDL National Science Digital Library

Students watch video clips from the October Sky and Harry Potter and the Sorcerer's Stone movies to see examples of projectile motion. Then they explore the relationships between displacement, velocity and acceleration, and calculate simple projectile motion. The objective of this activity is to articulate concepts related to force and motion through direct immersive interaction based on "The Science Behind Harry Potter" theme. Students' interest is piqued by the use of popular culture in the classroom.

University Of Houston

186

Animating Motion  

NSDL National Science Digital Library

This lesson challenges students to apply their knowledge of object motion by animating sequences of hand-rendered pictures that model a set of physical conditions. The challenges include animating the orbital motion of planets and satellites, the effects of gravity on a falling body, and motions of objects in inertial (moving) frames of reference. The lesson was created by a high school physics teacher to help learners build quantitative reasoning skills in preparation for understanding kinematics.

Latham, Ted

2004-07-16

187

Fusion of LIDAR Data and Large-scale Vector Maps for Building Reconstruction  

Microsoft Academic Search

LIDAR data contains plenty of height information, while vector maps preserve accurate building boundaries. From the viewpoint of data fusion, we integrate LIDAR data and large-scale vector maps to perform building modeling. The proposed scheme comprises six major steps: (1) preprocessing of LIDAR data and vector maps, (2) extraction of point clouds that belong to a building, (3) construction of

Liang-Chien Chen; Chih-Yi Kuo; Jiann-Yeou Rau; Chi-Heng Hsieh

188

Pion-cloud effects on the electromagnetic properties of nucleons in a quark model  

SciTech Connect

This paper reports that incorporating corrections for the center-of-mass motion and pion-cloud effects the nucleon electromagnetic form factors G[sup N][sub E.M] (q[sup 2]) are computed in an independent quark model based on the Dirac equation with a confining potential V[sub q](r) = (1 + [gamma][sup 0]) a 1n (r/b). The static quantities like magnetic moment [mu]n, charge radius (r[sup 2]) [sup 1/2][sub N] and axial vector coupling constant (g[sub A])[sub n [r arrow] pev] of the nucleons computed in this model are in reasonable agreement with the experiment. The pseudoscalar and the pseudovector pion-nucleon coupling constants are obtained as g[sub NN[pi

Barik, N. (Utkal Univ., Bhubaneswar (India). Dept. of Physics); Jena, S.N. (Berhampur Univ. (India). Dept. of Physics); Rath, D.P. (Dept. of Physics, Aska Science College, ASKA-761110, Orissa (India))

1992-10-30

189

Bad Clouds  

NSDL National Science Digital Library

This information is designed to belie the misconception that the capacity of air to hold water vapor is temperature dependent and that air can become saturated with water vapor. The temperature of a cloud droplet or ice crystal will be nearly the same as that of the air, so people imagine that somehow the air was to blame. But, if the other gases of the air were removed, leaving everything else the same, condensation and evaporation would proceed as before and the air was irrelevant to the behavior of the water molecules. It is therefore not correct to assign the behavior of water to an invented holding capacity of the air.

Fraser, Alistair

190

Multirate image sequence coding with quadtree segmentation and backward motion compensation  

Microsoft Academic Search

In this paper, we present a new image sequence coding scheme which employs backward motion compensation, quadtree segmentation, and pruned tree-structured vector quantization. Based only on the previous reconstructed frames, the backward motion compensation technique eliminates the necessity to transmit the motion displacement vectors as side information, and thus achieves a bit rate saving. Quadtree segmentation is used to exploit

Ligang Lu; William A. Pearlman

1992-01-01

191

The adjustment of mantle plumes to changes in plate motion  

Microsoft Academic Search

The relative motion of hotspots and lithospheric plates implies a velocity shear in the underlying mantle, causing horizontal advection of mantle plumes as they rise toward the lithosphere. Consequent tilting of plumes parallel to the direction of plate motion indicates that plumes must undergo a period of readjustment after the velocity vector for plate motion is altered. Thus the shape

Ross W. Griffiths; Mark A. Richards

1989-01-01

192

Visual simulation of clouds  

Microsoft Academic Search

Clouds present serious problems to standard computer image generation techniques because clouds do not have well-defined surfaces and boundaries. In addition, clouds contain varying degrees of translucence, and their amorphous structure can change with time. Although several approaches to cloud simulation have produced impressive results, they have relied on complex mathematical models which produce high computation costs for a single

Geoffrey Y. Gardner

1985-01-01

193

Cloud Computing hosting  

Microsoft Academic Search

Cloud Computing is a paradigm in which data, applications or software are accessed over a network. This network of servers is called as “Cloud”. Using a client such as desktops, entertainment centers, tablet computers, notebooks, wall computers, handhelds etc, users can reach into the cloud for resources as they need them. Cloud computing is on-demand access to virtualized IT resources

Lixin Fu; C. Gondi

2010-01-01

194

The Cloud Appreciation Society  

NSDL National Science Digital Library

The Cloud Appreciation Society believes that "clouds are Nature's poetry" and, therefore, "pledges to fight 'blue-sky thinking'." Visitors can find out about the latest cloud related news and events. The website offers a forum for users to ask cloud-related questions and communicate with other cloud enthusiasts. Anyone in the UK can join the society for free and membership will soon be expanding to other areas of the world. Everyone should check out the numerous fascinating pictures in the cloud gallery. Individuals can also contribute their cloud photographs to the continually growing collection. This site is also reviewed in the March 4, 2005_NSDL Physical Sciences Report_.

195

Elementary GLOBE: Cloud Fun  

NSDL National Science Digital Library

A learning activity for the "Do You Know That Clouds Have Names?" book in the Elementary GLOBE series. Each student will be given the opportunity to create their own cumulus cloud out of white paper and mount it on blue paper. Students will also complete the Cloud Fun Student Activity Sheet that includes a description of the cloud and what the weather was like on the day the cloud was observed. The purpose of the activity is to help students identify cumulus clouds and observe the weather conditions on days that they see cumulus clouds. Students will learn about a cumulus cloud's shape and appearance, how to verbally describe cumulus clouds, and what the weather is generally like when these clouds appear in the sky.

2008-12-01

196

Clouds and climate change  

NASA Astrophysics Data System (ADS)

As concern grows over the possibility of altering the Earth's climate, a major uncertainty exists in computer models used to study the Earth's atmosphere, regarding our current understanding of clouds and our ability to simulate their effect on climate. A number of recent observations and computer simulation studies, however, have shed light on the important role of clouds in determining the present and future climate of our atmosphere.Data from the National Aeronautics and Space Administration's (NASA's) Earth Radiation Budget Experiment have been used to obtain an accurate picture of how clouds affect our present global climate system [Ramanathan, 1989]. The effect of clouds on solar and thermal radiation entering and leaving our climate is known as cloud forcing. Low clouds generally cool the Earth's surface, while high clouds warm the climate system. For the entire planet, however, the cooling effect of low clouds is stronger than the warming effect from high clouds, so that overall, clouds cool the climate.

Kiehl, Jeffrey T.

197

Fault Motion  

NSDL National Science Digital Library

This collection of animations provides elementary examples of fault motion intended for simple demonstrations. Examples include dip-slip faults (normal and reverse), strike-slip faults, and oblique-slip faults.

198

Wave Motion  

NSDL National Science Digital Library

This site from Carl Nave at Georgia State University presents a discussion of wave motion. The site explains the velocity of idealized ocean waves and details the measurement of large waves aboard the USS Ramapo.

Carl R. (Rod) Nave; University, Georgia S.

199

Motion Sickness  

MedlinePLUS

... senses movement by getting signals from your inner ears, eyes, muscles and joints. When it gets signals ... example, down below on a boat, your inner ear senses motion, but your eyes cannot tell you ...

200

CERES CLoud Effects  

NSDL National Science Digital Library

This computer-generated animation depicts the Clouds and the Earth's Radiant Energy System (CERES) instrument in operation. CERES measures the energy at the top of the atmosphere and estimates energy levels in the atmosphere and at the Earth's surface. Using information from very high resolution cloud-imaging instruments on the same spacecraft, CERES also will determine cloud properties, including cloud amount, altitude, thickness, and the size of the cloud particles.

1997-06-06

201

Motion trajectories and object properties influence perceived direction of motion.  

PubMed

Judging the motion of objects is a fundamental task that the visual system executes in everyday life in order for us to navigate and interact safely with our surroundings. A number of strategies have been suggested to explain how the visual system uses motion information from different points of an object to compute veridical directions of motion. These include combining ambiguous signals from object contours via a vector summation (VS) or intersection of constraints (IOC) calculation, pooling information using a maximum likelihood or tracking object features. We measured the perceived direction of motion for a range of cross-shaped stimuli (composed of two superimposed lines) to test how accurately humans perceive their motion and compared data to predictions from these strategies. Crosses of different shapes (defined by the angle between the component lines) translated along 16 directions of motion with constant speed. The crosses either moved along one of their symmetry axes (balanced conditions with line components equidistant to the direction of motion) or had their symmetry axis tilted relative to the motion (unbalanced conditions) Data show reproducible differences between observers, including occasional bimodal behaviour, and exhibit the following common patterns. There is a general dependence on direction of motion: For all conditions, when motion is along cardinal axes (horizontal and vertical), perception is largely veridical. For non-cardinal directions, biases are typically small (<10deg) when crosses are balanced but large biases occur (?30deg) when crosses are tilted relative to their direction of motion. Factors influencing the pattern of biases are the shape and tilt of the cross as well as the proximity of its direction of motion to cardinal axes. The dependence of the biases on the direction of motion is inconsistent with any isotropic mechanisms including VS, IOC, maximum likelihood or feature tracking. Instead, perception is biased by a number of intrinsic properties of the cross and external references. The strength of these cues depends on the type, with elongation producing the strongest weight, and their proximity to the direction of motion. This suggests that the visual system may rely on a number of static cues to improve the known low precision for non-cardinal directions of motion, a process which can, however, result in large perceptual biases in certain circumstances. PMID:23911768

Magnussen, Camilla M; Orbach, Harry S; Loffler, Gunter

2013-07-31

202

Cloud and aerosol effects on radiation in deep convective clouds: comparison with warm stratiform clouds  

Microsoft Academic Search

Cloud and aerosol effects on radiation in two contrasting cloud types, a deep convective mesoscale cloud ensemble (MCE) and warm stratocumulus clouds, are simulated and compared. At the top of the atmosphere, 45 81% of shortwave cloud forcing (SCF) is offset by longwave cloud forcing (LCF) in the MCE, whereas warm stratiform clouds show the offset of less than ~20%.

S. S. Lee; L. J. Donner; V. T. J. Phillips

2008-01-01

203

Aerosol-Cloud Interactions Control of Earth Radiation and Latent Heat Release Budgets  

NASA Astrophysics Data System (ADS)

Aircraft observations and model simulations show that cloud development is strongly modulated by the impact of cloud-aerosol interactions on precipitation forming processes. New insights into the mechanisms by which aerosols dominate the cloud cover of marine shallow clouds suggest that feedbacks between the cloud microstructure and cloud dynamics through precipitation processes play a major role in determining when a solid cloud cover will break up into a field of trade wind cumulus. Cloud-aerosol interactions dominate not only the dynamics of marine shallow clouds, but also the lifetime and the vertical disposition of latent heat of deep convective clouds over ocean and even more strongly over land. Recent coincident satellite measurements of aerosols and cloud properties quantify the aerosol effects on cloud cover and radiative forcing on regional and global scales. The shapes of the satellite retrieved relations between aerosols and cloud properties are consistent with the suggested ways by which aerosols affect clouds via precipitation processes, particularly by affecting the intensity of the cloud vertical air motions and its vertical development.

Rosenfeld, D.

2006-08-01

204

Cloud microphysical budget associated with torrential rainfall during the landfall of severe tropical storm Bilis (2006)  

NASA Astrophysics Data System (ADS)

Effects of vertical wind shear, radiation, and ice clouds on cloud microphysical budget associated with torrential rainfall during landfall of severe tropical storm Bilis (2006) are investigated by using a series of analysis of two-day grid-scale sensitivity experiment data. When upper-tropospheric upward motions and lower-tropospheric downward motions occur on 15 July 2006, the removal of vertical wind shear and ice clouds increases rainfall contributions from the rainfall type (CM) associated with positive net condensation and hydrometeor loss/convergence, whereas the exclusion of cloud radiative effects and cloud-radiation interaction reduces rainfall contribution from CM. The elimination of vertical wind shear and cloud-radiation interaction increases rainfall contribution from the rainfall type (Cm) associated with positive net condensation and hydrometeor gain/divergence, but the removal of cloud radiative effects and ice clouds decreases rainfall contribution from Cm. The enhancements in rainfall contribution from the rainfall type (cM) associated with negative net condensation and hydrometeor loss/convergence are caused by the exclusion of cloud radiative effects, cloud-radiation interaction and ice clouds, whereas the reduction in rainfall contribution from cM results from the removal of vertical wind shear. When upward motions appear throughout the troposphere on 16 July, the exclusion of all these effects increases rainfall contribution from CM, but generally decreases rainfall contributions from Cm and cM.

Wang, Donghai; Liu, Ying; Zhu, Ping; Yin, Jinfang; Li, Xiaofan; Tao, Wei-Kuo

2013-04-01

205

Vector Addition Model  

NSDL National Science Digital Library

The Vector Addition model allows the user to practice vector addition of two vectors in two dimensions. You are given the magnitude and direction of the two vectors, and your goal is to fill in the nine values in the table (showing the x-component, y-component, and length) of the two vectors, and the resultant vector that is the sum of the first two vectors. The Vector Addition was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

206

Characterization of free breathing patterns with 5D lung motion model  

SciTech Connect

Purpose: To determine the quiet respiration breathing motion model parameters for lung cancer and nonlung cancer patients. Methods: 49 free breathing patient 4DCT image datasets (25 scans, cine mode) were collected with simultaneous quantitative spirometry. A cross-correlation registration technique was employed to track the lung tissue motion between scans. The registration results were applied to a lung motion model: X-vector=X-vector{sub 0}+{alpha}-vector{beta}-vector f, where X-vector is the position of a piece of tissue located at reference position X-vector{sub 0} during a reference breathing phase (zero tidal volume v, zero airflow f). {alpha}-vector is a parameter that characterizes the motion due to air filling (motion as a function of tidal volume v) and {beta}-vector is the parameter that accounts for the motion due to the imbalance of dynamical stress distributions during inspiration and exhalation that causes lung motion hysteresis (motion as a function of airflow f). The parameters {alpha}-vector and {beta}-vector together provide a quantitative characterization of breathing motion that inherently includes the complex hysteresis interplay. The {alpha}-vector and {beta}-vector distributions were examined for each patient to determine overall general patterns and interpatient pattern variations. Results: For 44 patients, the greatest values of |{alpha}-vector| were observed in the inferior and posterior lungs. For the rest of the patients, |{alpha}-vector| reached its maximum in the anterior lung in three patients and the lateral lung in two patients. The hysteresis motion {beta}-vector had greater variability, but for the majority of patients, |{beta}-vector| was largest in the lateral lungs. Conclusions: This is the first report of the three-dimensional breathing motion model parameters for a large cohort of patients. The model has the potential for noninvasively predicting lung motion. The majority of patients exhibited similar |{alpha}-vector| maps and the |{beta}-vector| maps showed greater interpatient variability. The motion parameter interpatient variability will inform our need for custom radiation therapy motion models. The utility of this model depends on the parameter stability over time, which is still under investigation.

Zhao Tianyu; Lu Wei; Yang Deshan; Mutic, Sasa; Noel, Camille E.; Parikh, Parag J.; Bradley, Jeffrey D.; Low, Daniel A. [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)

2009-11-15

207

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

SciTech Connect

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{sup -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 {mu}G). However, the ISM can provide noticeable resistance to the motion of a low-density cloud (n {<=} 0.01 H atoms cm{sup -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.

Kwak, Kyujin; Shelton, Robin L.; Raley, Elizabeth A. [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States)

2009-07-10

208

The Evolution of Gas Clouds Falling in the Magnetized Galactic Halo: High-Velocity Clouds (HVCs) Originated in the Galactic Fountain  

NASA Astrophysics Data System (ADS)

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 ?G). 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.

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

2009-07-01

209

Use of Vestibular Models for Design and Evaluation of Flight Simulator Motion.  

National Technical Information Service (NTIS)

Quantitative models for the dynamics of the human vestibular system are applied to the design and evaluation of flight simulator platform motion. An optimal simulator motion control algorithm is generated to minimize the vector difference between perceive...

S. R. Bussolari L. R. Young A. T. Lee

1988-01-01

210

Earth Exploration Toolbook Chapter: Analyzing Plate Motion Using EarthScope GPS Data  

NSDL National Science Digital Library

DATA: EarthScope GPS Data. TOOLS: Spreadsheet, Google Maps. SUMMARY: Learn how GPS monuments make precise measurements of Earth's surface. Graph motion data and map velocity vectors to explore tectonic motion and surface deformation in the Pacific Northwest.

211

Shocking Changes to Molecular Clouds  

NASA Astrophysics Data System (ADS)

Supersonic motions are commonly observed in molecular clouds as evidenced by larger-than-thermal line widths measured in most species. The shocks that ensue can profoundly effect these clouds, not only dynamically, but chemically. Because shocks compress and heat the gas, chemical reactions that are extremely slow at typical molecular cloud temperatures (T ~ 10-30 K) can proceed rapidly in the wake of a shock. In many cases, compositional changes brought on by a passing shock can endure long after the gas has cooled and returned to its pre-shock state. We have used a coupled time-dependent chemical and dynamical model to investigate the lifetime of such chemical relics in the wake of non-dissociative shocks. Using a Monte Carlo cloud simulation, we explore the effects of stochastic shock activity on molecular gas over a cloud lifetime. Particular attention is paid to the chemistry of H_2O and O_2, two molecules which are predicted to have abundances that are significantly affected by shock-heated gas. Both pure gas-phase and gas-grain chemistry are considered. In agreement with previous studies, we find that shocks with velocities in excess of 10 km s(-1) can chemically process all oxygen not locked in CO into H_2O on timescales of a shock passage time ( ~ \\:few hundred years). For pure gas-phase models, the high water abundance lingers for ~ (4-7) x 10(5) yr, independent of the gas density. A density dependence for the lifetime of H_2O is found in gas-grain models as the water molecules deplete onto grains at the depletion timescale. We demonstrate that the time-averaged abundance of H_2O and O_2 (as well as other tracers, such as SiO and CH_3OH) is a sensitive function of the frequency of shocks. As such, the abundance of H_2O, and to a lesser extent O_2, can be used to trace the shock history in molecular clouds. Equally important, we find that depletion of shock-produced water onto grains can be quite large and is comparable to that observed in molecular clouds. This offers an alternative method to create water-ice mantles without resorting to grain surface chemistry. Observationally, a combination of space-based (for H_2O and O_2) and ground-based (for SiO, CH_3OH, and others) telescopes will be needed to investigate these predictions.

Melnick, Gary J.

1998-05-01

212

Motion Recognition from Video Sequences  

Microsoft Academic Search

This paper proposes a method for recognizing human motions from video sequences, based on the hypothesis that there exists\\u000a a repertoire of movement primitives in biological sensory motor systems. First, a content-based image retrieval algorithm\\u000a is used to obtain statistical feature vectors from individual images. A decimated magnitude spectrum is calculated from the\\u000a Fourier transform of the edge images. Then,

Xiang Yu; Simon X. Yang

2003-01-01

213

Cloud Basics – An Introduction to Cloud Computing  

Microsoft Academic Search

Cloud Computing has attracted a lot of attention in recent times. The media as well as analysts are generally very positive\\u000a about the opportunities Cloud Computing is offering. In May 2008, Merrill Lynch (2008) estimated the cost advantages of Cloud\\u000a Computing to be three to five times for business applications and more than five times for consumer applications. According\\u000a to

Katarina Stanoevska-Slabeva; Thomas Wozniak

214

Determination of magnetic cloud parameters and prediction of magnetic storm intensity  

NASA Astrophysics Data System (ADS)

A program for identifying magnetic clouds in patrol satellite data, which recorded the interplanetary medium parameters near the magnetosphere, has been developed based on the cloud model in the form of a force-free cylindrical flux tube. The program makes it possible to also determine the entire magnetic field distribution in a cloud that approaches the Earth, using the initial satellite measurements. For this purpose, a model cloud (which has the maximal correlation coefficient with an analyzed cloud with respect to three magnetic field vector components and minimal rms deviations of the magnetic field and velocity components) is selected from the preliminarily created database including 2 million model clouds. The obtained magnetic field distribution in a cloud will make it possible to predict the intensity of a magnetic storm that this cloud will cause.

Barkhatov, N. A.; Kalinina, E. A.

2010-08-01

215

Fast Measurement of Vector Miss Distance Based on FFT  

Microsoft Academic Search

To meet the real-time demands of some vector miss distance measurement systems, a fast vector miss distance estimation algorithm is presented in this paper. A small antenna array is used for measuring the movement of a target. Doppler frequency and phase of the signal received by each antenna can be estimated by the proposed fast algorithm. The target motion parameters

Zhiyu Li; Guohua Wei; Siliang Wu

2006-01-01

216

Vectors in Use in a 3D Juggling Game Simulation  

ERIC Educational Resources Information Center

The new representations enabled by the educational computer game the "Juggler" can place vectors in a central role both for controlling and measuring the behaviours of objects in a virtual environment simulating motion in three-dimensional spaces. The mathematical meanings constructed by 13 year-old students in relation to vectors as objects, as a…

Kynigos, Chronis; Latsi, Maria

2006-01-01

217

Local Interstellar Matter: The Apex Cloud  

Microsoft Academic Search

Several nearby individual low column density interstellar cloudlets have been\\u000aidentified based on kinematical features evident in high-resolution CaII\\u000aobservations near the Sun. One of these cloudlets, the ``Aquila-Ophiuchus''\\u000acloud, is within 5 pc of the Sun and located in the solar apex direction. The\\u000avelocity vector of this Apex Cloud is reevaluated and components at this\\u000avelocity are found

Priscilla C. Frisch

2003-01-01

218

Uniform Motion  

NSDL National Science Digital Library

The Video Analysis of Uniform Motion lab uses the Tracker video analysis tool to measure and analyze the motion of a steel ball rolling with constant velocity on an aluminum track. The zip file contains the lab handout, two videos (slower speed ball and faster speed ball), and the Tracker file. To open the Tracker file, download and run Tracker from http://www.cabrillo.edu/~dbrown/tracker/. Tracker is free. The videos can be used with other video analysis software; however, the handout has screen captures from Tracker and instructions specifically written for Tracker.

Titus, Aaron

2010-08-11

219

PSC Meteorology Program Cloud Boutique  

NSDL National Science Digital Library

Plymouth State College (PSC) provides the PSC Meteorology Program Cloud Boutique Website to "provide explanations of and access to detailed pictures of some basic cloud forms." Spectacular images and brief descriptions of high clouds (cirrus, cirrocumulus, and cirrostratus), middle clouds (altocumulus and altostratus), low clouds (cumulus, stratocumulus, stratus, and fog), multi-layer clouds (nimbostratus and cumulonimbus), and orographic clouds (lenticular and cap), among others are included. The site is an excellent general cloud reference.

220

Quantum Motion  

NSDL National Science Digital Library

This resource illustrates the motion of a Gaussian wavepacket in one dimension scattering off of a barrier. The shape and size of the barrier can be changed, including creating a double barrier. The width, initial position, and total energy of the wavefunction can all be changed as well. Dimensionless units are used.

Group, Kansas S.; Zollman, Dean A.

2004-04-04

221

Projectile Motion  

NSDL National Science Digital Library

In this interactive simulation adapted from University of Colorado’s Physics Education Technology project, learn about projectile motion by firing various objects from a virtual cannon into the air. Experiment with the settings and try to hit a target.

Foundation, Wgbh E.

2007-04-19

222

An efficient two-pass MAP-MRF algorithm for motion estimation based on mean field theory  

Microsoft Academic Search

This paper presents a two-pass algorithm for estimating motion vectors from image sequences. In the proposed algorithm, the motion estimation is formulated as a problem of obtaining the maximum a posteriori in the Markov random field (MAP-MRF). An optimization method based on the mean field theory (MFT) is opted to conduct the MAP search. The estimation of motion vectors is

Jie Wei; Ze-Nian Li

1999-01-01

223

Personal Cloud Computing Security Framework  

Microsoft Academic Search

Cloud computing is an evolving term these days. It describes the advance of many existing IT technologies and separates application and information resources from the underlying infrastructure. Personal Cloud is the hybrid deployment model that is combined private cloud and public cloud. By and large, cloud orchestration does not exist today. Current cloud service is provided by web browser or

Sang-Ho Na; Jun-Young Park; Eui-nam Huh

2010-01-01

224

Model Cloud Relationships.  

National Technical Information Service (NTIS)

Contents: Radar Reflectivity Studies; Three-Dimensional Cloud/Mesoscale Model Investigations of Potential Aircraft Icing Regions; Inclusion of Ice Processes in the One-Dimensional Cloud/Turbulence Model.

W. R. Cotton E. E. Hindman G. Tripoli R. L. McAnelly C. Chen

1983-01-01

225

Cloud Computing Strategy.  

National Technical Information Service (NTIS)

The DoD Cloud Computing Strategy has evolved to identify the most effective ways for the Department to capitalize on opportunities and take advantage of cloud computing benefits that accelerate IT delivery, efficiency, and innovation as an Enterprise. Pri...

T. M. Takai

2012-01-01

226

Queue-based block matching algorithm for video compression and motion segmentation  

NASA Astrophysics Data System (ADS)

This paper addresses two issues related to motion estimation using the block matching algorithms (BMA): (1) determining the reliability of the motion vectors of each block, and (2) imposing smoothness constraint to the motion vector field. We introduce a new robust reliability measure to represent the confidence level of the motion vector from the cost function distribution and propose a novel algorithm that incorporates smoothness constraint into the motion vector field evaluation by implementing a priority queue structure based on the reliability measure. In this framework, a smooth motion vector field is evaluated in a single pass without going through iterations typical of many existing optical flow estimation algorithms. Hence it is fast and can easily be incorporated into real-time applications for video compression as well as image segmentation.

Chiew, Tuan-Kiang; Chung-How, James T. H.; Bull, David R.; Canagarajah, C. N.

2004-01-01

227

Star-forming Substructure within Molecular Clouds  

NASA Astrophysics Data System (ADS)

Wide-field far-infrared/submillimeter continuum maps of molecular clouds by the Herschel Space Observatory GBS and HOBYS surveys are revealing the star-forming substructures that lead to star formation in dense gas. In particular, these maps have revealed the central role in clouds of filaments, likely formed through turbulent motions. These filaments appear to be non-isothermal and fragment into cores only when their column densities exceed a stability threshold. Organizations of filament networks suggest the relative role of turbulence and gravity can be traced in different parts of a cloud, and filament intersections may lead to larger amounts of mass flow that form the precursors of high-mass stars or clusters.

Di Francesco, James

2013-03-01

228

Head in the Clouds  

NSDL National Science Digital Library

In this activity, learners create a CloudSpotter wheel and record the different types of clouds they observe twice daily over several days. Use this activity to teach learners how to identify different types of clouds as well as improve their observation skills. If possible, plan this lesson within four days of an upcoming cold front. This will help maximize the variety of clouds the learners will observe. This resource also includes tips about foggy weather safety.

Service, National W.

2013-04-10

229

Computer animation of clouds  

Microsoft Academic Search

Computer animation of outdoor scenes is enhanced by realistic clouds. I discuss several different modelling and rendering schemes for clouds, and show how they evolved in my animation work. These include transparency-textured clouds on a 2D plane, smooth shaded or textured 3D cloud surfaces, and 3D volume rendering. For the volume rendering, I present various illumination schemes, including the density

Nelson Max

1994-01-01

230

Uranus at Equinox: Cloud Morphology and Dynamics  

NASA Astrophysics Data System (ADS)

Near-equinox observations of Uranus by the Keck II telescope and the Hubble Space Telescope on 15 days from 7 June 2007 through 9 September 2007 were used to identify and track cloud features, determine atmospheric motions, characterize cloud morphology and dynamics, and define changes in band structure. Atmospheric motions were obtained by tracking clouds up to 73 N, but we did not find any discrete features between 42 S and 90 S, a lack that has existed since Voyager found a dark UV feature in 1986. For 28 cloud features we obtained extremely high wind speed accuracy through extended tracking times, confirming a small N-S asymmetry in the wind profile. The close agreement with 1986 Voyager observations suggests that the asymmetry may be permanent, although some 2003 observations (Hammel et al., Icarus 175, 534-535, 2005) conflict with this suggestion. In 2007 we found two prominent groups of discrete cloud features with very long lifetimes. The one near 30 S departed from its previous oscillatory motion and in 2005 started a significant northward drift, accompanied by substantial morphological changes. The complex of features near 30 N remained at a nearly fixed latitude, while exhibiting some characteristics of a dark spot accompanied by bright companion features. As noted by Rages et al. (BAAS 39, 425, 2007), a bright band has begun to develop at 45-48 N, while the bright band at 45-48 S has begun to decline, both events in agreement with the idea that the asymmetric band structure of Uranus is a long-delayed (by a large fraction of a season) response to solar forcing. We acknowledge support from the Space Telescope Science Institute, the W. M. Keck Observatory and Foundation, and NASA Planetary Atmospheres and Planetary Astronomy Programs.

Sromovsky, Lawrence A.; Fry, P. M.; Ahue, W. M.; Hammel, H. B.; de Pater, I.; Rages, K. A.; Showalter, M. R.; van Dam, M. A.

2008-09-01

231

Cloud Computing Explained  

ERIC Educational Resources Information Center

|While many talk about the cloud, few actually understand it. Three organizations' definitions come to the forefront when defining the cloud: Gartner, Forrester, and the National Institutes of Standards and Technology (NIST). Although both Gartner and Forrester provide definitions of cloud computing, the NIST definition is concise and uses…

Metz, Rosalyn

2010-01-01

232

Cloud Sustainability Dashboard  

Microsoft Academic Search

Cloud computing is gaining in popularity. At the same time, the global community is becoming increasingly conscious about sustainability. While intuitively Cloud computing, due to resource consolidation and virtualization, economies of large scale, delivery on demand, etc., has the potential to be more sustainable than well tuned data centers, this is not guaranteed. To evaluate and understand Cloud sustainability, we

Martin Arlitt; Sujata Banerjee; Cullen Bash; Yuan Chen; Daniel Gmach; Christopher Hoover; Priya Mahadevan; Dejan Milojicic; Eric Pelletier; R. N. Vishwanath; Amip Shah; Puneet Sharma

2010-01-01

233

Library in the clouds  

Microsoft Academic Search

Purpose – This paper aims to examine the issue of cloud computing and how it relates to digital library service provisioning. Design\\/methodology\\/approach – The paper adopts a viewpoint approach. Findings – The paper is exploratory, and looks at the pros and cons of cloud computing for digital libraries. Practical implications – The subject of cloud computing has been a hot

Robert Fox

2009-01-01

234

Cloud computing security  

Microsoft Academic Search

Cloud computing is a paradigm rapidly being embraced by government and industry as a solution for cost-savings, scalability, and collaboration. While a multitude of applications and services are available commercially for cloud-based solutions, research in this area has yet to fully embrace the full spectrum of potential challenges facing cloud computing. This tutorial aims to provide researchers with a fundamental

Dongwan Shin; William R. Claycomb; Vincent E. Urias

2010-01-01

235

Security in the cloud.  

PubMed

As more provider organizations look to the cloud computing model, they face a host of security-related questions. What are the appropriate applications for the cloud, what is the best cloud model, and what do they need to know to choose the best vendor? Hospital CIOs and security experts weigh in. PMID:21863719

Degaspari, John

2011-08-01

236

Cloud security metrics  

Microsoft Academic Search

Cloud security had not yet distinguished itself as a field separate from information assurance. Its security metrics are currently synonymous with what a security professional would refer to as a third-party or vendor security audit. Where cloud services are viewed in a systems- of-systems context, any comprehensive security validation approach should rely on the ability of a cloud service to

Jennifer Bayuk

2011-01-01

237

Chemical Conversions in Clouds.  

National Technical Information Service (NTIS)

Clouds constitute an extreme atmospheric aerosol in terms of particle size and condensed-phase mass. The large amount of liquid water in clouds as well as the high state of dispersion make clouds a potentially important medium for atmospheric reactions, d...

S. E. Schwartz

1985-01-01

238

Teacher's Domain: Cloud Types  

NSDL National Science Digital Library

This resource describes cloud formation and explains atmospheric processes such as convection, evaporation, and transpiration. The discussion includes how clouds form, some of their properties, and how precipitation is triggered. A multimedia interactive feature explains how clouds are named and identified. Questions for discussion are provided.

2005-01-01

239

Cloud condensation nuclei  

Microsoft Academic Search

The state of knowledge of the particles upon which liquid droplets condense to form atmospheric water clouds is presented. The realization of cloud condensation nuclei (CCN) as a distinct aerosol subset originated with the cloud microphysical measurements and theoretical insights of Patrick Squires 40 years ago. He helped originate and continue the development of CCN counters and made significant CCN

James G. Hudson

1993-01-01

240

On clocks and clouds  

NASA Astrophysics Data System (ADS)

Cumulus clouds exhibit a life cycle that consists of: (a) the growth phase (increasing size, most notably in the vertical direction); (b) the mature phase (growth ceases; any precipitation that develops is strongest during this period); and (c) the dissipation phase (cloud dissipates because of precipitation and/or entrainment; no more dynamical support). Although radar can track clouds over time and give some sense of the age of a cloud, most aircraft in situ measurements lack temporal context. We use large eddy simulations of trade wind cumulus cloud fields from cases during the Barbados Oceanographic and Meteorological Experiment (BOMEX) and Rain In Cumulus over the Ocean (RICO) campaigns to demonstrate a potential cumulus cloud "clock". We find that the volume-averaged total water mixing ratio rt is a useful cloud clock for the 12 clouds studied. A cloud's initial rt is set by the subcloud mixed-layer mean rt and decreases monotonically from the initial value due primarily to entrainment. The clock is insensitive to aerosol loading, environmental sounding and extrinsic cloud properties such as lifetime and volume. In some cases (more commonly for larger clouds), multiple pulses of buoyancy occur, which complicate the cumulus clock by replenishing rt. The clock is most effectively used to classify clouds by life phase.

Witte, M. K.; Chuang, P. Y.; Feingold, G.

2013-09-01

241

Cloud Computing learning  

Microsoft Academic Search

Cloud Computing is evolving as a key technology for sharing resources. Grid Computing, distributed computing, parallel computing and virtualization technologies define the shape of a new era. Traditional distance learning systems lack reusability, portability and interoperability. This paper sees cloud computing ecosystem as a new opportunity in designing cloud computing educational platforms where learning actors can reuse learning resources handled

Panagiotis Kalagiakos; Panagiotis Karampelas

2011-01-01

242

Magnetomechanical Supersonic Waves in Dark Molecular Clouds  

Microsoft Academic Search

We propose and investigate the magnetoelastodynamic mechanism of the wave motions of poorly ionized superparamagnetic gas-dust interstellar medium capable of sustaining long-ranged magnetization. It is suggested that the molecular linewidths inferred from recent Zeeman measurements of the magnetic eld toward the core position in dark interstellar molecular clouds may be due to transverse magnetomechanical waves traveling with supersonic, but sub-Alfvnic,

Jongmann Yang; Sergey Bastrukov

2000-01-01

243

Impact of Microwaves on the Electron Cloud and Incoherent Effects  

SciTech Connect

We consider the use of microwaves for manipulating the electron cloud, describing an exploratory experiment at PEP-II as well as computer simulations of the electron cloud build up in the presence of a microwave for an LHC dipole. We then show that the incoherent effects of the electron cloud--energy loss and transverse emittance growth due to scattering off the electrons--are negligible. This suggests that the disturbance of the coherent electron motion may be another possible application of microwaves, which could prevent beam emittance growth and beam loss.

Decker, Franz-Josef

2002-08-09

244

Projectile Motion  

NSDL National Science Digital Library

Students are introduced to the concept of projectile motion, of which they are often familiar from life experiences,such as playing sports such as basketball or baseball, even though they may not understand the physics involved. Students use tabletop-sized robots to build projectile throwers and measure motion using sensors.They compute distances and velocities using simple kinematic equations and confirm their results through measurements by hand. To apply the concept, students calculate the necessary speed of an object to reach a certain distance in a hypothetical scenaro: A group of hikers stranded at the bottom of a cliff need food, but rescuers cannot deliver it themselves, so they must devise a way to get the food to the hikers.

Applying Mechatronics to Promote Science (AMPS) GK-12 Program,

245

Imaging vector fields using Line Integral Convolution  

SciTech Connect

Imaging vector fields has applications in science, art, image processing and special effects. An effective new approach is to use linear and curvilinear filtering techniques to locally blur textures along a vector field. This approach builds on several previous texture generation and filtering techniques. It is, however, unique because it is local, one-dimensional and independent of any predefined geometry or texture. The technique is general and capable of imaging arbitrary two- and three-dimensional vector fields. The local one-dimensional nature of the algorithm lends itself to highly parallel and efficient implementations. Furthermore, the curvilinear filter is capable of rendering detail on very intricate vector fields. Combining this technique with other rendering and image processing techniques -- like periodic motion filtering -- results in richly informative and striking images. The technique can also produce novel special effects.

Cabral, B.; Leedom, L.C.

1993-03-01

246

Vectorization of Monte Carlo particle transport  

SciTech Connect

Fully vectorized versions of the Los Alamos National Laboratory benchmark code Gamteb, a Monte Carlo photon transport algorithm, were developed for the Cyber 205/ETA-10 and Cray X-MP/Y-MP architectures. Single-processor performance measurements of the vector and scalar implementations were modeled in a modified Amdahl's Law that accounts for additional data motion in the vector code. The performance and implementation strategy of the vector codes are related to architectural features of each machine. Speedups between fifteen and eighteen for Cyber 205/ETA-10 architectures, and about nine for CRAY X-MP/Y-MP architectures are observed. The best single processor execution time for the problem was 0.33 seconds on the ETA-10G, and 0.42 seconds on the CRAY Y-MP. 32 refs., 12 figs., 1 tab.

Burns, P.J.; Christon, M.; Schweitzer, R.; Lubeck, O.M.; Wasserman, H.J.; Simmons, M.L.; Pryor, D.V. (Colorado State Univ., Fort Collins, CO (USA). Computer Center; Los Alamos National Lab., NM (USA); Supercomputing Research Center, Bowie, MD (USA))

1989-01-01

247

Motion Pictures  

Microsoft Academic Search

George Rehrauer, THE MACMILLAN BIBLIOGRAPHY: A CRITICAL GUIDE TO THE LITERATURE OF THE MOTION PICTURE (New York: Macmillan, 1982 2 vol. —the first volume is the bibliography itself, $90.00; the second is the index, $50.00).Paula Rohrlick, EXPLORING THE ARTS: FILM AND VIDEO PROGRAMS FOR YOUNG VIEWERS (New York: R. R. Bowker, 1982—$24.95, paper, plus shipping and handling).Jason E. Squire, THE

George Rehrauer; Paula Rohrlick; Jason E. Squire; Gregory Goodell; James Curtis; William Schelly; Bruce Cook; Marsha McCreadle; William Luhr; Allen L. Woll; Norma Kagan; David Wilson; Nicholas Pronay; D. W. Spring; Ina Bertrand; Diane Collins; John Tulloch; Roy Armes; Bruce F. Kawin; Peter Rollins; Susan Myrick; Frank Beaver

1983-01-01

248

Kepler Motion  

NSDL National Science Digital Library

This java applet displays Kepler's three laws of planetary motion in action. Users can select which of the three laws they wish to be animated and alter the initial conditions, observing how orbital paths and velocities change. Kepler derived his three laws after years of study on data that he inherited from his mentor, Tycho Brahe. Instructions on how to use the animation are provided, and a list of links to other related sites is included.

Hwang, Fu-Kwun

2004-10-27

249

Seasonal Cloud Cover Variations  

NSDL National Science Digital Library

This lesson is designed to help students gain knowledge in using the MY NASA DATA Live Access Server (LAS) to specify and download a microset of data, then to use the data to determine the seasonal cloud coverage and the occurrence of different cloud types, by percent, in the North Carolina (or their local area). Students will identify different cloud types and determine their seasonality. They will graph the data and explore whether there is a correlation between season, cloud cover and type of cloud most prevalent during each season. The lesson provides detailed procedure, related links and sample graphs, follow-up questions and extensions, and Teacher Notes.

2010-03-14

250

Introduction to Clouds  

NSDL National Science Digital Library

This site provides the user an opportunity to explore storm clouds and climate change through the use of NASA climate research data obtained through satellite imaging. The user is challenged to investigate actual scientific research data on clouds and storms, and make observations and interpretations available to NASA research scientists for review. Topics addressed by these investigations include the role of clouds in relation to the changing climate of Earth, the role of clouds in warming or cooling the planet, and the major types of clouds produced by storms.

Tselioudis, George; Petersen, Christopher

1997-01-01

251

THE WATER CYCLE/ CLOUDS  

NSDL National Science Digital Library

Students will learn about the water cycle and how it works. You will explore many resources to find out many new factors about the water cycle. What is the water cycle? National water cycle Name the 4 water parts of the water cycle? Weather wonders Where are 3 places that the water cycle exists- What happens after condensation? animated water cycle Name 4 types of clouds? What is the highest level cloud called? Which cloud is associated with powerful thunderstorms? Cloud Types What do clouds have to do with the water cycle? National water cycle What is ...

Ms.brown

2009-04-06

252

MotionExplorer: Exploratory Search in Human Motion Capture Data Based on Hierarchical Aggregation.  

PubMed

We present MotionExplorer, an exploratory search and analysis system for sequences of human motion in large motion capture data collections. This special type of multivariate time series data is relevant in many research fields including medicine, sports and animation. Key tasks in working with motion data include analysis of motion states and transitions, and synthesis of motion vectors by interpolation and combination. In the practice of research and application of human motion data, challenges exist in providing visual summaries and drill-down functionality for handling large motion data collections. We find that this domain can benefit from appropriate visual retrieval and analysis support to handle these tasks in presence of large motion data. To address this need, we developed MotionExplorer together with domain experts as an exploratory search system based on interactive aggregation and visualization of motion states as a basis for data navigation, exploration, and search. Based on an overview-first type visualization, users are able to search for interesting sub-sequences of motion based on a query-by-example metaphor, and explore search results by details on demand. We developed MotionExplorer in close collaboration with the targeted users who are researchers working on human motion synthesis and analysis, including a summative field study. Additionally, we conducted a laboratory design study to substantially improve MotionExplorer towards an intuitive, usable and robust design. MotionExplorer enables the search in human motion capture data with only a few mouse clicks. The researchers unanimously confirm that the system can efficiently support their work. PMID:24051792

Bernard, Jürgen; Wilhelm, Nils; Krüger, Björn; May, Thorsten; Schreck, Tobias; Kohlhammer, Jörn

2013-12-01

253

Cloud processing, cloud evaporation and Angström exponent  

NASA Astrophysics Data System (ADS)

With a cloud parcel model we investigate how cloud processing and cloud evaporation modify the size distribution and the Angström exponent of an aerosol population. Our study provides a new explanation for the observed variability of the aerosol optical thickness and Angström exponent in the vicinity of clouds. Cloud processing causes a decrease of aerosol particle concentrations, relatively most efficiently in the coarse mode, and reduces the relative dispersion of the aerosol distribution. As a result the Angström exponent of the aerosol increases. The Angström exponent is very sensitive for changes in relative humidity during cloud evaporation, especially between 90% and 100%. In addition, kinetic limitations delay evaporation of relatively large cloud drops, especially in clean and mildly polluted environments where the coarse mode fraction is relatively large. This hampers a direct relation between the aerosol optical thickness, the Angström exponent and the ambient relative humidity, which may severely complicate interpretation of these parameters in terms of aerosol properties, such as the fine mode fraction.

Roelofs, G.-J.; Kamphuis, V.

2009-01-01

254

The dependence of clouds and their radiative impacts on the large-scale vertical velocity  

Microsoft Academic Search

Middle-tropospheric vertical velocity(o500) is used to isolate the effect of large-scale dynamics on the observed radiation budget and cloud properties in the Tropics. The ratio of shortwave to longwave cloud forcing (N=-SWCF\\/LWCF) is approximately 1.2 and independent of the magnitude of w5oo when it is upward over the warmer water. Increasingly negative net cloud forcing (NetCRF) with increasing upward motion

Jian Yuan

2007-01-01

255

Homogeneous ice nucleation and supercooled liquid water in orographic wave clouds  

Microsoft Academic Search

This study investigates ice nucleation mechanisms in cold lenticular wave clouds, a cloud type characterized by quasi-steady-state air motions and microphysical properties. It is concluded that homogeneous ice nucleation is responsible for the ice production in these clouds at temperatures below about -33[degrees]C. The lack of ice nucleation observed above -33[degrees]C indicates a dearth of ice-forming nuclei, and hence heterogeneous

Andrew J. Heymsfield; Larry M. Miloshevich

1993-01-01

256

Tropospheric clouds in Antarctica  

NASA Astrophysics Data System (ADS)

Compared to other regions, little is known about clouds in Antarctica. This arises in part from the challenging deployment of instrumentation in this remote and harsh environment and from the limitations of traditional satellite passive remote sensing over the polar regions. Yet clouds have a critical influence on the ice sheet's radiation budget and its surface mass balance. The extremely low temperatures, absolute humidity levels, and aerosol concentrations found in Antarctica create unique conditions for cloud formation that greatly differ from those encountered in other regions, including the Arctic. During the first decade of the 21st century, new results from field studies, the advent of cloud observations from spaceborne active sensors, and improvements in cloud parameterizations in numerical models have contributed to significant advances in our understanding of Antarctic clouds. This review covers four main topics: (1) observational methods and instruments, (2) the seasonal and interannual variability of cloud amounts, (3) the microphysical properties of clouds and aerosols, and (4) cloud representation in global and regional numerical models. Aside from a synthesis of the existing literature, novel insights are also presented. A new climatology of clouds over Antarctica and the Southern Ocean is derived from combined measurements of the CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellites. This climatology is used to assess the forecast cloud amounts in 20th century global climate model simulations. While cloud monitoring over Antarctica from space has proved essential to the recent advances, the review concludes by emphasizing the need for additional in situ measurements.

Bromwich, David H.; Nicolas, Julien P.; Hines, Keith M.; Kay, Jennifer E.; Key, Erica L.; Lazzara, Matthew A.; Lubin, Dan; McFarquhar, Greg M.; Gorodetskaya, Irina V.; Grosvenor, Daniel P.; Lachlan-Cope, Thomas; van Lipzig, Nicole P. M.

2012-01-01

257

A Dynamic Analysis of the Upper Extremity: Planar Motions1  

Microsoft Academic Search

Free body diagrams of arm segments show what forces are involved in planar motions. To represent equilibrium D'Alembert's principle is applied in graphical vector diagrams. From these diagrams are derived equations for determining joint force and torque reactions to weight and inertia. The equations make it clear that accelerations and physical constants are needed. A graphical vector acceleration diagram shows

J. Raymond Pearson; Dale R. McGinley; Leo M. Butzel

1963-01-01

258

Improving optical bench radius measurements using stage error motion data  

Microsoft Academic Search

We describe the application of a vector-based radius approach to optical bench radius measurements in the presence of imperfect stage motions. In this approach, the radius is defined using a vector equation and homogeneous transformation matrix formulism. This is in contrast to the typical technique, where the displacement between the confocal and cat's eye null positions alone is used to

Tony L. Schmitz; Neil Gardner; Matthew Vaughn; Kate Medicus; Angela Davies

2008-01-01

259

Numerical study of coupled-bunch instability caused by an electron cloud  

Microsoft Academic Search

An electron cloud induces a wake force on a charged particle beam which creates correlations between bunches---i.e., a small displacement of a bunch creates a perturbation of the electron cloud, which affects the motions of the following bunches, with the result that a coupled-bunch instability is caused. The coupling mode of the instability is determined by the motion of the

S. S. Win; K. Ohmi; H. Fukuma; M. Tobiyama; J. Flanagan; S. Kurokawa

2005-01-01

260

Are the Magellanic Clouds on Their First Passage about the Milky Way?  

Microsoft Academic Search

Recent proper-motion measurements of the Large and Small Magellanic Clouds (LMC and SMC, respectively) by Kallivayalil and coworkers suggest that the 3D velocities of the Clouds are substantially higher (~100 km s-1) than previously estimated and now approach the escape velocity of the Milky Way (MW). Previous studies have also assumed that the Milky Way can be adequately modeled as

Gurtina Besla; Nitya Kallivayalil; Lars Hernquist; Brant Robertson; T. J. Cox; Roeland P. van der Marel; Charles Alcock

2007-01-01

261

An Interaction of a Magellanic Leading Arm High-Velocity Cloud with the Milky Way Disk  

Microsoft Academic Search

The Leading Arm of the Magellanic system is a tidally formed H I feature extending ~60° from the Magellanic Clouds ahead of their direction of motion. Using atomic hydrogen (H I) data from the Galactic All-Sky Survey (GASS), supplemented with data from the Australia Telescope Compact Array, we have found evidence for an interaction between a cloud in the Leading

N. M. McClure-Griffiths; L. Staveley-Smith; Felix J. Lockman; M. R. Calabretta; H. Alyson Ford; P. M. W. Kalberla; T. Murphy; H. Nakanishi; D. J. Pisano

2008-01-01

262

Efficient Cost Measures for Motion Compensation at Low Bit Rates (Extended Abstract)  

Microsoft Academic Search

We make a case that, even with severe efficiency constraints, taking thenumber of bits to code each motion vector into account when estimating motionfor video compression results in significantly better performance at low bitrates, using simulation studies on established benchmark image sequences. Inparticular, we examine an algorithm that differs from a "vanilla" implementationof the H.261 standard by choosing motion vectors

Dzung T. Hoang; Philip M. Long; Jeffrey Scott Vitter

1996-01-01

263

The research on DMSP nighttime cloud image segmentation  

Microsoft Academic Search

In this paper we employ the Integrated Active Contour (IAC) model of vector-value image segmentation and C-V model based on PDE in the segmentation of two channels DMSP nighttime satellite cloud images. The results of segmentation show that the IAC model can integrate the information of each channel throughout the segmentation and can be employed in the image with uneven

Kai Liu; Zheng Kou

2011-01-01

264

Solar angles revisited using a general vector approach  

SciTech Connect

Rather than follow the standard technique using direction cosines or major axes vectors to define the angles of the sun, we develop the necessary formulae from a 3-tuple vector based analysis. The direction of the sun with respect to a Cartesian coordinate system is defined as a unit vector, as is the orthogonal to a surface intended to accept solar radiation. The vector formulation is powerful and universal. More importantly, the diagrams used to describe the relative motion of the sun with respect to the Earth are quite simple, leading to less confusion when translating the geometry to algebra. An interesting result on the change in solar angle with time follows. (author)

Parkin, Robert E. [Department of Mechanical Engineering, University of Massachusetts, 1 University Avenue, Lowell, MA 01854 (United States)

2010-06-15

265

Classifying Human Motion in Virtual Environments  

Microsoft Academic Search

This paper presents a technique for classifying human motion through a virtual environment using Support Vector Machines and Kernel learning. We demonstrate that use of a virtual world significantly eases data collection and processing. Our technique can handle high dimensional data and requires little domain knowledge to implement. Previous techniques require domain knowledge and do not trans- late well from

Chris White

266

Bulldozing Your Way Through Projectile Motion.  

ERIC Educational Resources Information Center

Presents two models and two demonstrations targeted at student understanding of projectile motion as the sum of two independent, perpendicular vectors. Describes materials required, construction, and procedures used. Includes a discussion of teaching points appropriate to each demonstration or model. (JM)

Lamb, William G.

1983-01-01

267

Rotating Motion  

NSDL National Science Digital Library

In these problems, two people ride on a merry-go-round (radius fixed at 10 m..it's big!). One rider tosses a ball toward the other. The period of motion can be varied as can the initial velocity of the ball, relative to rider. One of the problems is to select the initial velocity of the ball so that it passes through center of the merry-go-round. Another is for the rider who throws the ball to catch it him/herself after exactly half a rotation.

Christian, Wolfgang; Belloni, Mario

2008-02-19

268

Force & Motion Microworld  

Microsoft Academic Search

This program is intended to help students develop a conceptual qualitative understanding of the relations between force and motion and to confront their alternative conceptions in this domain. Force & Motion Microworld consists of four topics: Motion Graphs: understanding of velocity - time graphs Spaceship: linear frictionless horizontal motion Model Car: linear horizontal motion with friction Skydiver: vertical (downward) motion

Miky Ronen

1999-01-01

269

Recursive Estimation of Motion, Structure, and Focal Length  

Microsoft Academic Search

We present a formulation for recursive recoveryof motion, pointwise structure, and focal length from featurecorrespondences tracked through an image sequence.In addition to adding focal length to the state vector, severalrepresentational improvements are made over earlierstructure from motion formulations, yielding a stable andaccurate estimation framework which applies uniformly toboth true perspective and orthographic projection. Resultson synthetic and real imagery illustrate the...

Ali Azarbayejani; Alex P. Pentland

1995-01-01

270

A positive recurrent reflecting Brownian motion with divergent fluid path  

Microsoft Academic Search

Semimartingale reflecting Brownian motions (SRBMs) are diffusion processes with state space the d-dimensional nonnegative orthant, in the interior of which the processes evolve according to a Brownian motion, and that reflect against the boundary in a specified manner. The data for such a process are a drift vector ?, a nonsingular d×d covariance matrix ?, and a d×d reflection matrix

Maury Bramson

2011-01-01

271

A Positive Recurrent Reflecting Brownian Motion with Divergent Fluid Path  

Microsoft Academic Search

Semimartingale reflecting Brownian motions (SRBMs) are diffusion processes with state space the d-dimensional nonnegative orthant, in the interior of which the processes evolve according to a Brownian motion, and that reflect against the boundary in a specified manner. The data for such a process are a drift vector {\\\\theta}, a nonsingular d \\\\times d covariance matrix {\\\\Sigma}, and a d

Maury Bramson

2010-01-01

272

THE CALIFORNIA MOLECULAR CLOUD  

SciTech Connect

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 {approx} 10{sup 5} M{sub 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{sub 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{sub 2}) {approx} a few x 10{sup 4} cm{sup -3}.

Lada, Charles J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lombardi, Marco [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748, Garching (Germany); Alves, Joao F., E-mail: clada@cfa.harvard.ed, E-mail: mlombard@eso.or, E-mail: jalves@caha.e [Calar Alto Observatory, C/Jesus Durban Remon, 2-2, 04004 Almeria (Spain)

2009-09-20

273

Cloud processing of nitrate  

NASA Astrophysics Data System (ADS)

The role of clouds in the transport and transformation of tropospheric pollutants was investigated through airborne measurements made out of Cleveland, Ohio, from 21 July to 18 August 2004, as part of the International Consortium for Atmospheric Research on Transport and Transformation 2004 program. Observations of gas-phase nitrate, size-resolved particulate nitrate, cloud water nitrate, and size-distributed cloud residual nitrate are used to examine changes in the partitioning of nitrate from precloud to postcloud as a function of particle size. The [NO3-]/[SO42-] ratio was highest in the bulk cloud water and higher in the cloud droplet residuals compared with the below-cloud aerosols. Most of the nitrate entered the cloud water as HNO3, and in 30% of 43 size distributions examined, the nitrate in the cloud droplets was found in residual particle sizes smaller than those of sulfate. Simulations from a trace gas-aerosol-cloud parcel model show that this size difference results from differences in the processes by which nitrate and sulfate enter cloud water. The transfer of HNO3 to cloud droplets is governed primarily by gas-phase mass transfer to the droplets, leading to greater accumulation in the smaller, more numerous droplets with higher total surface area. In contrast, much of the sulfate in the cloud water is the result of nucleation scavenging, which distributes the sulfate mass toward slightly larger sizes. The extent of separation between nitrate and sulfate is dependent on the cloud base sulfate size distribution and the factors that govern both HNO3 and SO2 uptake, with subsequent S(IV) oxidation.

Hayden, K. L.; MacDonald, A. M.; Gong, W.; Toom-Sauntry, D.; Anlauf, K. G.; Leithead, A.; Li, S.-M.; Leaitch, W. R.; Noone, K.

2008-09-01

274

Vector-valued wavelets and vector filter banks  

Microsoft Academic Search

In this paper, we introduce vector-valued multiresolution analysis and vector-valued wavelets for vector-valued signal spaces. We construct vector-valued wavelets by using paraunitary vector filter bank theory. In particular, we construct vector-valued Meyer wavelets that are band-limited. We classify and construct vector-valued wavelets with sampling property. As an application of vector-valued wavelets, multiwavelets can be constructed from vector-valued wavelets. We show

Xiang-Gen Xia; B. W. Suter

1996-01-01

275

Microphysical properties of ice clouds from polarization calculations  

NASA Astrophysics Data System (ADS)

Uncertainties associated with the radiative properties of ice clouds remain an active research area because of the importance these clouds have in atmospheric radiative transfer problems and the energy balance of the Earth. The polarization state of radiation scattered from ice clouds can provide clues to their microphysical properties and provide a better understanding of their radiative properties. In this study we investigate the effective Mueller matrix of ice clouds composed of different ice particle habits and size distributions. Both smooth and roughened particles are considered, including those assumed for the current operational MODIS collection 5 ice cloud products and a new habit mixture under consideration for the upcoming collection 6 products. The full Stokes vector is simulated using a rigorous vector radiative transfer model developed by de Haan et al. (1987). The effective Mueller matrix is then derived to study the sensitivity of this matrix to the assumed microphysical properties of ice clouds, and simulated results are compared with observations from the POLDER (POLarization and Directionality of the Earth’s Reflectances) instrument.

Cole, B. H.; Yang, P.; Riedi, J.; Baum, B. A.

2010-12-01

276

Vector Addition Patterns Model  

NSDL National Science Digital Library

The Vector Addition Patterns model illustrates the tail-to-tip method of adding vectors. The table at the bottom shows the components and lengths of the vectors. You can also rotate the vectors and trace out some interesting patterns. The Vector Addition Patterns model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition_patterns.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-02

277

Dual Motion Valve with Single Motion Input.  

National Technical Information Service (NTIS)

A dual motion valve (A) includes two dual motion valve assemblies with a rotary input which allows the benefits of applying both rotary and axial motion to a rotary sealing element with a plurality of ports. The motion of the rotary sealing element during...

R. R. Belew

1985-01-01

278

Using Motion Graph for Interactive Motion Edit  

Microsoft Academic Search

Motion Graph, as an effective data structure for captured data, can be adopted to improve the automatism in motion edit, preserving the details of motion. But the traditional method based on Motion Graph always takes lot of time in constructing and searching, especially searching time which makes it not suitable for interactive editing. This paper introduces a novel method about

Le Zheng; Zhigeng Pan; Bing Tang

279

Taxonomy of cloud computing services  

Microsoft Academic Search

Cloud computing is a highly discussed topic, and many big players of the software industry are entering the development of cloud services. Several companies want to explore the possibilities and benefits of cloud computing, but with the amount of cloud computing services increasing quickly, the need for a taxonomy framework rises. This paper describes the available cloud computing services, and

C. N. Hoefer; G. Karagiannis

2010-01-01

280

Spacebased estimation of moisture transport in marine atmosphere using support vector regression  

Microsoft Academic Search

An improved algorithm is developed based on support vector regression (SVR) to estimate horizonal water vapor transport integrated through the depth of the atmosphere (?) over the global ocean from observations of surface wind-stress vector by QuikSCAT, cloud drift wind vector derived from the Multi-angle Imaging SpectroRadiometer (MISR) and geostationary satellites, and precipitable water from the Special Sensor Microwave\\/Imager (SSM\\/I).

Xiaosu Xie; W. Timothy Liu; Benyang Tang

2008-01-01

281

On the Likelihood of Electrical Activity in Titan's Tropospheric Clouds  

NASA Astrophysics Data System (ADS)

An opportunity to search for lightning in Titan occurred during the Voyager 1 encounter with Saturn. Optically thick cloud and haze layers in the stratosphere prevented lightning detection at optical wavelengths. A search for lightning-radiated signals at radio wavelengths yielded negative results. The lack of terrestrial-like lightning does not dismiss, however, the possibility of other types of unusual lightning discharges in Titan. Titan's atmosphere appears to contain no polarizable gas that could lead to generation of a gross electrical structure of clouds by precipitation mechanisms. Instead the electrical dipole within Titan's clouds could result by convective motions to bring externally derived ions into the cloud, where they are attached to cloud particles. These ions and precipitating particles are continuously being generated by cosmic ray and Saturnian magnetospheric interactions with Titan's atmosphere. The net dipole within the cloud would result from updrafts transporting the positively charged particles to its upper portions while the downdrafts deliver negative charged aerosols from above the cloud top to the base. It is expected that weak electric fields would be developed within Titan's clouds that would result in corona discharge and weak intracloud lightning activity.

Navarro-Gonzalez, R.

1997-07-01

282

Respiratory lung motion analysis using a nonlinear motion correction technique for respiratory-gated lung perfusion SPECT images  

Microsoft Academic Search

Objective  This study evaluated the respiratory motion of lungs using a nonlinear motion correction technique for respiratory-gated single\\u000a photon emission computed tomography (SPECT) images.\\u000a \\u000a \\u000a \\u000a Methods  The motion correction technique corrects the respiratory motion of the lungs nonlinearly between two-phase images obtained\\u000a by respiratory-gated SPECT. The displacement vectors resulting from respiration can be computed at every location of the lungs.\\u000a Respiratory lung motion

Hidenori Ue; Hideaki Haneishi; Hideyuki Iwanaga; Kazuyoshi Suga

2007-01-01

283

Motion analysis of structures (MAS) for flexible multibody systems: planar motion of solids  

Microsoft Academic Search

In this paper, an approach named Motion Analysis of Structures (MAS) is introduced to analyze planar motion of solids. The\\u000a theoretical basis of MAS is constructed on vector mechanics instead of analytical mechanics. Four procedures are involved\\u000a to embody this approach. Namely, (a) discretization of structure, (b) discretization of particle path, (c) evaluation of deformations\\u000a and internal forces, and (d) time integration. The first

Tung-Yueh Wu; Jyh-Jone Lee; Edward C. Ting

2008-01-01

284

An improved motion-compensated restoration method for damaged color motion picture films  

Microsoft Academic Search

In this paper, we propose an improved motion-compensated restoration method for color motion picture films deteriorated due to flashing blotches. The method consists of an improved multiresolution block matching with log-D search, a rank ordered differences-based blotch detection and 3D vector median filtering for interpolation of missing data, and utilizes five consecutive frames. Performance of the method is tested on

Ali Gangal; Temel Kayikçioglu; Bekir Dizdaroglu

2004-01-01

285

Introduction to Clouds  

NSDL National Science Digital Library

This site gives students an opportunity to explore storm clouds and climate change through the use of National Aeronautic and Space Administration (NASA) climate research data obtained through satellite imaging. The challenge is to investigate actual scientific research data on clouds and storms, and make the resulting observations and interpretations available to NASA research scientists for review. The interactive site will allow students to discover what the major types of clouds produced by storms are and whether these clouds help to cool or warm the Earth's surface. Storms are the major producers of clouds in the Earth's atmosphere, so students investigate the relationship between the types of clouds in order to make their conclusions.

286

Energy Aware Clouds  

NASA Astrophysics Data System (ADS)

Cloud infrastructures are increasingly becoming essential components for providing Internet services. By benefiting from economies of scale, Clouds can efficiently manage and offer a virtually unlimited number of resources and can minimize the costs incurred by organizations when providing Internet services. However, as Cloud providers often rely on large data centres to sustain their business and offer the resources that users need, the energy consumed by Cloud infrastructures has become a key environmental and economical concern. This chapter presents an overview of techniques that can improve the energy efficiency of Cloud infrastructures. We propose a framework termed as Green Open Cloud, which uses energy efficient solutions for virtualized environments; the framework is validated on a reference scenario.

Orgerie, Anne-Cécile; de Assunção, Marcos Dias; Lefèvre, Laurent

287

Long-term memory motion-compensated prediction  

Microsoft Academic Search

Long-term memory motion-compensated prediction extends the spatial displacement vector utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensated prediction. The long-term memory covers several seconds of decoded frames at the encoder and decoder. The use of multiple frames for motion compensation in most cases

Thomas Wiegand; Xiaozheng Zhang; Bernd Girod

1999-01-01

288

An efficient parallel motion estimation algorithm for digital image processing  

Microsoft Academic Search

The authors present an efficient block-matching algorithm called the parallel hierarchical one-dimensional search (PHODS) for motion estimation. Instead of finding the two-dimensional motion vector directly, the PHODS finds two one-dimensional displacements in parallel on the two axes (say x and y) independently within the search area. The major feature of this algorithm is that its search speed for the motion

Liang-Gee Chen; Wai-Ting Chen; Yeu-Shen Jehng; Tzi-Dar Chiuch

1991-01-01

289

Animation of orthogonal texture patterns for vector field visualization.  

PubMed

This paper introduces orthogonal vector field visualization on 2D manifolds: a representation by lines that are perpendicular to the input vector field. Line patterns are generated by line integral convolution (LIC). This visualization is combined with animation based on motion along the vector field. This decoupling of the line direction from the direction of animation allows us to choose the spatial frequencies along the direction of motion independently from the length scales along the LIC line patterns. Vision research indicates that local motion detectors are tuned to certain spatial frequencies of textures, and the above decoupling enables us to generate spatial frequencies optimized for motion perception. Furthermore, we introduce a combined visualization that employs orthogonal LIC patterns together with conventional, tangential streamline LIC patterns in order to benefit from the advantages of these two visualization approaches. In addition, a filtering process is described to achieve a consistent and temporally coherent animation of orthogonal vector field visualization. Different filter kernels and filter methods are compared and discussed in terms of visualization quality and speed. We present respective visualization algorithms for 2D planar vector fields and tangential vector fields on curved surfaces, and demonstrate that those algorithms lend themselves to efficient and interactive GPU implementations. PMID:18467751

Bachthaler, Sven; Weiskopf, Daniel

290

Cloud Infrastructure Security  

Microsoft Academic Search

\\u000a Cloud computing can help companies accomplish more by eliminating the physical bonds between an IT infrastructure and its\\u000a users. Users can purchase services from a cloud environment that could allow them to save money and focus on their core business.\\u000a At the same time certain concerns have emerged as potential barriers to rapid adoption of cloud services such as security,

Dimiter Velev; Plamena Zlateva

2010-01-01

291

Magellanic Clouds: Interstellar Phenomena  

NASA Astrophysics Data System (ADS)

The LARGE and SMALL MAGELLANIC CLOUDS are two naked-eye IRREGULAR GALAXIES in the southern sky. Extending over ˜7°×7°, the Large Magellanic Cloud has a prominent stellar bar superposed on a disk, which is tilted by about 40° with respect to the sky. The Small Magellanic Cloud, ˜4°×3°, has a bar-like structure, with its long axis stretched along the line of sight. The Large and Small Magellanic ...

Chu, Y.; Murdin, P.

2000-11-01

292

Energy Aware Clouds  

Microsoft Academic Search

\\u000a Cloud infrastructures are increasingly becoming essential components for providing Internet services. By benefiting from economies\\u000a of scale, Clouds can efficiently manage and offer a virtually unlimited number of resources and can minimize the costs incurred\\u000a by organizations when providing Internet services. However, as Cloud providers often rely on large data centres to sustain\\u000a their business and offer the resources that

Anne-Cécile Orgerie; Marcos Dias de Assunção; Laurent Lefèvre

2011-01-01

293

A modified algorithm for generation of 3D GVF field from point cloud  

NASA Astrophysics Data System (ADS)

This paper presents an algorithm for generation of a force field from point cloud in three-dimensional space. The force field is calculated based on the approach of gradient vector flow (GVF). Therefore, the force field is named as 3D GVF field. By converting the point cloud into a 3D edge image, the algorithm diffuses the gradient of 3D edge image along the gradient direction of 3D edge image. The generated 3D GVF field of point cloud can be further used for point cloud processing such as segmentation, reparation or recognition.

Liu, Shoubin; Niu, Wenguang

2012-01-01

294

Vector Components Model  

NSDL National Science Digital Library

The Vector Components model allows the user to split a vector into its components, and practice finding the magnitude and direction of a vector if you know the components. In the "Find components" mode, you are given the magnitude and direction of the vector, and your goal is to find the x-component and the y-component of the vector. In the "Find magnitude and direction" mode, you are given the two components, and you need to find the magnitude and direction of the vector. The Vector Components was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_components.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-27

295

Microbiologists search the clouds  

NASA Astrophysics Data System (ADS)

On 22 May, a team of microbiologists used a prototype cloud-catcher mounted on a research plane to collect samples from low-lying cumulus clouds near Oxford, England. The researchers, from the University of East London (UEL), are investigating whether an active and self-sustaining ecosystem exists in clouds, and whether airborne microbes may play an active role in forming clouds and causing rainfall.While scientists have known that microorganisms, including bacteria, fungal spores, and algae, can survive and possibly reproduce in the atmosphere, the challenge, according to the UEL researchers, is to accurately detect, identify, and analyze microbial communities.

Showstack, Randy

296

Turbulence in atmospheric clouds  

NASA Astrophysics Data System (ADS)

Atmospheric clouds, a crucial piece of the climate change problem, are almost iconic as visualizations of turbulence. Some of the many aspects of turbulence interacting with cloud particles and radiation fields will be reviewed: from inhomogeneous mixing, to inertial clustering, to stochastic coalescence. The fundamental role of the Lagrangian viewpoint in the cloud-particle coalescence problem will be discussed in the context of a toy model of stochastic rain formation. This provides a context for discussing the emerging recognition of the dominant role of fluctuations in cloud processes.

Shaw, Raymond

2007-11-01

297

Plate Motions  

NSDL National Science Digital Library

To prepare for this exercise students read the Chapter on plate tectonics in their text book. In class, they are given a color isochron map of the sea floor. They are given 4 tasks: Answer basic questions about the timing and rate of opening of the N. and S. Atlantic; Determine what has happened to the oceanic crust that is created on the eastern side of the East Pacific Rise; Determine what type of plate boundary existed on the western edge of the N. America plate before the San Andreas Fault and when this transition occurred; and Reconstruct the motion of the plates over the last 40 Ma assuming that the surface area of the Earth has not changed.

Nunn, Jeffrey

298

Olympic Motion  

NSDL National Science Digital Library

The following resource is fromLessonopoly, which has created student activities and lesson plans to support the video series, Science of the Olympic Winter Games, created by NBC Learn and the National Science Foundation. Featuring exclusive footage from NBC Sports and contributions from Olympic athletes and NSF scientists, the series will help teach your students valuable scientific concepts. In this particular lesson, students will learn about motion and their body at two different levels: cellular and muscular. Students will examine human blood to identify its basic components and will conduct a test to determine their reflex reaction time. Students will also create a flow chart to show the role of cells in muscle contraction.

2010-01-01

299

Ice particle collision electrification in mixed phase cloud.  

NASA Astrophysics Data System (ADS)

Over the last 50 years, laboratory experiments have demonstrated the dependence and complexity of ice particle electrification following particle impact and bounce from actively riming simulated graupel particles. Results showed dependence on temperature, liquid water content, particle size, and impact velocity as well as the effect of trace impurity. In these experiments, the relative concentration of ice and water has been provided in different ways for simulating the growth environment, leading to questions about the most appropriate situation in the atmosphere to apply the results. In early experiments, particle growth was simulated in ice and supercooled cloud, well mixed mechanically. In more recent experiments, the environment has been provided by forming the ice and water cloud separately until quasi-equilibrium is reached and bringing the clouds together to be mixed a few seconds prior to impact on the growth particle. This may be accomplished in turbulent or laminar flow depending on the system size and velocity chosen. Thus results are to be compared with differing scales of bringing together of ice and supercooled cloud flows in the atmosphere (as in a convective or a stratiform system) and the decay of large cloud scale motions having ice or water mixed on a variety of scales as the cloud size turbulent motions decay to smaller turbulent and ultimately laminar eddies. These considerations predicate the utility of experiments already carried out and suggest new experiments under different conditions to seek results which up to now have been elusive.

Saunders, C.; Hallett, J.

2005-12-01

300

Rhotrix Vector Spaces  

ERIC Educational Resources Information Center

|By rhotrix we understand an object that lies in some way between (n x n)-dimensional matrices and (2n - 1) x (2n - 1)-dimensional matrices. Representation of vectors in rhotrices is different from the representation of vectors in matrices. A number of vector spaces in matrices and their properties are known. On the other hand, little seems to be…

Aminu, Abdulhadi

2010-01-01

301

Nonviral Vector Systems  

Microsoft Academic Search

Gene therapy requires efficient vectors for delivering therapeutic genes. Advances in developments of nonviral vectors have\\u000a been established for improving the efficiency of gene delivery. This chapter describes different nonviral methods as well\\u000a as their applications. Some new directions in developing nonviral vectors are also discussed.

Pui-yan Lee; Leaf Huang

302

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

National Technical Information Service (NTIS)

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 frequ...

B. A. Wielicki F. G. Rose P. Minnis S. Kato S. Sun-Mack W. F. Miller Y. Chen

2009-01-01

303

Asymptotic Code Vector Density in Topographic Vector Quantizers.  

National Technical Information Service (NTIS)

A noise robust vector quantizer model is used to derive expressions for the asymptotic code vector density in various types of topographic vector quantizers. A topographic vector quantizer is not identical to a standard (i.e., Kohonen) topographic mapping...

S. P. Luttrell

1990-01-01

304

Auditory Motion Capturing Ambiguous Visual Motion  

PubMed Central

In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left or rightward auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left or rightward) more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

Alink, Arjen; Euler, Felix; Galeano, Elena; Krugliak, Alexandra; Singer, Wolf; Kohler, Axel

2012-01-01

305

Observing, Describing, and Identifying Clouds  

NSDL National Science Digital Library

In this activity students observe and sketch clouds, describing their forms. They initially generate descriptions of a personal nature and then move toward building a more scientific vocabulary. They then correlate their descriptions with the standard classifications using the ten cloud types identified for GLOBE. Each student develops a personal cloud booklet to be used in conjunction with the GLOBE Cloud Chart. . The intended outcome is that students will be able to identify cloud types using standard cloud classification names.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

306

Vector coding the finite volume procedure for the CYBER 205  

NASA Astrophysics Data System (ADS)

The architecture of supercomputers and fundamental principles of vector programming in FORTRAN are reviewed, and vector coding and execution of the finite volume procedure on the CYBER 205 are described. With the proper structure given to the data base each coordinate direction can be differenced throughout the entire grid in one vector operation. Boundary conditions must be interleaved, which inhibits the concurrency of the overall scheme. No data motion together with inner-loop vectorization is advocated. The computed example of transonic flow separating from the sharp leading edge of a delta wing demonstrates the performance of the procedure. Vectors over 20,000 elements long are obtained, and a rate of over 50 megaflops sustained over the entire computation indicates the high degree of vectorization achieved.

Rizzi, A.

307

Stereoscopic (cyclopean) motion sensing.  

PubMed

This paper reviews literature on the motion processing of dynamic change in binocular disparity, called stereoscopic (cyclopean) motion. Studies investigating the visual processing of stereoscopic motion in the Z-axis, stereoscopic motion in the X/Y plane, and cyclopean motion are discussed. It is concluded that stereoscopic motion is processed by a motion-sensing system composed of special-purpose mechanisms that function like low-level motion sensors. For animals with binocular vision, low-level motion processing may involve, at least in part, stereoscopic processing. PMID:10615499

Patterson, R

1999-10-01

308

Computing and Partitioning Cloud Feedbacks using Cloud Property Histograms  

NASA Astrophysics Data System (ADS)

In this study we propose a novel technique for computing cloud feedbacks using histograms of cloud fraction as joint functions of cloud top pressure and optical depth generated by the International Satellite Cloud Climatology Project (ISCCP) simulator, which was incorporated into the climate models that took part in the Cloud Feedback Model Intercomparison Project. We use a radiative transfer model to compute top of atmosphere (TOA) flux sensitivities to cloud fraction perturbations in each bin of the ISCCP simulator histogram, which we refer to as a cloud radiative kernel. Multiplying the cloud radiative kernel histogram with the histogram of actual cloud top fraction changes per unit of global warming simulated by each model produces an estimate of cloud feedback. Both the spatial structures and globally integrated values of cloud feedbacks computed in this manner agree remarkably well with those computed by adjusting the change in cloud radiative forcing for clear-sky effects as in Soden et al. (2008). The technique allows us to quantitatively partition cloud feedbacks into contributions from changes in cloud amount, height, and optical depth. We show that rising clouds are the dominant contributor to the positive LW cloud feedback, and that the extra-tropical contribution is approximately 70% as large as the tropical contribution. In the ensemble mean, the positive impact of rising clouds is 50% larger than the negative impact of reductions in cloud amount on LW cloud feedback, but the degree to which reductions in cloud fraction offset the effect of rising clouds varies considerably across models. In contrast, reductions in cloud fraction make a large and virtually unopposed positive contribution to SW cloud feedback, though the inter-model spread is greater than for any other individual feedback component. In general, models exhibiting greater reductions in subtropical marine boundary layer cloudiness tend to have larger positive SW cloud feedbacks, in agreement with previous studies. Overall reductions in cloud amount have twice as large an impact on SW fluxes as on LW fluxes such that the net cloud amount feedback is moderately positive, with no models analyzed here having a negative net cloud amount feedback. Finally, we find that although global mean cloud optical depth feedbacks are generally smaller than the other components, they are the dominant process at high latitudes, a perhaps surprising result considering one might expect increases in total cloud amount associated with the poleward shift of the storm track to dominate. This locally large negative optical depth feedback arises due to a combination of increased cloud water content and changes in phase from ice to liquid.

Zelinka, M. D.; Klein, S. A.; Hartmann, D. L.

2011-12-01

309

Long cloud observations on Mars and implications for boundary layer characteristics over slopes  

NASA Astrophysics Data System (ADS)

The times and locations of occurrence are measured, as are the wavelengths and, when possible, the apparent velocity of motion of these clouds. The wavelengths of the patches of ripple clouds that are often found with the long formations are tabulated. The long clouds are observed only in the early morning hours, suggesting that they are associated with drainage winds caused by a cold planetary boundary layer. Simple mathematical models are developed to examine various aspects of such boundary winds; these make it possible to construct a complete and self-consistent explanation of all the observed features of the cloud formations.

Kahn, R.; Gierasch, P.

1982-02-01

310

Image-based motion estimation for cardiac CT via image registration  

NASA Astrophysics Data System (ADS)

Images reconstructed from tomographic projection data are subject to motion artifacts from organs that move during the duration of the scan. The effect can be reduced by taking the motion into account in the reconstruction algorithm if an estimate of the deformation exists. This paper presents the estimation of the three-dimensional cardiac motion by registering reconstructed images from cardiac quiet phases as a first step towards motion-compensated cardiac image reconstruction. The non-rigid deformations of the heart are parametrized on a coarse grid on the image volume and are interpolated with cubic b-splines. The optimization problem of finding b-spline coefficients that best describe the observed deformations is ill-posed due to the large number of parameters and the resulting motion vector field is sensitive to the choice of initial parameters. Particularly challenging is the task to capture the twisting motion of the heart. The motion vector field from a dynamic computer phantom of the human heart is used to initialize the transformation parameters for the optimization process with realistic starting values. The results are evaluated by comparing the registered images and the obtained motion vector field to the case when the registration is performed without using prior knowledge about the expected cardiac motion. We find that the registered images are similar for both approaches, but the motion vector field obtained from motion estimation initialized with the phantom describes the cardiac contraction and twisting motion more accurately.

Cammin, J.; Taguchi, K.

2010-03-01

311

An efficient scheme for motion estimation using multireference frames in H.264\\/AVC  

Microsoft Academic Search

The multiple reference frame motion compensation (MRMC) supported by H.264 makes use of the redundancy which is between multiple frames to enhance the coding efficiency over a scheme using the single reference frame motion compensation (SRMC) in which motion vectors are searched over a single reference frame. And, the technique using multiple reference frames can combat the channel errors efficiently.

Sung-eun Kim; Jong-ki Han; Jae-gon Kim

2006-01-01

312

Design and implementation of motion compensation for MPEG4 AS profile streaming video decoding  

Microsoft Academic Search

This paper presents an efficient motion compensation architecture for MPEG-4 advanced simple profile at level 5 (ASP@L5) streaming video standard. A novel local memory storage scheme for motion vector prediction is proposed in the paper. In this scheme, local memory for storing differential data of motion information in video packet layer is avoided, and total memory access bandwidth is reduced

He Wei-feng; Mao Zhi-gang; Wang Jin-xiang; Wang Dao-fu

2003-01-01

313

A new method for analysis of motion of carotid plaques from RF ultrasound images  

Microsoft Academic Search

Motion of carotid artery plaques during the cardiac cycle may contribute to plaque disruption and embolism. We have developed a computerized method that objectively analyzes such motion from a sequence of ultrasound (US) radiofrequency (RF) images. A displacement vector map is obtained by 2-D correlation of local areas in consecutive images. From this map, motion dynamics can be quantified and

Jon Bang; Torbjørn Dahl; Annemarieke Bruinsma; Jon Harald Kaspersen; Toril A Nagelhus Hernes; Hans Olav Myhre

2003-01-01

314

ISCCP Global Cloud Cover  

NSDL National Science Digital Library

This animated sequence is a one month sample of composited images from cloud cover data collected from a suite of U.S., European, and Japanese geostationary satellites and U.S. polar orbiting meteorological satellites. This data was composited under the auspices of ISCCP, the International Satellite Cloud Climatology Program.

Pape, Dave; Rossow, William; Walker, Alison

1994-03-13

315

Introduction to Cloud Computing  

Microsoft Academic Search

Cloud computing is not a brand new type of computing, but it is emerging in the mainstream as a powerful and important force of change in the way we manage information and consume and provide information services. This is an introduction to the landscape of cloud computing, the characteristics by which it is defined, and its strengths and its weaknesses.

J. Dale Prince

2011-01-01

316

Weather Fundamentals: Clouds. [Videotape].  

ERIC Educational Resources Information Center

|The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) discusses how clouds form, the different types of clouds, and the important role they play in…

1998

317

On Cloud Nine  

ERIC Educational Resources Information Center

|Across the U.S., innovative collaboration practices are happening in the cloud: Sixth-graders participate in literary salons. Fourth-graders mentor kindergarteners. And teachers use virtual Post-it notes to advise students as they create their own television shows. In other words, cloud computing is no longer just used to manage administrative…

McCrea, Bridget; Weil, Marty

2011-01-01

318

Clues About Clouds  

NSDL National Science Digital Library

In this weather activity which requires adult supervision, learners will get a chance to make a cloud right here on Earth! They learn about the different ingredients a cloud needs in order to form, and then duplicate the process that usually takes place thousands of feet above their heads.

Cosi

2009-01-01

319

Toward green cloud computing  

Microsoft Academic Search

Cloud computing is emerging as a critical information communication technology to heavily impact our daily life in the future. We systematically analyze its energy consumption based on types of services and obtain the conditions to facilitate green cloud computing to save overall energy consumption in the related information communication systems. With a tremendously increasing number of mobile devices, green mobile

Feng-Seng Chu; Kwang-Cheng Chen; Chen-Mou Cheng

2011-01-01

320

Cloud Physics: The Basics  

NSDL National Science Digital Library

This website from the Oklahoma Weather Modification Program encourages students to initiate a debate on the controversy surrounding the issue of inducing or enhancing precipitation. The exercise describes the two basic tenets of cloud seeding: the Static Phase Hypothesis and the Dynamic Phase Hypothesis. Also provided are links to a weather and climate glossary and further information about clouds and precipitation.

Klatt, Michael L.

2008-01-14

321

Formation and spread of aircraft-induced holes in clouds.  

PubMed

Hole-punch and canal clouds have been observed for more than 50 years, but the mechanisms of formation, development, duration, and thus the extent of their effect have largely been ignored. The holes have been associated with inadvertent seeding of clouds with ice particles generated by aircraft, produced through spontaneous freezing of cloud droplets in air cooled as it flows around aircraft propeller tips or over jet aircraft wings. Model simulations indicate that the growth of the ice particles can induce vertical motions with a duration of 1 hour or more, a process that expands the holes and canals in clouds. Global effects are minimal, but regionally near major airports, additional precipitation can be induced. PMID:21719676

Heymsfield, Andrew J; Thompson, Gregory; Morrison, Hugh; Bansemer, Aaron; Rasmussen, Roy M; Minnis, Patrick; Wang, Zhien; Zhang, Damao

2011-07-01

322

An optimal quadtree-based motion estimation and motion-compensated interpolation scheme for video compression  

Microsoft Academic Search

In this paper, we propose an optimal quadtree (QT)- based motion estimator for video compression. It is optimal in the sense that for a given bit budget for encoding the displacement vector field (DVF) and the QT segmentation, the scheme finds a DVF and a QT segmentation which minimizes the energy of the resulting displaced frame difference (DFD). We find

Guido M. Schuster; Aggelos K. Katsaggelos

1998-01-01

323

Limited range of motion  

MedlinePLUS

Limited range of motion is a term meaning that a joint or body part cannot move through its normal range of motion. ... Motion may be limited because of a problem within the joint, swelling of tissue around the joint, ...

324

Motion recognition from contact force measurement.  

PubMed

Optical motion capture systems, which are used in broad fields of research, are costly; they need large installation space and calibrations. We find difficulty in applying it in typical homes and care centers. Therefore we propose to use low cost contact force measurement systems to develop rehabilitation and healthcare monitoring tools. Here, we propose a novel algorithm for motion recognition using the feature vector from force data solely obtained during a daily exercise program. We recognized 7 types of movement (Radio Exercises) of two candidates (mean age 22, male). The results show that the recognition rate of each motion has high score (mean: 86.9%). The results also confirm that there is a clustering of each movement in personal exercises data, and a similarity of the clustering even for different candidates thus that motion recognition is possible using contact force data. PMID:24111417

Yabuki, Takumi; Venture, Gentiane

2013-07-01

325

Multiresolution motion estimation and target detection  

NASA Astrophysics Data System (ADS)

Detecting and characterizing motion in a scene can play a critical role in target detection algorithms, since many targets can be camouflaged so completely that, if they are not moving, they are nearly undetectable. However, once they begin moving, they `popout' and are immediately detected. Estimating motion is also important in human vision modeling, because motion is generally detected with peripheral vision, which can cover the field of regard much more quickly than foveal vision. In this paper, we present two hierarchical multiresolution methods for computing the optical flow in a scene. We use statistical properties of the resulting flow fields to compute a motion feature vector, which we relate to the conspicuity of the moving target in a scene via a neural network.

Karlsen, Robert E.; Gorsich, David J.; Gerhart, Grant R.

1998-07-01

326

An Inexpensive Mechanical Model for Projectile Motion  

NASA Astrophysics Data System (ADS)

As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the calculations. What do our students see? Likely, most see no deeper than the operational understanding needed to use the kinematic equations. Described below is a device (shown in Fig. 1) that illustrates the physicist's view of projectile motion. It can be used as a classroom demonstration or as a project for your students, and it costs less than three dollars to make.

Kagan, David

2011-05-01

327

Index Sets and Vectorization  

SciTech Connect

Vectorization is data parallelism (SIMD, SIMT, etc.) - extension of ISA enabling the same instruction to be performed on multiple data items simultaeously. Many/most CPUs support vectorization in some form. Vectorization is difficult to enable, but can yield large efficiency gains. Extra programmer effort is required because: (1) not all algorithms can be vectorized (regular algorithm structure and fine-grain parallelism must be used); (2) most CPUs have data alignment restrictions for load/store operations (obey or risk incorrect code); (3) special directives are often needed to enable vectorization; and (4) vector instructions are architecture-specific. Vectorization is the best way to optimize for power and performance due to reduced clock cycles. When data is organized properly, a vector load instruction (i.e. movaps) can replace 'normal' load instructions (i.e. movsd). Vector operations can potentially have a smaller footprint in the instruction cache when fewer instructions need to be executed. Hybrid index sets insulate users from architecture specific details. We have applied hybrid index sets to achieve optimal vectorization. We can extend this concept to handle other programming models.

Keasler, J A

2012-03-27

328

PhET Teacher Activities: Vectors Simulations Lab  

NSDL National Science Digital Library

This virtual lab was developed by a high school teacher specifically for use with the PhET simulation "Motion in 2D". It provides explicit direction for using the simulation to explore vector quantities, vector addition, and calculating resultants. In the last half of the activity, students demonstrate understanding by performing specific calculations, then using the simulation to check their work. The lesson includes printable student data tables. The associated simulation (which must be running to complete this activity) is available from PhET at: Motion in 2D.

Bires, Chris

2013-02-05

329

Estimates of magnetic cloud expansion at 1 AU  

NASA Astrophysics Data System (ADS)

In this study we analyze 53 magnetic clouds (MCs) of standard profiles observed in WIND magnetic field and plasma data, in order to estimate the speed of MC expansion (VE) at 1 AU, where the expansion is investigated only for the component perpendicular to the MCs' axes. A high percentage, 83%, of the good and acceptable quality cases of MCs (N(good)=64) were actually expanding, where "good quality" as used here refers to those MCs that had relatively well determined axial attitudes. Two different estimation methods are employed. The "scalar" method (where the estimation is denoted VE,S) depends on the average speed of the MC from Sun-to-Earth (), the local MC's radius (RO), the duration of spacecraft passage through the MC (at average local speed ), and the assumption that =. The second method, the "vector determination" (denoted VE,V), depends on the decreasing value of the absolute value of the Z-component (in MC coordinates) of plasma velocity (|VZ|) across the MC, the closest approach distance (YO), and estimated RO; the Z-component is related to spacecraft motion through the MC. Another estimate considered here, VE,V', is similar to VE,V in its formulation but depends on the decreasing |VZ| across part of the MC, that part between the maximum and minimum points of |VZ| which are usually close to (but not the same as) the boundaries points. The scalar means of estimating VE is almost independent of any MC parameter fitting model results, but the vector means slightly depends on quantities that are model dependent (e.g. |CA|?|YO|/RO). The most probable values of VE from all three means, based on the full set of N=53 cases, are shown to be around 30 km/s, but VE has larger average values of =49 km/s, =36 km/s, and =44 km/s, with standard deviations of 27 km/s, 38 km/s, and 38 km/s, respectively. The linear correlation coefficient for VE,S vs. VE,V' is 0.85 but is lower (0.76) for VE,S vs. VE,V, as expected. The individual values of VE from all three means are usually well below the local Alfvén velocities, which are on average (for the cases considered here) equal to 116 km/s around the inbound boundary, 137 km/s at closest approach, and 94 km/s around the outbound boundary. Hence, a shock upstream of a MC is not expected to be due to MC expansion. Estimates reveal that the errors on the "vector" method of estimating VE (typically about ±7 km/s, but can get as large as ±25 km/s) are expected to be markedly smaller than those for the scalar method (which is usually in the range ±(15⇔20) km/s, depending on MC speed). This is true, despite the fact that |CA| (on which the vector method depends) is not always well determined by our MC parameter fitting model (Lepping et al., 1990), but the vector method only weakly depends on knowledge of |CA|.

Lepping, R. P.; Wu, C.-C.; Berdichevsky, D. B.; Ferguson, T.

2008-07-01

330

A new parameterization for predicting the fast response of stratiform cloud to unresolved diabatic radiative heating  

NASA Astrophysics Data System (ADS)

Conventional GCMs are easily capable of representing the convective response of the atmosphere to the slow cooling of clear skies over timescales of days to weeks. On the other hand, representing the interactions of radiation with cloudy skies lie beyond current GCM capabilities because the the associated heating gradients are so sharp, and these drive circulations a traditional GCM framework cannot resolve. Moreover, because clouds are partly the consequence of the very circulations they drive, the problem quickly becomes non-linear and difficult to parameterize. Using a combination of LES simulations and simple theoretical arguments, we have found that a single dimensionless “Spreading Number” S captures the small-scale, fast response of horizontally finite stratiform cloud layers to radiative flux convergence/divergence. The Spreading Number factors in local heating gradients, the atmospheric static stability, and the cloud aspect ratio. For very low values of S, where the cloud is either narrow or optically tenuous, the thermodynamic response of the cloud layer to heating is to slowly loft and spread in laminar motions, maintaining continuity while isentropic surfaces stay approximately flat: thin tropopause cirrus is an example. Very large values of S are associated with clouds that are so wide and/or optically dense that heating gradients destabilize the cloud to the point that it convects: one example is the development of mammatus clouds at cirrus anvil cloud base. We suggest that for the purpose of GCM simulations, values of S can be calculated for parameterized cloud cover that cannot be explicitly resolved, and that this offers a shortcut for calculating cloud dynamic fast response over unresolved timescales. Numerical simulation of mammatus cloud using interactive IR radiative heating within the University of Utah LES. Cloud fields are subsequently passed through a 3D radiative transfer solver SHDOM (one quarter domain looking up at cloud base). The mammatus field developed from an initially homogeneous and still cloud layer with a very high value of the spreading number S.

Garrett, T. J.; Schmidt, C. T.

2010-12-01

331

Cloud Formation: A Cloud in a Bottle  

NSDL National Science Digital Library

This activity is designed to be used as either a teacher demonstration or a laboratory activity as part of a weather unit. It reinforces the concepts of condensation, dew point, humidity, pressure, condensation nuclei, and the process of cloud formation. The site has a list of required materials, detailed instructions, questions for the students, and links to other weather-related sites.

Lombardoni, Melissa

332

Cloud computing basics for librarians.  

PubMed

"Cloud computing" is the name for the recent trend of moving software and computing resources to an online, shared-service model. This article briefly defines cloud computing, discusses different models, explores the advantages and disadvantages, and describes some of the ways cloud computing can be used in libraries. Examples of cloud services are included at the end of the article. PMID:22289098

Hoy, Matthew B

2012-01-01

333

Cloud Study Final Art Project  

NSDL National Science Digital Library

This activity is an art project completed at the end of a study of weather and clouds. Using home-made puffy paint, the students paint clouds on a piece of construction paper and write 2-3 facts about each cloud type on a note card that is glued on construction paper next to the appropriate cloud.

Toops, Kim

334

Implementing Trust in Cloud Infrastructures  

Microsoft Academic Search

Today's cloud computing infrastructures usually require customers who transfer data into the cloud to trust the providers of the cloud infrastructure. Not every customer is willing to grant this trust without justification. It should be possible to detect that at least the configuration of the cloud infrastructure—as provided in the form of a hypervisor and administrative domain software—has not been

Ricardo Neisse; Dominik Holling; Alexander Pretschner

2011-01-01

335

Cloud security: myth or reality?  

Microsoft Academic Search

Can the cloud truly be secured? Can enterprises, universities, small businesses and governments securely utilize the cloud for their critical infrastructure? It will take rethinking our current security policies and what we consider secure. This session will cover what is necessary to utilize the cloud securely today and how the cloud should adapt for the future.

Timothy G. Brown

2011-01-01

336

Particle motion in weak relativistic gravitational fields  

NASA Astrophysics Data System (ADS)

We derive the geodesic equation of motion in the presence of weak gravitational fields produced by relativistic sources such as cosmic strings, decomposed into scalar, vector and tensor parts. To test the result, we perform the first N-body simulations with relativistic weak gravitational external fields. Our test case is a moving straight string, for which we recover the well-known result for the impulse on nonrelativistic particles. We find that the vector (gravito-magnetic) force is an essential contributor. Our results mean that it is now possible to incorporate straightforwardly into N-body simulations all weak relativistic sources, including networks of cosmic defects.

Obradovic, Miki; Kunz, Martin; Hindmarsh, Mark; Iliev, Ilian T.

2012-09-01

337

Optical currents in coherent and partially coherent vector fields  

NASA Astrophysics Data System (ADS)

We present the results of computer simulation of spatial distribution of the Poynting vector and illustrate motion of microparticles in spatially inhomogeneously polarized fields. The influence of phase relations and the degree of mutual coherence of superposing waves in the arrangements of two-wave and four-wave superposition on the characteristics of microparicle's motion has been analyzed. The prognosis of prospects of the study of temporal coherence using the proposed approach is made.

Angelsky, O. V.; Maksimyak, P. P.; Zenkova, C. Yu.; Gorsky, M. P.; Gorodynska, N. V.

2010-09-01

338

Motion parallax is used to control postural sway during walking  

Microsoft Academic Search

Three experiments tested the hypothesis that postural sway during locomotion is visually regulated by motion parallax as well as optical expansion. Oscillating displays of three-dimensional scenes were presented to participants walking on a treadmill, while postural sway was recorded. Displays simulated: (a) a cloud, in which parallax and expansion are congruent, (b) a hallway, (c) the side walls of the

Benoît G. Bardy; William H. Warren Jr; Bruce A. Kay

1996-01-01

339

3D motion estimation of atmospheric layers from image sequences  

Microsoft Academic Search

In this paper, we address the problem of esti- mating three-dimensional motions of a stratified atmospher e from satellite image sequences. The analysis of three-dimensional atmospheric fluid flows associated with incomplete observat ion of atmospheric layers due to the sparsity of cloud systems is very difficult. This makes the estimation of dense atmospheric mo tion field from satellite images sequences

Patrick Heas; Etienne Memin

340

Estimating Cloud Cover - a Simulation  

NSDL National Science Digital Library

The purpose of this activity is to help students better understand percent cloud cover and to take more accurate cloud cover observations. Working in pairs or small groups, students use construction paper to simulate cloud cover. They estimate the percentage of cloud cover represented by torn pieces of paper on a contrasting background and assign a cloud cover classification to the simulations created by their classmates. Intended outcomes are that students will understand the difficulties of visually estimating the percentage of cloud cover and gain experience estimating cloud cover, evaluating the accuracy of estimates, and using fractions and percentages.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

341

VAX vector architecture  

Microsoft Academic Search

The VAX architecture has been extended to include an integrated, register-based vector processor. This extension allows both high-end and low-end implementations and can be supported with only small changes by VAX\\/VMS and VAX\\/ULTRIX operating systems. The extension is effectively exploited by the new vectorizing capabilities of VAX Fortran. Features of the VAX vector architecture and the design decisions which make

Dileep Bhandarkar; Richard Brunner

1990-01-01

342

VAX vector architecture  

Microsoft Academic Search

The VAX Architecture has been extended to include an integrated, register-based vector processor. This extension allows both high-end and low-end implementations and can be supported with only small changes by VAX\\/VMS and VAX\\/ULTRIX operating systems. The extension is effectively exploited by the new vectorizing capabilities of VAX FORTRAN. Features of the VAX Vector Architecture and the design decisions which make

Dileep Bhandarkar; Richard Brunner

1990-01-01

343

Four-dimensional non-rigid cardiac motion estimation  

NASA Astrophysics Data System (ADS)

Electrocardiogram-gated cardiac CT reconstruction methods have been developed to reduce motion artifacts; however, projection data used in reconstruction are limited to those within gating time windows, resulting in large image noise. Motion compensated image reconstruction is capable of fully utilizing all projection data if a motion vector field is known. In this work, we propose a non-rigid four-dimensional image-based motion estimation method which uses a nested conjugated gradient method to minimize a cost function. The proposed method is implemented on GPU using CUDA, and its performance was verified with patient data.

Tang, Qiulin; Cammin, Jochen; Srivastava, Somesh; Taguchi, Katsuyuki

2012-02-01

344

Molecular clouds - Cosmic distilleries  

NASA Astrophysics Data System (ADS)

Recent advances in interstellar molecular research are reviewed, with emphasis on interstellar molecules as a tool for studying the physical conditions of molecular clouds, regions of star formation, isotopic abundances, interstellar chemistry, the interaction of stellar winds and molecular clouds, circumstellar shells around late-type stars, galactic structure, and the distribution of molecular clouds in spiral galaxies as a function of morphological type. Tables are presented which list the distributions of inorganic and organic molecular species detected in the Milky Way and other galaxies, and VLBI data from water maser emissions are discussed.

Churchwell, E.

1983-09-01

345

Clouds and Solar Radiation  

NSDL National Science Digital Library

Most people are aware that clouds impact the amount of solar energy that is received at the ground. This lesson examines qualitative and quantitative aspects of how clouds affect incoming solar radiation. Students will be given a visible satellite image, and asked to describe where clouds are located in the state. Given a map of Mesonet solar radiation measurements, the students will be asked to determine regions of relatively high and low values of solar radiation. This lesson also enables students to practice analyzing different types of data sets and compare patterns between two types of data.

346

Invisible motion contributes to simultaneous motion contrast.  

PubMed

The purpose of the present study was two-fold. First we examined whether visible motion appearance was altered by the spatial interaction between invisible and visible motion. We addressed this issue by means of simultaneous motion contrast, in which a horizontal test grating with a counterphase luminance modulation was seen to have the opposite motion direction to a peripheral inducer grating with unidirectional upward or downward motion. Using a mirror stereoscope, observers viewed the inducer and test gratings with one eye, and continuous flashes of colorful squares forming an annulus shape with the other eye. The continuous flashes rendered the inducer subjectively invisible. The observers' task was to report whether the test grating moved upward or downward. Consequently, simultaneous motion contrast was observed even when the inducer was invisible (Experiment 1). Second, we examined whether the observers could correctly respond to the direction of invisible motion: It was impossible (Experiment 2). PMID:19185516

Kawabe, Takahiro; Yamada, Yuki

2009-01-29

347

Society for Vector Ecology  

NSDL National Science Digital Library

Formed in 1968, the Society for Vector Ecology (SOVE) is dedicated to studying "all aspects of the biology, ecology, and control of arthropod vectors and the interrelationships between the vectors and the disease agents they transmit." Comprised of researchers and operational and extension personnel around the globe, SOVE tracks and studies the biological organisms that transmit diseases. The SOVE Website contains information related to the Society (e.g., mission, history), its publications (journal, newsletter -- both .pdf format), and professional opportunities (conferences, employment). Several dozen links to additional vector ecology resources are provided.

2002-01-01

348

Three-Dimensional Motion Estimation of Atmospheric Layers From Image Sequences  

Microsoft Academic Search

In this paper, we address the problem of estimating 3-D motions of a stratified atmosphere from satellite image sequences. The analysis of 3-D atmospheric fluid flows associated with incomplete observation of atmospheric layers due to the sparsity of cloud systems is very difficult. This makes the estimation of dense atmospheric motion field from satellite image sequences very difficult. The recovery

Patrick Héasheas; Etienne Méminmemin

2008-01-01

349

Patterns in High Cloud Coverage  

NSDL National Science Digital Library

Clouds are a collection of water droplets and small ice crystals that are suspended in an atmosphere. Clouds form when moisture rises, cools, and changes to water or ice. It is important to take into consideration exactly how clouds affect the world around us. Clouds are an important determining factor in climate in any region around the globe. In this lesson, students will plot and analyze data for high cloud coverage from a specified location and determine whether or not a pattern exists.

350

Reconstructing Optical Flow Fields by Motion Inpainting  

NASA Astrophysics Data System (ADS)

An edge-sensitive variational approach for the restoration of optical flow fields is presented. Real world optical flow fields are frequently corrupted by noise, reflection artifacts or missing local information. Still, applications may require dense motion fields. In this paper, we pick up image inpainting methodology to restore motion fields, which have been extracted from image sequences based on a statistical hypothesis test on neighboring flow vectors. A motion field inpainting model is presented, which takes into account additional information from the image sequence to improve the reconstruction result. The underlying functional directly combines motion and image information and allows to control the impact of image edges on the motion field reconstruction. In fact, in case of jumps of the motion field, where the jump set coincides with an edge set of the underlying image intensity, an anisotropic TV-type functional acts as a prior in the inpainting model. We compare the resulting image guided motion inpainting algorithm to diffusion and standard TV inpainting methods.

Berkels, Benjamin; Kondermann, Claudia; Garbe, Christoph; Rumpf, Martin

351

The role of induced entrainment in past stratiform cloud seeding experiments  

NASA Astrophysics Data System (ADS)

In the late 1940s, probably the most effective and visually-obvious cloud seeding demonstrations showed that supercooled stratiform clouds could be cleared by seeding with dry ice, dropped from aircraft flying above a cloud deck. Numerous well-documents photos show areas 1-2 miles wide cleared along a flight track. The accepted mechanism of cloud clearing assumed that dry ice induced ice formation in the supercooled liquid cloud, followed by growth of ice at the expense of water, with the larger ice particles ultimately falling as snow. The mechanism was amplified by dynamic feedbacks induced by latent heat release (warming) as liquid water froze, thus propagating the dynamic and freezing/precipitation cycle laterally away from the flight track. Here we show that probably a more important effect is the entrainment and EVAPORATION of cloud water induced by turbulent mixing in the aircraft wake. Under many conditions, evaporation induced by turbulence can generate mixtures of air that are COLDER than the cloudy air or the air above the cloud, thus initiating unstable DOWNWARD (negatively-buoyant) motions, which will self-propagate laterally away from a turbulent flight track. We present here the range of environmental conditions where entrainment/evaporation would be most likely to occur in terms of the temperature difference between cloudy air and air just above cloud top, and the relative humidity of air above cloud top at different temperatures and altitudes in the atmosphere. It is suggested here that past cloud seeding experiments had little to do with glaciation, and more likely resulted from induced entrainment followed by evaporation and downward motions of negatively buoyant air resulting from cloud-top entrainment instability. Buoyancy and condensed water content of mixtures of cloudy air and cloud-free air immediately above cloud top vs. the mixing proportions. A supercooled cloud containing 0.1 g/kg liquid water at 600 mb, -20 degrees C is mixed with air above cloud top that is 0.1 C warmer and drier (70% Rh). For these conditions, over 75% of mixtures that might be created by aircraft-induced turbulence are negatively buoyant, inducing unstable downward motions initiated by evaporative cooling. Maximum cooling occurs at the mixing fraction that precisely evaporates all the initial water content of the cloud.

Walcek, C. J.

2010-12-01

352

Methanol in dark clouds  

NASA Astrophysics Data System (ADS)

The authors report observations, for the first time, of the 20 - 10A+ and E, 2-1 - 1-1 E, and 10 - 00A+ lines of methanol (CH3OH) in three dark cold clouds, TMC 1, L 134N, and B 335. The CH3OH emission is extended in these clouds and shows a complex velocity structure. Clear indications of non LTE excitation are observed in TMC 1. Estimated column densities are a few×1013cm-2. Although less abundant than formaldehyde (H2CO), methanol is almost an order of magnitude more abundant than acetaldehyde (CH3CHO), in these clouds. Dimethyl ether was searched for in L 134N, to an upper limit of 4×1012cm-2 (3?). Implications for dark cloud excitation and chemistry are discussed.

Friberg, P.; Hjalmarson, A.; Madden, S. C.; Irvine, W. M.

1988-04-01

353

NASA Cloud Albedo Animation  

NSDL National Science Digital Library

Clouds greatly affect the Earth's solar energy balance. This animation shows how they deflect a portion of solar energy influx from reaching our planet's surface and how they insulate to prevent a total loss of thermal radiance out into space.

Nasa

354

Microencapsulated Cloud Seeding Materials.  

National Technical Information Service (NTIS)

A process was developed for encapsulating hygroscopic, cloud-seeding agents, sodium chloride and urea. The encapsulation process involves depositing the coating polymer, ethylcellulose, onto finely divided powders using a phase separation-coacervation tec...

J. L. Anderson

1971-01-01

355

Magellanic cloud objects  

NASA Astrophysics Data System (ADS)

In this review, the considerable contributions of IUE to understanding the composition, stellar evolution, interstellar medium, and extinction of the Clouds are discussed and compared with those for the Galaxy. Future directions for UV work are suggested.

Hutchings, J. B.

1984-12-01

356

Reconfigurable Martian Data Cloud  

NASA Astrophysics Data System (ADS)

The objective is to develop a constellation of small satellites in orbit around Mars that would provide a highly scalable and dynamically allocatable high performance computing resource. Key is use of Field Programmable Gate Arrays for the cloud.

Sheldon, D. J.; Moeller, R. C.; Pingree, P.; Lay, N.; Reeves, G.

2012-06-01

357

Windowed motion compensation  

Microsoft Academic Search

A new motion compensation technique using a window which satisfies the perfect reconstruction condition is proposed. THe conventional motion compensation using rectangular blocks often gives discontinuities between neighboring motion compensation blocks in the predicted image. The proposed method is based on a window operation to the data which overlaps an area of the conventional motion compensation block. Computer simulation is

Hiroshi Watanabe; Sharad Singhal

1991-01-01

358

Long-term Behaviour Of Venus Winds At Cloud Level From Virtis/vex Observations  

NASA Astrophysics Data System (ADS)

The Venus Express (VEX) mission has been in orbit to Venus for more than three years now. The VIRTIS instrument onboard VEX observes Venus in two channels (visible and infrared) obtaining spectra and multi-wavelength images of the planet. Images in the ultraviolet range are used to study the upper cloud at 66 km while images in the infrared (1.74 ?m) map the opacity of the lower cloud deck at 48 km. Here we present an analysis of the overall dynamics of Venus’ atmosphere at both levels using observations that cover a large fraction of the VIRTIS dataset. We will present our latest results concerning the zonal winds, the overall stability in the lower cloud deck motions and the variability in the upper cloud. Meridional winds are also observed in the upper and lower cloud in the UV and IR images obtained with VIRTIS. While the upper clouds present a net meridional motion consistent with the upper branch of a Hadley cell the lower cloud present more irregular, variable and less intense motions in the meridional direction. Acknowledgements This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07. RH acknowledges a "Ramón y Cajal” contract from MEC.

Hueso, Ricardo; Peralta, J.; Sánchez-Lavega, A.; Pérez-Hoyos, S.; Piccioni, G.; Drossart, P.

2009-09-01

359

IC for motion-compensated de-interlacing, noise reduction, and picture-rate conversion  

Microsoft Academic Search

An IC for consumer television applies motion estimation and compensation for high quality video format conversion. The chip achieves perfect motion portrayal for all sources including 24, 25, and 30 Hz film material, and many display formats. The true-motion vectors are estimated with a sub-pixel resolution and are used to optimally de-interlace video broadcast signals, perform a motion compensated picture

Gerard de Haan

1999-01-01

360

Rate-distortion optimization of spatial filters for motion-compensated video coding  

Microsoft Academic Search

We propose a novel motion-compensated prediction scheme for improving the rate-distortion performance of motion compensated video coders. Our scheme uses a codebook of filters so that the prediction block is encoded by specifying jointly an integer motion vector and the index of a filter in the codebook. The two-dimensional spatial filter furnishes simultaneously the functions of motion compensation, pixel interpolation

Vincent Fong; Wai-Yip Chan

2004-01-01

361

Studying Clouds and Climate  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides information on the role of CMMAP in the exploration of clouds and climate.CMMAP stands for the Center for Multi-Scale Modeling of Atmospheric Processes. CMMAP scientists are working on a new way to model the climate that will help us to better understand the roles clouds play today and in the future as our climate changes.

2007-01-02

362

On Cloud Computing Security  

Microsoft Academic Search

\\u000a Could computing is the latest development of the modern computing technology. It is the next stage of the Internet evolution.\\u000a Cloud computing provides the organizations with the infrastructure management, various software services and the datacenter\\u000a maintenance. The organizations can reduce their operational cost and concentrate on their strategic planning by using services\\u000a provided by cloud computing. Generally, the success of

Yun Bai; Sean Policarpio

363

Cloud computing security auditing  

Microsoft Academic Search

In the recent era, cloud computing has evolved as a net centric, service oriented computing model. Consumers purchase computing resources as on-demand basis and get worry free with the underlying technologies used. Cloud computing model is composed of three service models Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS) and four deployment

Irfan Gul; Atiq ur Rehman; M Hasan Islam

2011-01-01

364

Marine cloud brightening  

PubMed Central

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.

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

365

Marine cloud brightening.  

PubMed

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. PMID:22869798

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

366

Magellanic Clouds: Stellar Populations  

NASA Astrophysics Data System (ADS)

The Magellanic Clouds (figure 1) have long been seen as the prototypical young STELLAR POPULATION. The presence of young GLOBULAR CLUSTERS in the Clouds spoke to southern hemisphere observers of the opportunity to study close up processes which have not occurred in the Milky Way for a long time. Young globulars are also seen in other gas-rich, highly disturbed environments, such as merging galaxi...

Mould, J.; Murdin, P.

2000-11-01

367

When motion appears stopped: stereo motion standstill.  

PubMed

Motion standstill is different from the usual perceptual experiences associated with objects in motion. In motion standstill, a pattern that is moving quite rapidly is perceived as being motionless, and yet its details are not blurred but clearly visible. We revisited motion standstill in dynamic random-dot stereograms similar to those first used by Julesz and Payne [Julesz B, Payne R (1968) Vision Res 8:433-444]. Three improvements were made to their paradigm to avoid possible confounds: The temporal frequency of the motion stimuli was manipulated independently from that of individual stereo gratings so that the failure of motion perception is not due to inability to compute stereo. The motion of the stereo gratings was continuous across the visual field so that the perceived pattern in motion standstill was not a simple average of a back-and-forth display wobble over time. Observers discriminated three spatial frequencies to demonstrate pattern recognition. Three objective psychophysical methods, instead of merely self-report, were used to objectively demonstrate motion standstill. Our results confirm that motion standstill occurs in dynamic random-dot stereogram motion displays at 4-6 Hz. Motion standstill occurs when the stimulus spatiotemporal frequency combination exceeds that of the salience-based third-order motion system in a spatiotemporal frequency range in which the shape and depth systems still function. The ability of shape systems to extract a representative image from a series of moving samples is a significant component of a biological system's ability to derive a stable perceptual world from a constantly changing visual environment. PMID:17003116

Tseng, Chia-huei; Gobell, Joetta L; Lu, Zhong-Lin; Sperling, George

2006-09-26

368

When Oort Clouds Collide  

NASA Astrophysics Data System (ADS)

If other stars have Oort clouds similar to that theorized for the Sun (roughly spherical, with a radius of 100,000 AU), could the clouds interact during a close stellar passage and transfer material? How likely is it that the Sun's Oort cloud contains comets stripped from other stars’ clouds? We modeled encounters between the Oort clouds of the Sun and passing stars over four billion years. Our simulations showed that over the Sun's lifetime, it would have many encounters resulting in some mass exchange and a handful of encounters resulting in large mass exchange. At least 5% of the Sun's comet population might be from other stars, and potentially much more. The range of mass gained (or lost) integrated over the ensemble of encounters is quite wide. Even in encounters that did not result in exchange of comets in the clouds, our simulations showed that they can still pump up the eccentricity of the orbits of some of the comets into highly elliptical orbits. A few comets gain eccentricities close enough to one to bring them into the inner Solar System, consistent with the observed orbits of hyperbolic and very long period comets. Acknowledgments: CMG was supported by the NAU REU program (funded by NSF, grant number AST-1004107).

Gosmeyer, Catherine; Levine, S.

2012-01-01

369

Extraction of Motion Vectors from an MPEG Stream  

Microsoft Academic Search

Abstract In 1997, a project was started to capture, compress, store, and index up to 24 hours of digital TV broadcasts The work in this report is to help implement this In the first chapter of this report, the overall project is introduced and also the motivation behind particular focus of work The second chapter deals with the theory behind

Joseph Gilvarry

370

Ignition temperature of magnesium powder clouds: a theoretical model.  

PubMed

Minimum ignition temperature of dust clouds (MIT-DC) is an important consideration when adopting explosion prevention measures. This paper presents a model for determining minimum ignition temperature for a magnesium powder cloud under conditions simulating a Godbert-Greenwald (GG) furnace. The model is based on heterogeneous oxidation of metal particles and Newton's law of motion, while correlating particle size, dust concentration, and dust dispersion pressure with MIT-DC. The model predicted values in close agreement with experimental data and is especially useful in predicting temperature and velocity change as particles pass through the furnace tube. PMID:23022411

Chunmiao, Yuan; Chang, Li; Gang, Li; Peihong, Zhang

2012-09-14

371

Polarimetric vector diffraction tomography  

Microsoft Academic Search

Scalar linearized inverse scattering has recently found a unified treatment within the framework of diffraction tomography in either frequency or angular diversity. The linear inverse scattering theory can be extended to electromagnetic vector fields to include complete polarization information. Its essential feature is the formulation of a vector Porter-Bojarski integral equation to be inverted by dyadic algebra. Algorithms are discussed

Michael Brandfass; K. J. Langenberg; A. Fritsch

1994-01-01

372

Retroviruses as vectors.  

PubMed

Recombinant retroviruses have long been used to deliver heterologous genes to mammalian cells. Convenient packaging cell lines and vector plasmids have been distributed widely and 'home-made' retroviral vectors have now become a useful research tool in many laboratories. Compared to more traditional methods of gene transfer, retroviral vectors are extraordinarily efficient gene delivery vehicles which cause no detectable harm as they enter their target cells. In the nucleus the retroviral necleic acid becomes integrated into chromosomal DNA, ensuring its long-term persistence and stable transmission to all future progeny of the transduced cell. Up to 8 kilobases of foreign gene sequence can be packaged in a retroviral vector and this is more than enough for most gene therapy applications. Retroviral vectors can also be manufactured in large quantities to meet very stringent safety specifications. They have therefore been selected as the vectors of choice in 80% of the clinical gene therapy trials that have been approved to date. So far there have been no reported short- or long-term toxicity problems associated with their use in human gene therapy trials, now dating back to 1989. However, despite this impressive record, there is still great scope (and need) for the development of new, improved retroviral vectors and packaging systems to fuel further advances in the field of human gene therapy. In the following discussion, existing retroviral vectors are reviewed and current areas of technological development are emphasised. PMID:7767638

Vile, R G; Russell, S J

1995-01-01

373

New Support Vector Algorithms  

Microsoft Academic Search

We propose a new class of support vector algorithms for regression and classification. In these algorithms, a parameter ? lets one effectively control the number of support vectors. While this can be useful in its own right, the parameterization has the additional benefit of enabling us to eliminate one of the other free parameters of the algorithm: the accuracy parameter

Bernhard Schölkopf; Alex J. Smola; Robert C. Williamson; Peter L. Bartlett

2000-01-01

374

Insect vector transmission assays.  

PubMed

Phytoplasmas are transmitted in a persistent propagative manner by phloem-feeding vectors belonging to the order Hemiptera, suborder Homoptera. Following acquisition from the infected source plant, there is a latent period before the vector can transmit, so transmission assays consist of three basic steps: acquisition, latency, and inoculation. More than 90 vector species (plant-, leafhoppers, and psyllids) have been discovered so far but many others are still undiscovered, and their role in spreading economically important crop diseases is neglected. Therefore, screening for vectors is an essential step in developing rational control strategies targeted against the actual vectors for phytoplasma-associated diseases. The mere detection of a phytoplasma in an insect does not imply that the insect is a vector; a transmission assay is required to provide conclusive evidence. Transmission experiments can be carried out using insects from phytoplasma-free laboratory colonies or field-collections. Moreover, transmission assays can be performed by feeding vectors on an artificial diet through Parafilm(®), after which phytoplasmas can be detected in the sucrose feeding medium by PCR. Transmission trials involve the use of different techniques according to the biology of the different vector species; planthoppers, leafhoppers, and psyllids. PMID:22987407

Bosco, Domenico; Tedeschi, Rosemarie

2013-01-01

375

Evaluation of GISS SCM Simulated Cloud and Radiative Properties Using Both Surface and Satellite Observations  

NASA Astrophysics Data System (ADS)

To evaluate the GISS SCM simulated cloud fractions, three years of surface and GOES satellite data have been collected at DOE ARM Southern Great Plains (SGP) site during 1999-2001. The GOES derived total and high cloud fractions from both 0.5° and 2.5° grid boxes are in excellent agreement with surface observations, suggesting that the ARM point observations can represent large areal observations. Compared to the ARM radar-lidar observed cloud fractions, the SCM simulated most mid-level clouds, overestimated low clouds, and underestimated total and high clouds with additional missed during the summer season. Further studies have revealed that the model simulated cloud fractions are strongly dependent on the large-scale synoptic pattern and its associated variables such as vertical motion and relative humidity. Because a significant amount of clouds over ARM SGP occur during synoptically quiescent conditions, the model has issues producing enough high cloud cover. This work suggests that alterations need to be made to the stratiform cloud scheme to better represent the sub-grid scale cloud variability in this case. The model simulated radiation budget is also evaluated with two years of collocated ARM surface radiation and CERES and GOES TOA radiation over the SGP site during March 2000-Dec. 2001. For this comparison, the model simulated surface and TOA radiation budgets agree well with surface and satellite observations (˜10 W m-2). Model simulated cloud optical depth, however, is about an order of magnitude higher than CERES/GOES retrievals, which may explain why the radiation budget is reasonable and yet total cloud fraction has a negative bias compared to observations. Further study is warranted to better understand how this impacts cloud radiative forcing.

Kennedy, A. D.; Dong, X.; Xi, B.; Del Genio, A.; Wolf, A.; Minnis, P.; Khaiyer, M.; Doelling, D.; Nordeen, M.; Keyes, D.

2009-05-01

376

New techniques in 3D scalar and vector field visualization  

SciTech Connect

At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

Max, N.; Crawfis, R.; Becker, B.

1993-05-05

377

Intracellular trafficking of nonviral vectors  

Microsoft Academic Search

Nonviral vectors continue to be attractive alternatives to viruses due to their low toxicity and immunogenicity, lack of pathogenicity, and ease of pharmacologic production. However, nonviral vectors also continue to suffer from relatively low levels of gene transfer compared to viruses, thus the drive to improve these vectors continues. Many studies on vector–cell interactions have reported that nonviral vectors bind

L K Medina-Kauwe; J Xie; S Hamm-Alvarez

2005-01-01

378

Vector theories in cosmology  

SciTech Connect

This article provides a general study of the Hamiltonian stability and the hyperbolicity of vector field models involving both a general function of the Faraday tensor and its dual, f(F{sup 2},FF-tilde), as well as a Proca potential for the vector field, V(A{sup 2}). In particular it is demonstrated that theories involving only f(F{sup 2}) do not satisfy the hyperbolicity conditions. It is then shown that in this class of models, the cosmological dynamics always dilutes the vector field. In the case of a nonminimal coupling to gravity, it is established that theories involving Rf(A{sup 2}) or Rf(F{sup 2}) are generically pathologic. To finish, we exhibit a model where the vector field is not diluted during the cosmological evolution, because of a nonminimal vector field-curvature coupling which maintains second-order field equations. The relevance of such models for cosmology is discussed.

Esposito-Farese, Gilles; Pitrou, Cyril; Uzan, Jean-Philippe [GRECO, Institut d'Astrophysique de Paris, UMR 7095-CNRS, Universite Pierre et Marie Curie-Paris 6, 98bis boulevard Arago, F-75014 Paris (France); Institute of Cosmology and Gravitation, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); GRECO, Institut d'Astrophysique de Paris, UMR 7095-CNRS, Universite Pierre et Marie Curie-Paris 6, 98bis boulevard Arago, F-75014 Paris (France) and Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa)

2010-03-15

379

Vector generator scan converter  

DOEpatents

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

Moore, J.M.; Leighton, J.F.

1988-02-05

380

Motion segmentation and cloud tracking on noisy infrared image sequences  

Microsoft Academic Search

Aerial surveillance is an issue of key importance for warship protection. In addition to radar systems, infrared surveillance sensors represent an interesting alternative for remote observation. In this paper, we study such a system and an original approach to the tracking of complex cloudy patterns in noisy infrared image sequences is proposed. We have paid particular attention to robustness with

Ronan Fablet; Philippe Rostaing; Christophe Collet

1998-01-01

381

Novel true-motion estimation algorithm and its application to motion-compensated temporal frame interpolation.  

PubMed

In this paper, a new low-complexity true-motion estimation (TME) algorithm is proposed for video processing applications, such as motion-compensated temporal frame interpolation (MCTFI) or motion-compensated frame rate up-conversion (MCFRUC). Regular motion estimation, which is often used in video coding, aims to find the motion vectors (MVs) to reduce the temporal redundancy, whereas TME aims to track the projected object motion as closely as possible. TME is obtained by imposing implicit and/or explicit smoothness constraints on the block-matching algorithm. To produce better quality-interpolated frames, the dense motion field at interpolation time is obtained for both forward and backward MVs; then, bidirectional motion compensation using forward and backward MVs is applied by mixing both elegantly. Finally, the performance of the proposed algorithm for MCTFI is demonstrated against recently proposed methods and smoothness constraint optical flow employed by a professional video production suite. Experimental results show that the quality of the interpolated frames using the proposed method is better when compared with the MCFRUC techniques. PMID:23060328

Dikbas, Salih; Altunbasak, Yucel

2012-10-04

382

Review of single bunch instabilities driven by an electron cloud  

NASA Astrophysics Data System (ADS)

Electrons generated and accumulated inside the beam-pipe form an “electron cloud” that interacts with a charged particle beam. If the number of electrons is sizable, this beam-cloud interaction can give rise to a two-stream instability, resulting in beam loss or emittance growth. The instability can occur within a single bunch, e.g., passing through the cloud on successive turns in a storage ring, or it can be a multibunch instability, where the motion of successive bunches is coupled via the electron cloud. In this paper, I review the experimental evidence for, simulation approaches to, and analytical treatments of single-bunch two-stream instabilities caused by an electron cloud. Depending on the parameter regime, this type of instability may resemble a coasting-beam instability, classical beam breakup, or transverse mode coupling. It can also cause long-term emittance growth. Despite the apparent similarities, a few fundamental differences distinguish the two-stream instability from a conventional impedance-driven instability, and limit the applicability of established accelerator-physics concepts, like “wakefield.” On the other hand, if, in addition to the electron cloud, space-charge forces, conventional impedance, or beam-beam interaction are also present, these can conspire so as to enhance the growth rate.

Zimmermann, F.

2004-12-01

383

A quantitative method for representing balance strategies of goal-directed human motions.  

PubMed

A movement index termed balance strategy vector (BSV) was developed as a research tool for studying human balance strategies during goal-directed motions. For a given motion (motion capture data), the BSV index quantitatively represents its balance strategy by computing how available body joint DoFs' angular motions affect the formation of the wholebody center-of-mass trajectory. The index facilitates easy and intuitive understanding of balance strategies of various human motions and can assist scientific investigations on human balance strategies. As an example demonstrating the utility of the index, the index was used to explore balance strategies of free-style, sagittal-plane load lifting motions. PMID:18823622

Park, Woojin; Singh, Devender P; Huston, Ronald L; Song, Seongho

2008-09-26

384

CloudSeeding  

NSDL National Science Digital Library

This Topic in Depth begins with a Web site from the Oklahoma Weather Modification Program called Cloud Physics - The Basics (1 ). Students are encouraged to initiate a debate on the controversy surrounding the issue of inducing or enhancing precipitation. Next, the Texas Water Resources Institute Web site, Does Weather Modification Really Work? (3 ) provides a more basic description of cloudseeding. The site offers several categories including The Science of Cloud Seeding, A Brief History of Weather Modification in Texas, Legal and Policy Issues, Current and Future Activities, and more. The Western Kansas Weather Modification Program offers the next site, Aircrew Pictures 2001 (4 ). The page contains pictures of the planes and crew involved in the program as well as pictures from the plane during a mission. Other links on the site contain radar, data, and other information. The next site from ABCNEWS.com is an article entitled Weather as a Weapon? (5 ) The piece explorers what might happen "on some battlefield of the future where the US military could gain a tactical advantage by changing the weather." A discussion on the possibilities of changing the weather, an Air Force research paper and several other links are provided to learn more. The 6th site maintained by the North Dakota State Water Commission is entitled Atmospheric Resources-Photos and Videos (6 ). Here, visitors can find more photographs of cloudseeding equipment and most notably three videos of cloudseeding planes in action. Atmospherics Incorporated, an operations and research company in the field of applied meteorology, provides the next site, The Physical Basis for Seeding Clouds (7 ). The page describes techniques for cloud seeding and has a link to photographs of pyrotechnic seeding devices. The last site provided by North American Weather Consultants, Inc. is titled, Cloud Seeding -Frequently Asked Questions (8 ). The site briefly answers questions such as When did application of modern cloud seeding technology begin?, Is cloud seeding effective?, and Do the commonly used seeding materials pose any direct health or environmental risks?

2002-01-01

385

Double production of vector quarkonia in exclusive Higgs boson decays  

SciTech Connect

Partial widths with respect to the exclusive decays of Standard Model Higgs bosons to pairs of vector quarkonia, H {sup {yields}}J/{psi}J/{psi}, H {sup {yields}}YY, H {sup {yields}}J/{psi}{phi}, and H {sup {yields}}J/{psi}Y, were calculated with allowance for relativistic corrections associated with the internal motion of quarks in qarkonia.

Kartvelishvili, V. G., E-mail: V.Kartvelishvili@lancaster.ac.u [University of Lancaster (United Kingdom); Luchinsky, A. V., E-mail: Alexey.Luchinsky@ihep.ru; Novoselov, A. A., E-mail: Alexey.Novoselov@cern.c [Institute for High Energy Physics (Russian Federation)

2010-06-15

386

GPS constraints on Africa (Nubia) and Arabia plate motions  

Microsoft Academic Search

We use continuously recording GPS (CGPS) and survey-mode GPS (SGPS) observations to determine Euler vectors for relative motion of the African (Nubian), Arabian and Eurasian plates. We present a well-constrained Eurasia-Nubia Euler vector derived from 23 IGS sites in Europe and four CGPS and three SGPS sites on the Nubian Plate (-0.95 +\\/- 4.8°N, -21.8 +\\/- 4.3°E, 0.06 +\\/- 0.005°

S. McClusky; R. Reilinger; S. Mahmoud; D. Ben Sari; A. Tealeb

2003-01-01

387

A GALACTIC ORIGIN FOR HE 0437-5439, THE HYPERVELOCITY STAR NEAR THE LARGE MAGELLANIC CLOUD  

SciTech Connect

We use Hubble Space Telescope imaging to measure the absolute proper motion of the hypervelocity star (HVS) HE 0437-5439, a short-lived B star located in the direction of the Large Magellanic Cloud (LMC). We observe ({mu}{sub {alpha}} {mu}{sub {delta}}) = (+0.53 {+-} 0.25(stat) {+-} 0.33(sys), + 0.09 {+-} 0.21(stat) {+-} 0.48(sys)) mas yr{sup -1}. The velocity vector points directly away from the center of the Milky Way; an origin from the center of the LMC is ruled out at the 3{sigma} level. The flight time of the HVS from the Milky Way exceeds its main-sequence lifetime, thus its stellar nature requires it to be a blue straggler. The large space velocity rules out a Galactic-disk ejection. Combining the HVS's observed trajectory, stellar nature, and required initial velocity, we conclude that HE 0437-5439 was most likely a compact binary ejected by the Milky Way's central black hole.

Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J. [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States); Anderson, Jay; Bond, Howard E.; Livio, Mario [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Gnedin, Oleg Y., E-mail: wbrown@cfa.harvard.ed, E-mail: mgeller@cfa.harvard.ed, E-mail: skenyon@cfa.harvard.ed, E-mail: jayander@stsci.ed, E-mail: bond@stsci.ed, E-mail: mlivio@stsci.ed, E-mail: ognedin@umich.ed [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)

2010-08-10

388

THE INTERNAL STRUCTURE OF CORONAL MASS EJECTIONS: ARE ALL REGULAR MAGNETIC CLOUDS FLUX ROPES?  

SciTech Connect

In this Letter, we investigate the internal structure of a coronal mass ejection (CME) and its dynamics by invoking a realistic initiation mechanism in a quadrupolar magnetic setting. The study comprises a compressible three-dimensional magnetohydrodynamics simulation. We use an idealized model of the solar corona, into which we superimpose a quadrupolar magnetic source region. By applying shearing motions resembling flux emergence at the solar boundary, the initial equilibrium field is energized and it eventually erupts, yielding a fast CME. The simulated CME shows the typical characteristics of a magnetic cloud (MC) as it propagates away from the Sun and interacts with a bimodal solar wind. However, no distinct flux rope structure is present in the associated interplanetary ejection. In our model, a series of reconnection events between the eruptive magnetic field and the ambient field results in the creation of significant writhe in the CME's magnetic field, yielding the observed rotation of the magnetic field vector, characteristic of an MC. We demonstrate that the magnetic field lines of the CME may suffer discontinuous changes in their mapping on the solar surface, with footpoints subject to meandering over the course of the eruption due to magnetic reconnection. We argue that CMEs with internal magnetic structure such as that described here should also be considered while attempting to explain in situ observations of regular MCs at L1 and elsewhere in the heliosphere.

Jacobs, C.; Poedts, S. [Centrum voor Plasma-Astrofysica, Katholieke Universiteit Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium); Roussev, I. I.; Lugaz, N. [Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)], E-mail: Carla.Jacobs@wis.kuleuven.be, E-mail: Stefaan.Poedts@wis.kuleuven.be, E-mail: iroussev@ifa.hawaii.edu, E-mail: nlugaz@ifa.hawaii.edu

2009-04-20

389

Artificial Lower Limb with Myoelectrical Control Based on Support Vector Machine  

Microsoft Academic Search

For the optional control to artificial lower limb and natural gait, an artificial limb model with myoelectrical control was presented, and the recognition method based on support vector machine was discussed. The electromyography signal after pretreating and wavelet packet analyzing was stored in company with the motion of lower limb. Then support vector machine was used to build a model

Peng Yang; Lingling Chen; Xin Guo; Xitai Wang; Lifeng Li

2006-01-01

390

Modular Approach to Physics: Projectile Motion: One Ball  

NSDL National Science Digital Library

This web page contains a simulation-based module on projectile motion with or without air resistance. By controlling the initial velocity, strength of gravity, and drag coefficient of air, the applet promotes understanding of the projectile motion. The Vectors panel allows display of drag force, gravitational force, velocity, and acceleration vectors. The simulation's Help provides detailed lessons with related problems/solutions, learning outcomes, and instructions for use. This item is part of a larger collection of simulation-based physics modules sponsored by the MAP project (Modular Approach to Physics).

2008-05-30

391

Modular Approach to Physics: Work and Energy in Projectile Motion  

NSDL National Science Digital Library

This web page contains a simulation-based module on projectile motion without air resistance. Users can alter the initial trajectory of the ball, the force of gravity, and the mass of the ball. The path of the ball can be traced, showing parabolic motion. Through the vectors menu, the velocity, force of acceleration, and force of gravity vectors can be plotted. The help section provides full instructions for use plus supplementary student activities. This item is part of a larger collection of simulation-based physics modules sponsored by the MAP project (Modular Approach to Physics).

2008-08-15

392

Alignment of the angular momentum vectors of planetary nebulae in the Galactic Bulge  

NASA Astrophysics Data System (ADS)

We use high-resolution H? images of 130 planetary nebulae (PNe) to investigate whether there is a preferred orientation for PNe within the Galactic Bulge. The orientations of the full sample have a uniform distribution. However, at a significance level of 0.01, there is evidence for a non-uniform distribution for those PNe with evident bipolar morphology. If we assume that the bipolar PNe have a unimodal distribution of the polar axis in Galactic coordinates, the mean Galactic position angle is consistent with 90°, i.e. along the Galactic Plane, and the significance level is better than 0.001 (the equivalent of a 3.7? significance level for a Gaussian distribution). The shapes of PNe are related to angular momentum of the original star or stellar system, where the long axis of the nebula measures the angular momentum vector. In old, low-mass stars, the angular momentum is largely in binary orbital motion. Consequently, the alignment of bipolar nebulae that we have found indicates that the orbital planes of the binary systems are oriented perpendicular to the Galactic Plane. We propose that strong magnetic fields aligned along the Galactic Plane acted during the original star formation process to slow the contraction of the star-forming cloud in the direction perpendicular to the Plane. This would have produced a propensity for wider binaries with higher angular momentum with orbital axes parallel to the Galactic Plane. Our findings provide the first indication of a strong, organized magnetic field along the Galactic Plane that impacted on the angular momentum vectors of the resulting stellar population.

Rees, B.; Zijlstra, A. A.

2013-10-01

393

Motion sickness induced by off-vertical axis rotation (OVAR)  

PubMed Central

We tested the hypothesis that motion sickness is produced by an integration of the disparity between eye velocity and the yaw-axis orientation vector of velocity storage. Disparity was defined as the magnitude of the cross product between these two vectors. OVAR, which is known to produce motion sickness, generates horizontal eye velocity with a bias level related to velocity storage, as well as cyclic modulations due to re-orientation of the head re gravity. On average, the orientation vector is close to the spatial vertical. Thus, disparity can be related to the bias and tilt angle. Motion sickness sensitivity was defined as a ratio of maximum motion sickness score to the number of revolutions, allowing disparity and motion sickness sensitivity to be correlated. Nine subjects were rotated around axes tilted 10°–30° from the spatial vertical at 30°/s–120°/s. Motion sickness sensitivity increased monotonically with increases in the disparity due to changes in rotational velocity and tilt angle. Maximal motion sickness sensitivity and bias (6.8°/s) occurred when rotating at 60°/s about an axis tilted 30° Modulations in eye velocity during OVAR were unrelated to motion sickness sensitivity. The data were predicted by a model incorporating an estimate of head velocity from otolith activation, which activated velocity storage, followed by an orientation disparity comparator that activated a motion sickness integrator. These results suggest that the sensory-motor conflict that produces motion sickness involves coding of the spatial vertical by the otolith organs and body tilt receptors and processing of eye velocity through velocity storage.

Sofroniou, Sofronis; Kunin, Mikhail; Raphan, Theodore; Cohen, Bernard

2011-01-01

394

Vectorization on Monte Carlo particle transport: an architectural study using the LANL benchmark “GAMTEB”  

Microsoft Academic Search

Fully vectorized versions of the Los Alamos National Laboratory benchmark code Gamteb, a Monte Carlo photon transport algorithm, were developed for the Cyber 205\\/ETA-10 and Cray X-MP\\/Y-MP architectures. Single-processor performance measurements of the vector and scalar implementations were modeled in a modified Amdahl's Law that accounts for additional data motion in the vector code. The performance and implementation strategy of

Patrick J. Burns; Mark Christon; Roland Schweitzer; O. M. Lubeck; H. J. Wasserman

1989-01-01

395

Quadratic exponential vectors  

SciTech Connect

We give a necessary and sufficient condition for the existence of a quadratic exponential vector with test function in L{sup 2}(R{sup d}) intersection L{sup {infinity}}(R{sup d}). We prove the linear independence and totality, in the quadratic Fock space, of these vectors. Using a technique different from the one used by Accardi et al. [Quantum Probability and Infinite Dimensional Analysis, Vol. 25, p. 262, (2009)], we also extend, to a more general class of test functions, the explicit form of the scalar product between two such vectors.

Accardi, Luigi; Dhahri, Ameur [Volterra Center, University of Roma Tor Vergata, Via Columbia 2, 00133 Roma (Italy)

2009-12-15

396

On the Use of Cloud Forcing to Estimate Cloud Feedback  

Microsoft Academic Search

ABSTRACT Uncertainty in cloud feedback is the leading cause of discrepancy in model,predictions of climate change. The use of observed or model-simulated radiative fluxes to diagnose the effect of clouds on climate sensitivity requires an accurate understanding,of the distinction between,a change in cloud radiative forcing and a cloud feedback. This study compares,simulations from different versions of the GFDL Atmospheric Model

Brian J. Soden; Anthony J. Broccoli; Richard S. Hemler

2004-01-01

397

N2Cloud: Cloud based neural network simulation application  

Microsoft Academic Search

We present N2Cloud, a novel Cloud-based neural network simulation system, which provides and exchanges neural network knowledge and simulation resources to and between arbitrary users on a world-wide basis following the Web 2.0 principle. N2Cloud enables the exchange of knowledge, as neural network objects and paradigms, by a virtual organization environment and delivers ample resources by exploiting the Cloud computing

Altaf Ahmad Huqqani; Xin Li; Peter Paul Beran; Erich Schikuta

2010-01-01

398

Cloud-Top Temperatures for Precipitating Winter Clouds  

Microsoft Academic Search

ABSTRACT To explore the role of cloud microphysics in a large dataset of precipitating clouds, a six- month dataset of satellite -derived cloud-top brightness temperatures,from,GOES longwave infrared (channel 4) satellite data over precipitating surface observing stations is constructed, producing 144 738 observations o f s now, rain, freezing rain, and sleet. The distributions o f cloud-top brightness temperatures were constructed

Jay W. Hanna; David M. Schultz; Antonio R. Irving

2008-01-01

399

CALWATER Overview of the G1 aircraft measurements of cloud-aerosol interactions within winter storms  

NASA Astrophysics Data System (ADS)

A major component of CalWater 2011 was an aircraft campaign with an extensive suite of cloud physics, aerosol, and trace gases instruments. The aircraft flew nearly 70 hours mainly during winter storms over the Sierra Nevada, Central Valley, the Bay area, coastal range and ocean between 1 Feb and 7 Mar 2011. Some of the unique aspects of this campaign that were the basis for the reported initial findings here were: (1) aerosol time-of flight mass spectrometry (ATOFMS) that provided particle by particle chemical composition; (2) Continuous Flow Diffusion Chamber for detecting ice nuclei; (3) Counterflow virtual impactor (CVI) for sampling the residues of evaporated cloud particles or interstitial aerosol; (4) Cloud drop and hydrometeor probes; (5) 3-D winds and thermodynamic parameters. The aircraft was able to document the clouds from the foothills to the crest of the Sierra Nevada at the section between Sacramento and Fresno during several major winter storms and obtain an unprecedented dataset of the cloud dynamics, microphysics and aerosols during fair weather, atmospheric rivers, barrier jet, pre-frontal, frontal and post frontal conditions. Convective clouds are very often triggered at the foothills of the Sierra Nevada by the start of the rising motion. This triggering is often advanced upwind (westward) due to the blocking effect that is typically associated with a barrier jet. When cloud bases are decoupled from the boundary layer they do not ingest the locally generated aerosols, but rather the pristine air that comes from the ocean. With more southerly back trajectories local decoupling can still bring air pollution from the LA basin, for example. Profound differences in aerosol and cloud microstructure were observed between the coupled and decoupled clouds at the Sierra foothills, where, as expected, the decoupled clouds had a more marine nature. In addition to triggering convective clouds at the foothills, the orographic lifting of the air mass creates cap clouds over the upper slopes and the crest. These clouds form in air that is decoupled from the boundary layer and contains aerosols that originated from somewhere over the Pacific and/or in many cases of long range transport from Asia. Conspicuous events of air pollution, mineral dust and other biogenic aerosols were documented to affect profoundly the cloud drop size distributions and ice forming processes in the cap clouds. Often the convective clouds grow into the cap clouds and penetrate them, creating situation of embedded convection, where the convective elements are embedded in very different types of clouds. Being able to directly measure the different aerosol types and origins is critical for disentangling these mixes of clouds that are affected quite differently by aerosols from very different sources. Specific examples will be presented.

Rosenfeld, D.; Prather, K. A.; Comstock, J. M.; DeMott, P. J.; Cazorla, A.; Chemke, R.; Suski, K.; Freud, E.; Leung, L.

2011-12-01

400

On the Kinematics of Undulator Girder Motion  

SciTech Connect

The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

Welch, J

2011-08-18

401

Redundancy, Self-Motion, and Motor Control  

PubMed Central

Outside the laboratory, human movement typically involves redundant effector systems. How the nervous system selects among the task-equivalent solutions may provide insights into how movement is controlled. We propose a process model of movement generation that accounts for the kinematics of goal-directed pointing movements performed with a redundant arm. The key element is a neuronal dynamics that generates a virtual joint trajectory. This dynamics receives input from a neuronal timer that paces end-effector motion along its path. Within this dynamics, virtual joint velocity vectors that move the end effector are dynamically decoupled from velocity vectors that do not. Moreover, the sensed real joint configuration is coupled back into this neuronal dynamics, updating the virtual trajectory so that it yields to task-equivalent deviations from the dynamic movement plan. Experimental data from participants who perform in the same task setting as the model are compared in detail to the model predictions. We discover that joint velocities contain a substantial amount of self-motion that does not move the end effector. This is caused by the low impedance of muscle joint systems and by coupling among muscle joint systems due to multiarticulatory muscles. Back-coupling amplifies the induced control errors. We establish a link between the amount of self-motion and how curved the end-effector path is. We show that models in which an inverse dynamics cancels interaction torques predict too little self-motion and too straight end-effector paths.

Martin, V.; Scholz, J. P.; Schoner, G.

2011-01-01

402

Motion Lab: Position - Time Graphs of Motion  

NSDL National Science Digital Library

The representation depicts a position-time graph showing the motion of an object as it is moved by the user. The user can also move the object to match the motion represented on 8 different types of position-time graphs.

Clement, John M.

403

Robust structure from motion using motion parallax  

Microsoft Academic Search

An efficient and geometrically intuitive algorithm for reliably interpreting the image velocities of moving objects in 3-D is presented. It is well known that under a weak perspective the image motion of points on a plane can be characterized by an affine transformation. It is shown that the relative image motion of a nearby non-coplanar point and its projection on

Roberto Cipolla; Yasukasu Okamoto; Yoshinori Kuno

1993-01-01

404

Auditory Motion Information Drives Visual Motion Perception  

Microsoft Academic Search

BackgroundVision provides the most salient information with regard to the stimulus motion. However, it has recently been demonstrated that static visual stimuli are perceived as moving laterally by alternating left-right sound sources. The underlying mechanism of this phenomenon remains unclear; it has not yet been determined whether auditory motion signals, rather than auditory positional signals, can directly contribute to visual

Souta Hidaka; Wataru Teramoto; Yoichi Sugita; Yuko Manaka; Shuichi Sakamoto; Yôiti Suzuki; Melissa Coleman

2011-01-01

405

On helical vortex motions of moist air  

NASA Astrophysics Data System (ADS)

Two results that are fundamentally different from what takes place in a dry atmosphere have been obtained for adiabatic motions of unsaturated moist air: (1) the steady helical motion of moist air with collinear velocity and vorticity vectors everywhere is dynamically impossible; (2) the spontaneous amplification (generation) of helicity in a moist air due to baroclinicity is dynamically and thermodynamically feasible. In the absence of helicity flux through the boundary of the domain occupied by air flows, the difference between the values of integral helicity H at time instant t delaying at a small time interval from the initial instant t 0 (at which the instantaneous state of air motion is isomorphic either to a steady Beltrami flow or to an irrotational flow) and the initial value of H increases proportionally to ( t - t 0)4. The nonzero value of the proportionality factor is ensured by the difference in values of the Poisson ratio for dry air and water vapor, respectively.

Kurgansky, M. V.

2013-09-01

406

Affine models for motion and shape recovery  

NASA Astrophysics Data System (ADS)

This paper presents an affine model for 3-D motion and shape recovery using two perspective views and their relative 2-D displacement field. The 2-D displacement vectors are estimated as parameters of a 2-D affine model that generalizes standard block matching by allowing affine shape deformations of image blocks and affine intensity transformations. The matching block size is effectively found via morphological size histograms. The parameters of the 3-D affine model are estimated using a least-squares algorithm that requires solving a system of linear equations with rank three. Some stabilization of the recovered motion parameters under noise is achieved through a simple form of MAP estimation. A multi-scale searching in the parameter space is also used to improve accuracy without high computational cost. Experiments on applying these affine models to various real world image sequences demonstrate that they can estimate dense displacement fields and recover motion parameters and object shape with relatively small errors.

Fuh, Chiou-Shann; Maragos, Petros

1992-11-01

407

CLOUD WATER CHEMISTRY AND THE PRODUCTION OF SULFATES IN CLOUDS  

EPA Science Inventory

Measurements are presented of the pH and ionic content of water collected in clouds over Western Washington and the Los Angeles Basin. Evidence for sulfate production in some of the clouds is presented. Not all of the sulfur in the cloud water was in the form of sulfate. However,...

408

Cloud Hooks: Security and Privacy Issues in Cloud Computing  

Microsoft Academic Search

In meteorology, the most destructive extratropical cyclones evolve with the formation of a bent-back front and cloud head separated from the main polar-front, creating a hook that completely encircles a pocket of warm air with colder air. The most damaging winds occur near the tip of the hook. The cloud hook formation provides a useful analogy for cloud computing, in

Wayne A. Jansen

2011-01-01

409

The Remarkable High Pressure of the Local Leo Cold Cloud  

NASA Astrophysics Data System (ADS)

Using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope, we have obtained high-resolution ultraviolet spectra of the C I absorption toward two stars behind the Local Leo Cold Cloud (LLCC). At a distance (?20 pc) that places it well inside the Local Bubble, the LLCC is the nearest example of the coldest known (T ? 20 K) diffuse interstellar clouds. The STIS measurements of the C I fine-structure excitation toward HD 85259 and HD 83023 indicate that the thermal gas pressure of the LLCC is much greater than that of the warm clouds in the Local Bubble. The mean LLCC pressure measured toward these two stars (60,000 cm-3 K) implies an H I density of ?3000 cm-3 and a cloud thickness of ?200 AU at the 20 K cloud temperature. Such a thin, cold, dense structure could arise at the collision interface between converging flows of warm gas. However, the measured LLCC pressure is appreciably higher than that expected in the colliding-cloud interpretation given the velocity and column density constraints on warm clouds in the HD 85259 and HD 83023 sightlines. Additional STIS measurements of the Zn II, Ni II, and Cr II column densities toward HD 85259 indicate that the LLCC has a modest "warm cloud" dust depletion pattern consistent with its low dust-to-gas ratio determined from H I 21 cm and 100 ?m observations. In support of the inferred sheet-like geometry for the LLCC, a multi-epoch comparison of the Na I absorption toward a high-proper-motion background star reveals a 40% column density variation indicative of LLCC Na I structure on a scale of ?50 AU.

Meyer, David M.; Lauroesch, J. T.; Peek, J. E. G.; Heiles, Carl

2012-06-01

410

Parallactic Proper Motion  

NSDL National Science Digital Library

The EJS Parallactic Proper Motion Model illustrates the phenomenon known as parallactic proper motion. Proper motion refers to the progressive (non-oscillatory) apparent motion of a star relative to more distant background stars. If this apparent motion is due to actual motion of the star through space then it is known as "true proper motion." However, this apparent motion can also be due to the motion of Earth (along with the Sun and the rest of the solar system) through space. This motion is known as "parallactic proper motion." In 1783 William Herschel detected parallactic proper motion in several stars and used these motions to determine that the solar system was moving toward a point called the "Solar Apex" in the constellation Hercules. The window displays a celestial sphere (blue), the sun (orange), and one star (white). The initial location of the sun is at the center of the sphere. The sun can be moved in the direction of the Solar Apex by adjusting the Displacement slider. This alters the line of sight from the sun to the star and thus changes the apparent location of the star on the celestial sphere (which is assumed to be infinitely distant). The user can adjust the distance to the star as well as the star's (initial) celestial coordinates. The final celestial coordinates of the star are displayed at the bottom of the window.

Timberlake, Todd

2011-05-18

411

A Governance Model for Cloud Computing  

Microsoft Academic Search

As Cloud Computing begins to move beyond the pure hype stage and into the beginning of mainstream adoption, adopting cloud-based services or moving application services to the cloud brings a number of new risks, including: Cloud availability, Cloud security, Erosion of data integrity, and so on. However, for enterprise which require visibility, trust and control over cloud-based services. To maximize

Zhiyun Guo; Meina Song; Junde Song

2010-01-01

412

The Cloud in the Bottle  

NSDL National Science Digital Library

This activity is designed to demonstrate the effects of pressure and temperature on cloud formation. Students watch a demonstration and then transfer this information to weather maps in order to predict cloud formation and clearing.

413

Physical View of Cloud Seeding  

ERIC Educational Resources Information Center

Reviews experimental data on various aspects of climate control. Includes a discussion of (1) the physics of cloud seeding, (2) the applications of cloud seeding, and (3) the role of statistics in the field of weather modification. Bibliography. (LC)

Tribus, Myron

1970-01-01

414

Physical View of Cloud Seeding  

ERIC Educational Resources Information Center

|Reviews experimental data on various aspects of climate control. Includes a discussion of (1) the physics of cloud seeding, (2) the applications of cloud seeding, and (3) the role of statistics in the field of weather modification. Bibliography. (LC)|

Tribus, Myron

1970-01-01

415

GEWEX Cloud Systems Study (GCSS).  

National Technical Information Service (NTIS)

The Global Energy and Water Cycle Experiment (GEWEX) Cloud Systems Study (GCSS) program seeks to improve the physical understanding of sub-grid scale cloud processes and their representation in parameterization schemes. By improving the description and un...

M. Moncrieff

1993-01-01

416

Numerical study of coupled-bunch instability caused by an electron cloud  

NASA Astrophysics Data System (ADS)

An electron cloud induces a wake force on a charged particle beam which creates correlations between bunches—i.e., a small displacement of a bunch creates a perturbation of the electron cloud, which affects the motions of the following bunches, with the result that a coupled-bunch instability is caused. The coupling mode of the instability is determined by the motion of the electrons in the cloud—that is, it depends on which electrons, moving in a drift space, a weak solenoid field or a strong bending field, are dominant for the instability. We discuss the coupled-bunch instability focusing on the relation between the mode spectrum and the electron motion.

Win, S. S.; Ohmi, K.; Fukuma, H.; Tobiyama, M.; Flanagan, J.; Kurokawa, S.

2005-09-01

417

Understanding Vector Fields.  

ERIC Educational Resources Information Center

|Presented are activities that help students understand the idea of a vector field. Included are definitions, flow lines, tangential and normal components along curves, flux and work, field conservation, and differential equations. (KR)|

Curjel, C. R.

1990-01-01

418

Targeted adenoviral vectors  

NASA Astrophysics Data System (ADS)

The practical implementation of gene therapy in the clinical setting mandates gene delivery vehicles, or vectors, capable of efficient gene delivery selectively to the target disease cells. The utility of adenoviral vectors for gene therapy is restricted by their dependence on the native adenoviral primary cellular receptor for cell entry. Therefore, a number of strategies have been developed to allow CAR-independent infection of specific cell types, including the use of bispecific conjugates and genetic modifications to the adenoviral capsid proteins, in particular the fibre protein. These targeted adenoviral vectors have demonstrated efficient gene transfer in vitro , correlating with a therapeutic benefit in preclinical animal models. Such vectors are predicted to possess enhanced efficacy in human clinical studies, although anatomical barriers to their use must be circumvented.

Douglas, Joanne T.

419

LTR-Vectors.  

National Technical Information Service (NTIS)

The patent application describes the production of vectors composed of portions of retrovirus, particularly of Moloney sarcoma virus DNA including the 'LTR' sequence which can activate genes and additional viral sequences which can 'rescue' these genes in...

G. F. Vande Woude W. L. McClements M. K. Oskarsson D. G. Blair

1981-01-01

420

Vector Mesons at HERA  

SciTech Connect

The rich experimental landscape of exclusive vector meson production at the high energy electron-proton collider HERA is reviewed, with emphasis on the transition from soft to hard diffraction and perturbative QCD interpretations.

Favart, L

2009-03-23

421

Effects of turbulence on the collision rate of cloud droplets  

NASA Astrophysics Data System (ADS)

This dissertation concerns effects of air turbulence on the collision rate of atmospheric cloud droplets. This research was motivated by the speculation that air turbulence could enhance the collision rate thereby help transform cloud droplets to rain droplets in a short time as observed in nature. The air turbulence within clouds is assumed to be homogeneous and isotropic, and its small-scale motion (1 mm to 10 cm scales) is computationally generated by direct numerical integration of the full Navier-Stokes equations. Typical droplet and turbulence parameters of convective warm clouds are used to determine the Stokes numbers (St) and the nondimensional terminal velocities (Sv) which characterize droplet relative inertia and gravitational settling, respectively. A novel and efficient methodology for conducting direct numerical simulations (DNS) of hydrodynamically-interacting droplets in the context of cloud microphysics has been developed. This numerical approach solves the turbulent flow by the pseudo-spectral method with a large-scale forcing, and utilizes an improved superposition method to embed analytically the local, small-scale (10 mum to 1 mm) disturbance flows induced by the droplets. This hybrid representation of background turbulent air motion and the induced disturbance flows is then used to study the combined effects of hydrodynamic interactions and airflow turbulence on the motion and collisions of cloud droplets. Hybrid DNS results show that turbulence can increase the geometric collision kernel relative to the gravitational geometric kernel by as much as 42% due to enhanced radial relative motion and preferential concentration of droplets. The exact level of enhancements depends on the Taylor-microscale Reynolds number, turbulent dissipation rate, and droplet pair size ratio. One important finding is that turbulence has a relatively dominant effect on the collision process between droplets close in size as the gravitational collision mechanism diminishes. A theory was developed to predict the radial relative velocity between droplets at contact. The theory agrees with our DNS results to within 5% for cloud droplets with strong settling. In addition, an empirical model is developed to quantify the radial distribution function. (Abstract shortened by UMI.)

Ayala, Orlando

422

Liquid content of the lower clouds of Venus as determined from Mariner 10 radio occultation  

Microsoft Academic Search

S- and X-band radio occulation data obtained during the Mariner 10 flyby of Venus are analyzed to determine the effects of signal attenuation due to the clouds of Venus. The signal-amplitude data are corrected for errors introduced by spacecraft motion and antenna steering during the occultation, absorption-coefficient profiles are computed, and the liquid content of the Venusian clouds is estimated.

A. J. Kliore; C. Elachi; I. R. Patel; J. B. Cimino

1979-01-01

423

The effects of the lower extremity joint motions on the total body motion in sit-to-stand movement  

Microsoft Academic Search

Objective. The purpose of this study is to investigate the effects of lower extremity joint angular motions on the whole body linear motions in a sit-to-stand movement using a biomechanical model that describes the whole body linear velocity vector as functions of lower extremity joint angular velocities.Design. Two-dimensional video analysis of whole body and joint kinematics.Background. A biomechanical model that

Bing Yu; Nicole Holly-Crichlow; Paul Brichta; Gordon R. Reeves; Cynthia M. Zablotny; Deborah A. Nawoczenski

2000-01-01

424

Poynting-vector filter  

SciTech Connect

A determination is made of frequency components associated with a particular bearing or location resulting from sources emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. The broadband frequency components associated with a specific direction or location of interest are isolated from other components in the power spectrum that are not associated with the direction or location of interest. The collection of pointing vectors can be used to characterize the source.

Carrigan, Charles R. (Tracy, CA)

2011-08-02

425

Optics for vector scanning  

Microsoft Academic Search

Vector scanning of laser beams is critical to the success of stereolithography, laser marking, CAD-output-to-microfilm and many other industrial applications. The design of a vector scan lens system can assume many different configurations. This paper will discuss pre-objective, and post-objective alternatives for two and three axis scanning. Various parameters required for system specification are reviewed and the basic configuration of

Jonathan S. Ehrmann

1991-01-01

426

Relative Velocity and Vectors  

NSDL National Science Digital Library

This activity is designed to enhance student comprehension of air and wind velocity, through the use of real time flight data. Students will read about relative velocity, complete a work sheet on vectors, and then gather and analyze real world data. All of the materials, including links to sites for data collection, are provided in this learning object. After completing the activity, students will be able to define relative velocity, add and subtract vectors, and determine aircraft speed using raw data.

Weaver, David

2009-11-16

427

Ash cloud aviation advisories  

SciTech Connect

During the recent (12--22 June 1991) Mount Pinatubo volcano eruptions, the US Air Force Global Weather Central (AFGWC) requested assistance of the US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) in creating volcanic ash cloud aviation advisories for the region of the Philippine Islands. Through application of its three-dimensional material transport and diffusion models using AFGWC meteorological analysis and forecast wind fields ARAC developed extensive analysis and 12-hourly forecast ash cloud position advisories extending to 48 hours for a period of five days. The advisories consisted of ``relative`` ash cloud concentrations in ten layers (surface-5,000 feet, 5,000--10,000 feet and every 10,000 feet to 90,000 feet). The ash was represented as a log-normal size distribution of 10--200 {mu}m diameter solid particles. Size-dependent ``ashfall`` was simulated over time as the eruption clouds dispersed. Except for an internal experimental attempt to model one of the Mount Redoubt, Alaska, eruptions (12/89), ARAC had no prior experience in modeling volcanic eruption ash hazards. For the cataclysmic eruption of 15--16 June, the complex three-dimensional atmospheric structure of the region produced dramatically divergent ash cloud patterns. The large eruptions (> 7--10 km) produced ash plume clouds with strong westward transport over the South China Sea, Southeast Asia, India and beyond. The low-level eruptions (< 7 km) and quasi-steady-state venting produced a plume which generally dispersed to the north and east throughout the support period. Modeling the sequence of eruptions presented a unique challenge. Although the initial approach proved viable, further refinement is necessary and possible. A distinct need exists to quantify eruptions consistently such that ``relative`` ash concentrations relate to specific aviation hazard categories.

Sullivan, T.J.; Ellis, J.S. [Lawrence Livermore National Lab., CA (United States); Schalk, W.W.; Nasstrom, J.S. [EG and G, Inc., Pleasanton, CA (United States)

1992-06-25

428

Polar Stratospheric Clouds from SOLVE  

NSDL National Science Digital Library

Polar stratospheric clouds form at extremely low temperatures in the upper atmosphere. Should the temperature rise, clouds wont form. In this visualization, sequential temperature readings taken in the research area for SOLVE (Stratospheric Ozone Loss and Validation Experiment) are plotted against a threshold temperature for PSC formation. These are clouds essentially made of nitric acid. Note how the area covered by the clouds increases as winter progresses. The red point on the map indicates the location of Kiruna, Sweden, the SOLVE staging area.

Fekete, George; Newman, Paul

2000-05-30

429

Green Cloud on the Horizon  

NASA Astrophysics Data System (ADS)

This paper proposes a Green Cloud model for mobile Cloud computing. The proposed model leverage on the current trend of IaaS (Infrastructure as a Service), PaaS (Platform as a Service) and SaaS (Software as a Service), and look at new paradigm called "Network as a Service" (NaaS). The Green Cloud model proposes various Telco's revenue generating streams and services with the CaaS (Cloud as a Service) for the near future.

Ali, Mufajjul

430

Optical Angular Motion Sensor.  

National Technical Information Service (NTIS)

The Optical Angular Motion Sensor (OAMS) Program, Phase I, consisted of the design, fabrication, test and analysis of a Triaxial Angular Motion Sensor. A brassboard system was fabricated and assembled. It included a transmitter, a receiver assembly and an...

H. T. Braswell J. W. Fontenot L. L. Hartley B. F. Heinrich W. E. Miller

1975-01-01

431

In the Clouds Photography  

NSDL National Science Digital Library

In the Clouds Photography specializes in photos of weather skyscapes taken by a photographer who is also an atmospheric scientist. Spectacular images of tornadoes, lightning, supercells, and other related severe weather are available, as are weather photos of a less severe nature;strange cloud forms and optical phenomenon such as rainbows, halos, and glories. Weather-related photos are a specialty but this web site also contains galleries that generally fit within the Landscape, Nature, and Travel photo themes with hundreds of photos of mountain scenes, flowers, trees, etc. Use the site's Search function for specific topics or simply peruse the Gallery.

Thompson, Gregory

2000-01-01

432

Vapor cloud explosion analysis  

SciTech Connect

This paper introduces a new method (now commonly referred to as the Baker-Strehlow Method) for estimating pressure and impulse generated by vapor cloud explosions. Strehlow`s blast curves and concepts from the Multi-Energy method for determination of explosion energy are applied in this technique. New correlations for maximum flame speed based on obstacle density, fuel reactivity, and cloud confinement allow selection of the appropriate blast curve. Application of these correlations removes much of the subjectivity present in existing explosion estimates. 11 refs., 3 figs., 1 tab.

Baker, Q.A. [Wilfred Baker Engineering Inc., San Antonio, TX (United States); Tang, Ming Jun [Nanjing Univ. of Science and Technology (China); Scheier, E.A. [Occidental Chemical Corp., Dallas, TX (United States); Silva, G.J. [Occidental International Exploration & Production CO., Bakersfield, CA (United States)

1996-12-31

433

Cloud and Precipitation Radar  

NASA Astrophysics Data System (ADS)

Precipitation or weather radar is an essential tool for research, diagnosis, and nowcasting of precipitation events like fronts or thunderstorms. Only with weather radar is it possible to gain insights into the three-dimensional structure of thunderstorms and to investigate processes like hail formation or tornado genesis. A number of different radar products are available to analyze the structure, dynamics and microphysics of precipitation systems. Cloud radars use short wavelengths to enable detection of small ice particles or cloud droplets. Their applications differ from weather radar as they are mostly orientated vertically, where different retrieval techniques can be applied.

Hagen, Martin; Höller, Hartmut; Schmidt, Kersten

434

Spatial relationship representation based on cloud model  

NASA Astrophysics Data System (ADS)

By introducing the object cloud into topological space, the spatial relationships between fuzzy objects transform to cloud relationships in cloud space. According to cloud theory, all the spatial objects can be represented by three types object cloud: point-cloud, line-cloud and area-cloud. So the 9-intersection model of spatial topological relations proposed by Egenhofer can be extended by using the new definition of object cloud. The relationship between object clouds is flexible relationship. Different from the crisp relationship model, 9IM, the flexible relationship model by object cloud can be simplified to 4-intersection cloud model(4ICM), including to equal, contain, intersect and disjoint. The cloud operation and virtue cloud can be introduced to representing the fuzzy and uncertain topological relations. The method makes spatial data model enable to model the spatial phenomena with fuzziness and uncertainties, and enriches the cloud theory.

Wang, Zuocheng; Xue, Lixia

2009-10-01

435

Vision-based motion planning for an autonomous motorcycle on ill-structured roads  

Microsoft Academic Search

We report our development of a vision-based motion planning system for an autonomous motorcycle designed for desert terrain, where uniform road surface and lane markings are not present. The motion planning is based on a vision vector space (V2-Space), which is an unitary vector set that represents local collision-free directions in the image coordinate system. V2-Space is constructed by extracting

Dezhen Song; Hyun Nam Lee; Jingang Yi; Anthony Levandowski

2007-01-01

436

Guiding Center Motion  

SciTech Connect

The motion of charged particles in slowly varying electromagnetic fields is analyzed. The strength of the magnetic field is such that the gyro-period and the gyro-radius of the particle motion around field lines are the shortest time and length scales of the system. The particle motion is described as the sum of a fast gyro-motion and a slow drift velocity.

Blank, H.J. de [FOM-Institute for Plasma Physics Rijnhuizen (Netherlands)

2004-03-15

437

Motion Toward and Away  

NSDL National Science Digital Library

Learn to differentiate between graphs of forward and backward motion. Predict what graphs look like before using a motion sensor, and then compare your predictions with real data. Respond to questions about several other position-time graphs and also explore position-time graphs that do not start at the origin (0,0). Motion Toward and Away is the second of five SmartGraphs activities designed for a typical physical science unit of study on the motion of objects.

Consortium, The C.

2012-02-07

438

Compensation of Target Motion  

NASA Astrophysics Data System (ADS)

In ion beam therapy (IBT), organ motion requires special procedures. Of general concern is the impact on the dose distribution as a result of motion-related changes in the beam's range. In addition, interplay effects can arise for scanned beam application which cannot be addressed by the so-called margins to increase the treated volume. Dedicated motion mitigation techniques and/or 4D treatment planning are required. This chapter introduces the main concepts for management of respiratory motion in IBT.

Bert, Christoph; Rietzel, Eike

439

Venus winds at cloud level from VIRTIS during the Venus Express mission  

NASA Astrophysics Data System (ADS)

The Venus Express (VEX) mission has been in orbit to Venus for almost four years now. The VIRTIS instrument onboard VEX observes Venus in two channels (visible and infrared) obtaining spectra and multi-wavelength images of the planet. Images in the ultraviolet range are used to study the upper cloud at 66 km while images in the infrared (1.74 ?m) map the opacity of the lower cloud deck at 48 km. Here we present our latest results on the analysis of the global atmospheric dynamics at these cloud levels using a large selection over the full VIRTIS dataset. We will show the atmospheric zonal superrotation at these levels and the mean meridional motions. The zonal winds are very stable in the lower cloud at mid-latitudes to the tropics while it shows different signatures of variability in the upper cloud where solar tide effects are manifest in the data. While the upper clouds present a net meridional motion consistent with the upper branch of a Hadley cell the lower cloud present almost null global meridional motions at all latitudes but with particular features traveling both northwards and southwards in a turbulent manner depending on the cloud morphology on the observations. A particular important atmospheric feature is the South Polar vortex which might be influencing the structure of the zonal winds in the lower cloud at latitudes from the vortex location up to 55°S. Acknowledgements This work has been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464-07.

Hueso, Ricardo; Peralta, Javier; Sánchez-Lavega, Agustín.; Pérez-Hoyos, Santiago; Piccioni, Giuseppe; Drossart, Pierre

2010-05-01

440

Reconfigurable Data Processing for Clouds  

Microsoft Academic Search

Reconfigurable computing in the cloud helps to solve many practical problems relating to scaling out data- centers where computation is limited by energy consumption or latency. However, for reconfigurable computing in the cloud to become practical several research challenges have to be addressed. This paper identifies some of the perquisites for reconfigurable computing systems in the cloud and picks out

Anil Madhavapeddy; Satnam Singh

2011-01-01

441

Usage Management in Cloud Computing  

Microsoft Academic Search

User concerns regarding data handling within the cloud will gain increasing importance as cloud computing becomes more pervasive. Existing service level agreement (SLA) frameworks are not designed for flexibly handling even relatively straightforward usage policies. This paper introduces the notion and importance of usage management in cloud computing. It provides an analysis of features and challenges involved in deploying a

Pramod A. Jamkhedkar; Christopher C. Lamb; Gregory L. Heileman

2011-01-01

442

Orleans: Cloud Computing for Everyone  

Microsoft Academic Search

Cloud computing is a new computing paradigm, combining diverse client devices - PCs, smartphones, sensors, single- function, and embedded - with computation and data storage in the cloud. As with every advance in computing, programming is a fundamental challenge, as the cloud is a concurrent, distributed system running on unreliable hardware and networks. Orleans is a software framework for building

Sergey Bykov; Alan Geller; Gabriel Kliot; James R. Larus; Ravi Pandya; Jorgen Thelin

2011-01-01

443

Security Dynamics of Cloud Computing  

Microsoft Academic Search

This paper explores various dimensions of cloud computing security. It argues that security concerns of cloud computing need to be addressed from the perspective of individual stakeholder. Security focuses of cloud computing are essentially dif- ferent in terms of its characteristics and business model. Conventional way of viewing as well as addressing security such as 'bolting-in' on the top of

Khaled M. Khan

444

The Basics of Cloud Computing  

ERIC Educational Resources Information Center

|Most school business officials have heard the term "cloud computing" bandied about and may have some idea of what the term means. In fact, they likely already leverage a cloud-computing solution somewhere within their district. But what does cloud computing really mean? This brief article puts a bit of definition behind the term and helps one…

Kaestner, Rich

2012-01-01

445

A View from the Clouds  

ERIC Educational Resources Information Center

|Cloud computing is definitely a thing now, but it's not new and it's not even novel. Back when people were first learning about the Internet in the 1990s, every diagram that one saw showing how the Internet worked had a big cloud in the middle. That cloud represented the diverse links, routers, gateways, and protocols that passed traffic around…

Chudnov, Daniel

2010-01-01

446

Precipitation Dynamics of Convective Clouds  

Microsoft Academic Search

The dynamics of precipitation processes represent a typical example for a multi-scale geo-system. The gaps between the scales of the cloud microphysics, resolutions of cloud models and remote sensing methods have to be closed by upscaling or parameterisation techniques. The section gives an overview over the governing processes for the generation of precipitation and the importance of the cloud physics

Günther Heinemann; Christoph Reudenbach

447

The dependence of clouds and their radiative impacts on the large-scale vertical velocity  

NASA Astrophysics Data System (ADS)

Middle-tropospheric vertical velocity(o500) is used to isolate the effect of large-scale dynamics on the observed radiation budget and cloud properties in the Tropics. The ratio of shortwave to longwave cloud forcing (N=-SWCF/LWCF) is approximately 1.2 and independent of the magnitude of w5oo when it is upward over the warmer water. Increasingly negative net cloud forcing (NetCRF) with increasing upward motion is mostly related to an increasing abundance of high-thick clouds. Although a consistent dynamical effect on the annual cycle can be identified, the effect of the PDF of o 500 on long-term variations in the tropical mean radiation budget is generally small compared with observed variations. The East Pacific in 1987 and 1998 showed large reductions of N in association with an increase in the fraction of the area with upward motions, and concomitant increases in high clouds. For the West Pacific in 1998 a large increase/decrease in N/NetCRF was caused not by a change in o500, but rather by a shift of the vertical structure of vertical velocity. The structure of tropical large-scale vertical velocity from ERA-40 is compared with satellite measurements. The first two EOFs of the vertical velocity profile represent the traditional deep circulation (PC1) and a middle level divergence (PC2). Together they explain 90% of total variance and can distinguish the "top-heavy" and "bottom-heavy" vertical motions. Cloud and radiation budget quantities have coherent relationships to PC1 and PC2 at all time scales. The relative importance of PC2 is greater on short temporal scales. "Top-heavy" ascent is associated with deep cloud systems. SWCF depends primarily on PC1, while NetCRF depends more on PC2. High-thin clouds are less sensitive to short-term variations of the vertical velocity. Shallow precipitation measured by TRMM-PR is associated with "bottom-heavy" upward motions. During the evolution of intense precipitating systems, upward motion profiles evolve to a more "top-heavy" shape over time, which is consistent with previous radar and sounding measurements. Associated high-thick clouds develop first and extensive anvil clouds later. These results suggest that the elevated latent heating (stratiform type) is responsible for the development of "top-heavy" upward motion profiles in the Tropics.

Yuan, Jian

448

Relative-Motion Microworld.  

National Technical Information Service (NTIS)

A relative-motion microworld has been designed to aid high-school students in understanding the concepts of relative motion and frames of reference. Relative motion and frames of reference are usually introduced in a high-school physics or mathematics cou...

L. E. Morecroft

1985-01-01

449

Motion signal processing  

Microsoft Academic Search

Techniques from the image and signal processing domain can be successfully applied to designing, modifying, and adapting ani- mated motion. For this purpose, we introduce multiresolution mo- tion filtering, multitarget motion interpolation with dynamic time- warping, waveshaping and motion displacement mapping. The techniques are well-suited for reuse and adaptation of existing mo- tion data such as joint angles, joint coordinates

Armin Bruderlin; Lance Williams

1995-01-01

450

Intelligent compliant motion control  

Microsoft Academic Search

The role of a compliant motion scheme is to control a robot manipulator in contact with its environment. By accommodating with the interaction force, the manipulator can be used to accomplish tasks that involve constrained motions. This paper presents a new work on the compliant motion control for position-controlled manipulator. A new method for achieving efficient interaction between the manipulator

Omar M. Al-jarrah; Yuan F. Zheng

1998-01-01

451

Application of cloud vertical structure from CloudSat to investigate MODIS-derived cloud properties of cirriform, anvil, and deep convective clouds  

NASA Astrophysics Data System (ADS)

CloudSat cloud vertical structure is combined with the CALIPSO Lidar and Collection-5 Level 2 cloud data from Aqua's Moderate Resolution Imaging Spectroradiometer (MODIS) to investigate the mean properties of high/cirriform, anvil, and deep convective (DC) clouds. Cloud properties are sampled over 30°S-30°N for 1 year and compared to existing results of Collection-4 Aqua MODIS high-level cloud observations where cloud types were categorized using the International Satellite Cloud Climatology Project (ISCCP) cloud classification scheme. Results show high/cirriform sampled in this study have high biases in cloud top pressure and temperature due to CloudSat's sensitivity to thin high clouds. Mean cloud properties of DC show reasonable agreement with existing DC results notwithstanding mean cloud optical thickness which is ~23% higher due to the exclusion of thick cirrus and anvil clouds. Anvil cloud properties are a mix between high/cirriform and DC according to ISCCP cloud optical thickness thresholds whereby ~80% are associated with high/cirriform and the other 20% are associated with DC. The variability of cloud effective particle radii was also evaluated using DC with ?5 dBZ echoes at and above 10 km. No evidence of larger cloud effective particle radii are given despite considering higher reaching echoes. Using ISCCP cloud optical thickness thresholds, ~25% of DC would be classified as cirrostratus clouds. These results provide a basis to evaluate the uncertainty of the ISCCP cloud classification scheme and MODIS-derived cloud properties using active satellite observations.

Young, Alisa H.; Bates, John J.; Curry, Judith A.

2013-05-01

452

VectorBase: a data resource for invertebrate vector genomics  

Microsoft Academic Search

VectorBase (http:\\/\\/www.vectorbase.org) is an NIAID-funded Bioinformatic Resource Center focused on invertebrate vectors of human patho- gens. VectorBase annotates and curates vector genomes providing a web accessible integrated resource for the research community. Currently, VectorBase contains genome information for three mosquito species: Aedes aegypti, Anopheles gam- biae and Culex quinquefasciatus, a body louse Pediculus humanus and a tick species Ixodes scapularis.

Daniel Lawson; Peter Arensburger; Peter Atkinson; Nora J. Besansky; Robert V. Bruggner; Ryan Butler; Kathryn S. Campbell; George K. Christophides; Scott Christley; Emmanuel Dialynas; Martin Hammond; Catherine A. Hill; Nathan Konopinski; Neil F. Lobo; Robert M. Maccallum; Gregory R. Madey; Karine Megy; Jason Meyer; Seth Redmond; David W. Severson; Eric O. Stinson; Pantelis Topalis; Ewan Birney; William M. Gelbart; Fotis C. Kafatos; Christos Louis; Frank H. Collins

2009-01-01

453

Cloud properties and associated radiative heating rates in the tropical western Pacific  

SciTech Connect

Radiative heating of the atmosphere affects cloud evolution on the cloud scale and it influences large-scale vertical motion. Obtaining good estimates of radiative heating rate profiles has been difficult due to a lack of cloud profile observations. The Atmospheric Radiation Measurement (ARM) program has been measuring cloud property distributions at sites around the globe including three in the tropical western Pacific (TWP) region. We have analyzed a month of these remote sensing observations at Manus and Nauru to calculate time series of vertical cloud property profiles and radiative heating rates. This data set will be an important tool for describing radiative processes in the tropics and assessing the simulation of these processes in dynamical models.

Mather, Jim H.; McFarlane, Sally A.; Miller, Mark A.; Johnson, Karen L.

2007-03-01

454

Broken and inhomogeneous cloud impact on satellite cloud particle effective radius and cloud-phase retrievals  

Microsoft Academic Search

The impact of sensor resolution on satellite-derived cloud particle effective radius (re) and cloud phase (CPH) for broken and overcast inhomogeneous clouds is investigated for the Cloud Physical Properties (CPP) retrieval algorithm used by the Climate Monitoring Satellite Application Facility. First, synthetic data sets of high-resolution (1 × 1 km2) and low-resolution (3 × 3 km2) radiances are used to

Erwin L. A. Wolters; Hartwig M. Deneke; Bart J. J. M. van den Hurk; Jan Fokke Meirink; Robert A. Roebeling

2010-01-01

455

Ice cloud microphysics inferred from PARASOL satellite observations  

NASA Astrophysics Data System (ADS)

Cirrus clouds are an important element in the radiative balance of the earth, so a good understanding of their radiative and microphysical properties is essential. Remote sensing of cirrus clouds using the state of polarization of the reflected solar radiation in addition to its intensity can provide more information about the microphysics of the ice contained in the cloud. In this study, the reflected solar radiation from cirrus clouds with different mixtures of ice crystals is simulated and compared with satellite observations. Both smooth and roughened particles are considered, including those used for the current operational MODIS collection 5 ice cloud products and a new habit mixture under consideration for the upcoming collection 6 products. The simulations are performed with an adding-doubling model developed by de Haan et al. (1987) which gives the full Stokes vector at the top of the atmosphere (TOA). The simulated results are compared with observations from the POLDER (POLarization and Directionality of the Earth's Reflectances) instrument on the PARASOL (Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) satellite.

Cole, B. H.; Yang, P.; Baum, B. A.; Riedi, J.

2011-12-01

456

Visualizing Nonlinear Vector Field Topology  

Microsoft Academic Search

Abstract| We present our results on the visualization of non-linear vector eld topology. The underlying mathemat- ics is done in Cliord algebra, a system describing geometry by extending the usual vector space by a multiplication of vectors. We started with the observation that all known algorithms for vector eld topology are based on piecewise linear or bilinear approximation and that

Gerik Scheuermann; Heinz Krüger; Martin Menzel; Alyn P. Rockwood

1998-01-01

457

Cloud-vegetation interaction: Use of Normalized Difference Cloud Index for estimation of cloud optical thickness  

Microsoft Academic Search

A new technique to retrieve cloud optical depth for broken clouds above green vegetation using ground-based zenith radiance measurements is developed. By analogy with the Normalized Difference Vegetation Index (NDVI), the Normalized Difference Cloud Index (NDCI) is defined as a ratio between the difference and the sum of two zenith radiances measured for two narrow spectral bands in the visible

A. Marshak; Y. Knyazikhin; A. B. Davis; W. J. Wiscombe; P. Pilewskie

2000-01-01

458

Aerosol cloud generation experiments  

Microsoft Academic Search

This paper provides results from an experimental study performed to evaluate the use of homogeneous and granulated explosive mixture concepts for creating spherical aerosol clouds. In the explosive mixture concept, a small mass of explosive is added to a larger mass of fine inert particulate, and the blend is hand-tamped into a confining cylindrical or spherical structure thereby creating a

A. C. Ratzel; E. J. Constantineau

1990-01-01

459

Cloudman's Mini Cloud Atlas  

NSDL National Science Digital Library

This atlas provides descriptions and photographs of the twelve basic cloud types. Information presented here includes the name and could family of each type, its altitude range, and a brief description of its appearance. Links to additional information are also provided.

Day, John

460

FLIGHTS ACROSS RADIOACTIVE CLOUDS  

Microsoft Academic Search

Danger to personnel and equipment arising from radioactive contamination ; of aircraft after flying across radioactive clouds is discussed. Flights ; performed 20-30 minutes after an atomic bomb explosion are no longer dangerous. ; Radioactive dust penetrating into the aircraft constitutes a serious danger. ; Formation of nitrate in the aircraft decreases the radioactivity. Immediate ; decontamination of the aircraft

Chabowski

1960-01-01

461

Training in the Clouds  

ERIC Educational Resources Information Center

|In this article, the authors share how cloud-based applications, such as Google Calendar, Wikidot, Google Docs, Google Sites, YouTube, and Craigslist, played a big part in the success of their plan of implementing a technology training program for customers and employees. A few years ago the Denver Public Library, where the authors work,…

Pretlow, Cassi; Jayroe, Tina

2010-01-01

462

Cloud computing and collaboration  

Microsoft Academic Search

Purpose – The trends in library systems today is to utilize Web resources and services that the library does not own to provide services and useful innovations for library users. This paper aims to explore the two concepts behind this new trend. Explored will be the concept of cloud computing and Web collaboration, the ideas that are revolutionizing library automation

2009-01-01

463

Seeding the Cloud  

ERIC Educational Resources Information Center

|For any institution looking to shift enterprise resource planning (ERP) systems to the cloud, big savings can be achieved--but only if the school has properly prepped "before" negotiations begin. These three steps can help: (1) Mop up the mess first; (2) Understand the true costs for services; and (3) Calculate the cost of transition.|

Schaffhauser, Dian

2013-01-01

464

Cloud Development Studies.  

National Technical Information Service (NTIS)

The report presents the cloud development data for the Pre-Schooner II high explosive cratering event conducted in a rhyolite medium in southwestern Idaho. Early base surge radius dimensions are given as a function of time in several directions, and are r...

W. C. Day R. F. Rohrer

1966-01-01

465

Computing in the Clouds  

ERIC Educational Resources Information Center

|Web-based applications offer teachers, students, and school districts a convenient way to accomplish a wide range of tasks, from accounting to word processing, for free. Cloud computing has the potential to offer staff and students better services at a lower cost than the technology deployment models they're using now. Saving money and improving…

Johnson, Doug

2010-01-01

466

Living under a Cloud.  

ERIC Educational Resources Information Center

|This article examines the efforts of three high school teachers at Richland High School in Richland (Washington) to change the school logo from a mushroom cloud, the symbol for a nuclear explosion. Opposition to these teachers' efforts has come from school administrators and fellow teachers, students, alumnae, and community residents. (IAH)|

Gursky, Daniel

1991-01-01

467

Living under a Cloud.  

ERIC Educational Resources Information Center

This article examines the efforts of three high school teachers at Richland High School in Richland (Washington) to change the school logo from a mushroom cloud, the symbol for a nuclear explosion. Opposition to these teachers' efforts has come from school administrators and fellow teachers, students, alumnae, and community residents. (IAH)

Gursky, Daniel

1991-01-01

468

Methanol in dark clouds.  

PubMed

We report observations, for the first time, of the 2(0) - 1(0)A+ and E, 2(-1) - 1(-1) E, and 1(0) - 0(0)A+ lines of methanol (CH3OH) in three dark cold clouds, TMC1, L134N, and B335. The CH3OH emission is extended in these clouds and shows a complex velocity structure. Clear indications of non LTE excitation are observed in TMC 1. Estimated column densities are a few 10(13) cm-2. Although less abundant than formaldehyde (H2CO), methanol is almost an order of magnitude more abundant than acetaldehyde (CH3CHO), in these clouds. Dimethyl ether was searched for in L134N, to an upper limit of 4 10(12) cm-2 (3 sigma). Implications for dark cloud excitation and chemistry are discussed. A new, more accurate, rest frequency 96741.39(0.01) MHz is determined for the 2(0) - 1(0) A+ E line of methanol. PMID:11540080

Friberg, P; Madden, S C; Hjalmarson, A; Irvine, W M

1988-01-01

469

Photonic equation of motion with application to the Lamb shift  

SciTech Connect

A photonic equation of motion is proposed which is the scalar product of four-vectors and therefore a Lorentz invariant. A photonic equation of motion, which has not been heretofore established in quantum electrodynamics (QED), would capture the quantum nature of light but yet not have the standard field-operator form, thereby making practical calculations easier to perform. The equation of motion proposed here is applied to the Lamb shift. No divergences exist, and the result agrees with the observed Lamb shift for the 1S{sub 1/2} state of hydrogen within experimental error.

Ritchie, A B

2006-12-21

470

Motion coherence affects human perception and pursuit similarly.  

PubMed

Pursuit and perception both require accurate information about the motion of objects. Recovering the motion of objects by integrating the motion of their components is a difficult visual task. Successful integration produces coherent global object motion, while a failure to integrate leaves the incoherent local motions of the components unlinked. We compared the ability of perception and pursuit to perform motion integration by measuring direction judgments and the concomitant eye-movement responses to line-figure parallelograms moving behind stationary rectangular apertures. The apertures were constructed such that only the line segments corresponding to the parallelogram's sides were visible; thus, recovering global motion required the integration of the local segment motion. We investigated several potential motion-integration rules by using stimuli with different object, vector-average, and line-segment terminator-motion directions. We used an oculometric decision rule to directly compare direction discrimination for pursuit and perception. For visible apertures, the percept was a coherent object, and both the pursuit and perceptual performance were close to the object-motion prediction. For invisible apertures, the percept was incoherently moving segments, and both the pursuit and perceptual performance were close to the terminator-motion prediction. Furthermore, both psychometric and oculometric direction thresholds were much higher for invisible apertures than for visible apertures. We constructed a model in which both perception and pursuit are driven by a shared motion-processing stage, with perception having an additional input from an independent static-processing stage. Model simulations were consistent with our perceptual and oculomotor data. Based on these results, we propose the use of pursuit as an objective and continuous measure of perceptual coherence. Our results support the view that pursuit and perception share a common motion-integration stage, perhaps within areas MT or MST. PMID:10750835

Beutter, B R; Stone, L S